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D. W. Bliss; K. W. Forsythe; S. K. Davis; G. S. Fawcett; D. J. Rabideau; L. L. Horowitz; S. Kraut
Multiple-input multiple-output (MIMO) extensions to radar systems enable a number of advantages compared to traditional approaches. These advantages include improved angle estimation and target detection. In this paper, MIMO ground moving target indication (GMTI) radar is addressed. The concept of coherent MIMO radar is introduced. Comparisons are presented comparing MIMO GMTI and traditional radar performance. Simulations and theoretical bounds for
J. R. Guerci; A. O. Steinhardt
The detection and tracking of ground moving vehicles from airborne radar can be challenging at slow target velocities due to the close space-time (angle-Doppler) proximity of strong competing mainbeam clutter. Moreover, in complex non-stationary clutter environments, conventional space-time adaptive processing (STAP) cannot be relied upon to provide precision ing. In this paper, we re-examine GMTI radar from a multiresolution perspective
The applicability of GMTI MIMO Radar
Michael Zatman
MIMO Radar has been proposed as a technique for improving the Minimum Detectable Velocity (MDV) performance of airborne radar systems. However, the increased pulse repetition frequency associated with waveform multiplexing techniques used in GMTI MIMO Radar increases the amount of range ambiguous clutter the radar must suppress, reducing the amount of clutter-free Doppler space available to detect targets and often
Data mining of GMTI radar databases
Allan Corbeil; Greg Van Patten; Laura Spoldi; B. O'Hern; M. Alford
An innovative data mining algorithm was developed by TSC for application to long-term, wide area ground moving target indication (GMTI) radar databases obtained from both airborne and space-based Intelligence, Reconnaissance and Surveillance (ISR) systems. The algorithm can discover high-value targets of opportunity including convoys in dense civilian background traffic, and was recently demonstrated for a GMTI database collected by an
MIMO Radar Waveform Constraints for GMTI
K. W. Forsythe; D. W. Bliss
Ground moving-target indication (GMTI) provides both an opportunity and challenge for coherent multiple-input multiple-output (MIMO) radar. MIMO techniques can improve a radar's angle estimation and the minimum detectable velocity (MDV) for a target. However, the challenge of clutter mitigation places significant constraints on MIMO radar waveforms. In this paper, the loss of target return because of clutter mitigation (signal-to-noise ratio
Physics-based airborne GMTI radar signal processing
George R. Legters; Joseph R. Guerci
The Knowledge-Aided Sensor Signal Processing and Expert Reasoning (KASSPER) program aims to improve airborne ground moving target indicator (GMTI) radar performance by taking into account all available prior knowledge. One powerful piece of information is that the radar return signal is a superposition of near-ideal plane-waves. A plane-wave signal and clutter model or sampled GMTI radar data can be used
Performance limits for exo-clutter Ground Moving Target Indicator (GMTI) radar.
Doerry, Armin Walter
The performance of a Ground Moving Target Indicator (GMTI) radar system depends on a variety of factors, many which are interdependent in some manner. It is often difficult to 'get your arms around' the problem of ascertaining achievable performance limits, and yet those limits exist and are dictated by physics. This report identifies and explores those limits, and how they depend on hardware system parameters and environmental conditions. Ultimately, this leads to a characterization of parameters that offer optimum performance for the overall GMTI radar system. While the information herein is not new to the literature, its collection into a single report hopes to offer some value in reducing the 'seek time'.
Array configurations and space-time adaptive processing for spaceborne distributed GMTI radar
Yan Zhang; Yunhua Zhang; Xueyan Kang
Ground moving target indication (GMTI) is an important, challenging application of space-based distributed aperture radars. Due to the large baseline of the sparse array, the main beam clutter Doppler spread can be reduced and minimum detectable velocity (MDV) can be improved. The cost is the blind zone problem introduced by spatial ambiguities and the grating lobes due to undersampling in
Performance comparison of fast-scan GMTI\\/STAP architectures
J. B. Gaffney; Gordon Guttrich; B. N. Suresh Babu; Jose A. Torres
This paper presents a study on multibeam radar architectures to provide wide-area fast-scan ground moving target indicator (GMTI) coverage. The minimum dwell time of a GMTI radar system is often determined by the Doppler processor. The revisit rate can be lowered, while still meeting dwell time constraints, by using multibeam techniques to cover more area in each dwell. The two
Preliminary design of a SAR-GMTI processing system for RADARSAT-2 MODEX data
Pierre D. Beaulne; Christoph H. Gierull; C. E. Livinstone; Ishuwa C. Sikaneta; S. Chiu; S. Gong; M. Quinton
The RADARSAT-2 satellite includes an experimental mode, called the moving object detection experiment (MODEX), which is to be used to perform ground moving target indication (GMTI) using a C-band synthetic aperture radar (SAR). During MODEX operation, the SAR antenna is partitioned into two subapertures along the satellite track to sequentially observe the same scene from the same spatial point. By
Spaceborne radar design equations and concepts
S. A. Hovanessian; L. B. Jocic; J. M. Lopez
Spaceborne radar systems (SBR) can be designed for several modes of operation including airborne moving target indication (AMTI), ground moving target indication (GMTI), and synthetic aperture radar (SAR) mapping. Each application imposes a different design constraint, in addition to the nominal power-aperture requirements. AMTI and GMTI modes include consideration of such requirements as area coverage and minimum detectable velocity (MDV).
An airborne synthetic aperture radar (SAR) experiment to support RADARSAT-2 ground moving target indication (GMTI)
C. E. Livingstone; I. Sikaneta; C. H. Gierull; S. Chiu; A. Beaudoin; J. Campbell; J. Beaudoin; S. Gong; T. A. Knight
As part of the preparatory work for the RADARSAT-2 moving object detection experiment (MODEX special operating mode), an airborne experiment was conducted at Canadian Forces Base Petawawa in July 1999 to study synthetic aperture radar (SAR) along-track interferometry (ATI) and SAR displaced phase centre antenna (DPCA) as candidate measurement techniques. The CV 580 SAR system operated by Environment Canada was
GMTI processing using back projection.
Doerry, Armin Walter
Backprojection has long been applied to SAR image formation. It has equal utility in forming the range-velocity maps for Ground Moving Target Indicator (GMTI) radar processing. In particular, it overcomes the problem of targets migrating through range resolution cells.
The experiment results of GMTI in low frequency SAR with dual channels
Chongyi Fan; Xiaotao Huang; Daoxiang An; Hong Zhou
Ground moving target indication (GMTI) in low frequency synthetic aperture radar (SAR) with wide angle and long synthetic aperture time, is more difficult than indication in high frequency system. This paper investigates how to detect and estimate the costant velocities of moving target with low computation load and low false alarm. Based on the 2- dimensional (2D) spectrum of moving
Minimum radar cross section bounds for passive radar responsive tags
P. Bidigare; T. Stevens; B Correll; M. Beauvais
A common problem in ground moving target indication (GMTI) radar is detecting a target with even a large radar cross section (RCS) when its line-of-sight velocity falls below the minimum detectable velocity (MDV) for that radar system. In a cooperative scenario, a target may employ a tagging device, which can shift or spread its Doppler signature to become more detectable.
Dismount modeling and detection from small aperture moving radar platforms
R. K. Hersey; W. L. Melvin; E. Culpepper
Future advanced radar systems must detect targets of diminishing radar cross section (RCS) at low radial velocity, in demanding clutter and interference environments. Presently, a deficiency in radar detection performance exists between the capabilities of synthetic aperture radar (SAR) for fixed target indication and space-time adaptive processing (STAP) for ground moving target indication (GMTI) of targets with low ground track
MTE ground station testbed-a battlefield awareness asset for GMTI exploitation
Robert L. Popp; Nils R. Sandell; Bruce L. Johnson
The focus of this paper is to describe the moving target exploitation (MTE) ground station testbed-a battlefield awareness asset based on the Army's common ground station (CGS) whose primary capability is the exploitation of ground moving target indicator (GMTI) radar data. In this paper, we describe the core GMTI and high range resolution (HRR) exploitation capabilities to be integrated into
UK airborne AESA radar research
Stephen Moore
This reviews current UK airborne active electronically scanned array (AESA) designs, discusses current trends toward higher digitisation and multi-function aperture concepts, and details key future challenges that this technology faces. Specifically, we discuss applications to fast-jets. Key requirements are for higher levels of digitisation to provide the performance required in ECCM, STAP, GMTI, and ESM modes. Building radar systems with
SAR-GMTI processing with Canada's Radarsat 2 satellite
Tim J. Nohara; Peter Weber; A. Premji; C. Livingstone
Space-based radar (SBR) has been proposed for various military and civilian applications, including wide area surveillance and theatre defence. Reliable, slow, ground moving target indication (GMTI) of tanks and jeeps, for example, poses a significant challenge, due to strong clutter returns that occupy most, if not all of the available spectrum. Space-time adaptive processing (STAP) techniques can be used to
The Influence of Target Micromotion on SAR and GMTI
Xiang Li; Bin Deng; Yuliang Qin; Hongqiang Wang; Yanpeng Li
This paper analyzes the influence of typical target micromotions on synthetic aperture radar (SAR) images, azimuth resolution limit, SAR\\/ground moving target indication (GMTI), and MTI. According to the micromotion periods contained in the coherent processing interval, a new range model expansion and a generalized paired echo principle are proposed and applied to underlie the analysis. Several new kinds of image
Multiple-input Multiple-output Ground Moving Target Indicator Radar: Theory and Practice
NASA Astrophysics Data System (ADS)
Bliss, Dan
Multiple-input multiple-output (MIMO) extensions to radar systems enable a number of advantages compared to traditional approaches. These advantages include improved angle estimation and target detection. In this paper, an overview of MIMO radar is provided, and the concept of coherent MIMO radar is defined. The principle focus of the paper is the discussion of MIMO ground moving target indication (GMTI). For GMTI radar modes, the advantages of a coherent MIMO architecture include improved angle estimation and enhanced slow speed target detection. To illustrate this, the concept of coherent MIMO radar is introduced and performance comparisons made between MIMO GMTI and traditional radar GMTI. These comparisons are supported by theoretical bounds, simulations, and experimental results for GMTI angle estimation accuracy and minimum detectable target velocity. For some applications, these results indicate significant potential improvements in clutter-mitigation, signal-to-noise ratio (SNR) loss, and reduction in angle-estimation error for slow-moving targets. The important effects of waveform characteristics is addressed.
Effect of wind turbine micro-Doppler on SAR and GMTI signatures
NASA Astrophysics Data System (ADS)
Bhalla, Rajan; Ling, Hao
In this paper, we present the results of a modeling study to examine the interference effect of microDopplers caused by offshore wind farms on airborne sensors operating in the synthetic aperture radar (SAR) and ground moving target indicator (GMTI) modes. The modeling is carried out by generating CAD instantiations of the dynamic wind turbine and using the high-frequency electromagnetic code Xpatch to perform the scattering calculations. Artifacts in the resulting SAR and GMTI signatures are evaluated for interference with tracking of boats in coastal waters. Results of signal filtering algorithms to reduce the dynamic turbine clutter in both SAR images and GMTI displays are presented.
AESA based dual channel GMTI: mode design & flight trials
Martie M Goulding; Anthony Damini; Andy Stonehouse; Andy Nejman
MDA, SELEX Galileo and DRDC-O recently collaborated on a Canadian DND Defence Industrial Research Program to investigate the potential benefits of an Active Electronically Scanned Array architecture for use in air-to- ground radar modes. The firmware and software for a production PicoSAR AESA radar was modified to simultaneously collect scanning and staring GMTI submodes, each with two channel data. Post-processing
Clutter in the GMTI range-velocity map.
Doerry, Armin Walter
Ground Moving Target Indicator (GMTI) radar maps echo data to range and range-rate, which is a function of a moving target's velocity and its position within the antenna beam footprint. Even stationary clutter will exhibit an apparent motion spectrum and can interfere with moving vehicle detections. Consequently it is very important for a radar to understand how stationary clutter maps into radar measurements of range and velocity. This mapping depends on a wide variety of factors, including details of the radar motion, orientation, and the 3-D topography of the clutter.
GMTI-tracking and information fusion for ground surveillance
NASA Astrophysics Data System (ADS)
Koch, Wolfgang
The aim of ground surveillance with airborne GMTI radar is the near real-time production of a dynamic ground picture. Since the sensors often record merely certain aspects of the situation of interest, information fusion is of particular importance. In addition, even after platform motion compensation by signal processing techniques (STAP), ground moving targets can well be masked by the clutter notch of the sensor. This physical phenomenon directly results from the low-DOPPLER characteristics of the targets and causes interfering fading effects that seriously affect the tracking performance/continuity. In this context a GMTI sensor model provides significant performance improvements being relevant also to sensor data fusion. The Minimum Detectable Velocity (MDV) proves to be an important sensor parameter explicitly entering into GMTI tracking. In combination with road map information or sensor data fusion the refined model can in particular alleviate the recognition of stopping targets. A numerical example quantitatively illustrates the potential gain by exploiting GMTI-modeling, road-maps, and sensor fusion.
Noncooperative rendezvous radar system
NASA Technical Reports Server (NTRS)
A fire control radar system was developed, assembled, and modified. The baseline system and modified angle tracking system are described along with the performance characteristics of the baseline and modified systems. Proposed changes to provide additional techniques for radar evaluation are presented along with flight test data.
NASA Technical Reports Server (NTRS)
Rukao, S.; Tsuda, T.; Sato, T.; Kato, S.
A large clear air radar with the sensitivity of an incoherent scatter radar for observing the whole equatorial atmosphere up to 1000 km altitude is now being designed in Japan. The radar, called the Equatorial Radar, will be built in Pontianak, Kalimantan Island, Indonesia (0.03 N, 109.3 E). The system is a 47 MHz monostatic Doppler radar with an active phased array configuration similar to that of the MU radar in Japan, which has been in successful operation since 1983. It will have a PA product of more than 5 x 10(9) sq. Wm (P = average transmitter power, A = effective antenna aperture) with sensitivity more than 10 times that of the MU radar. This system configuration enables pulse-to-pulse beam steering within 25 deg from the zenith. As is the case of the MU radar, a variety of sophisticated operations will be made feasible under the supervision of the radar controller. A brief description of the system configuration is presented.
Multistatic radar systems signal processing
I. Bradaric; G. T. Capraro; D. D. Weiner; M. C. Wicks
In this paper, a multistatic radar system with multiple receivers and one transmitter is analyzed. We address the rules for selecting the weights for fusing multiple receivers in order to meet pre-specified performance goals. A multistatic radar ambiguity function is used to relate different radar performance measures to system parameters such as radar geometry and radar waveforms. Simulations are used
A joint space-borne radar technology demonstration mission for NASA and the Air Force
P. A. Rosen; M. E. Davis
NASA and the Air Force are currently studying joint technology demonstration concepts for large aperture Space Based Radar (SBR) systems. The mission focuses on elements of NASA's earth science enterprise strategic plan and Air Force long term needs for global airborne and ground moving target indication (GMTI and AMTI) surveillance, and represents an unprecedented multi-agency approach to scientific and technological
Simultaneous SAR and GMTI using ATI/DPCA
NASA Astrophysics Data System (ADS)
Deming, Ross; Best, Matthew; Farrell, Sean
In previous work, we presented GMTI detection and geo-location results from the AFRL Gotcha challenge data set, which was collected using a 3-channel, X-band, circular SAR system. These results were compared against GPS truth for a scripted vehicle target. The algorithm used for this analysis is known as ATI/DPCA, which is a hybrid of along-track interferometry (ATI) and the displaced phase center antenna (DPCA) technique. In the present paper the use of ATI/DPCA is extended in order to detect and geo-locate all observable moving targets in the Gotcha challenge data, including both the scripted movers and targets of opportunity. In addition, a computationally efficient SAR imaging technique is presented, appropriate for short integration times, which is used for computing an image of the scene of interest using the same pulses of data used for the GMTI processing. The GMTI detections are then overlaid on the SAR image to produce a simultaneous SAR/GMTI map.
GMTI STAP in target-rich environments: site-specific analysis
Jameson S. Bergin; Paul M. Techau; William L. Melvin; Joseph R. Guerci
We address the problem of training data corruption in space-time adaptive processing (STAP) for ground moving target indication (GMTI) radar scenarios characterized by high densities of ground targets. A site-specific clutter simulation is used to demonstrate the impact that target signals in the training data have on STAP performance. Measured MCARM data results are presented that reveal similar performance trends
Performance Analysis of a Space-Based GMTI Radar System Using Separated Spacecraft Interferometry
Troy L. Hacker, Raymond J. Sedwick, and David W. Miller May 2000 SERC #2-2000 This report is based on the unaltered thesis of Troy L. Hacker submitted to the Department of Aeronautics and Astronautics in partial Interferometry by TROY L. HACKER Submitted to the Department of Aeronautics and Astronautics on May 24, 2000
A novel multi-channel SAR-GMTI algorithm based on raw data
Anna Liu; Li Chen; Fei Zhao; Gangyao Kuang
This paper presents a novel SAR-GMTI algorithm based on the range-compressed raw data. FrFT is introduced to the classical three-channel DPCA system to realize the moving target detection, parameter estimation and SAR imaging, acquiring an exact GMTI image of accelerative moving targets. As a pretreatment, Keystone transform is firstly applied to process the echoes receiving from each sub-aperture respectively in
Systems and Methods for Radar Data Communication
NASA Technical Reports Server (NTRS)
Bunch, Brian (Inventor); Szeto, Roland (Inventor); Miller, Brad (Inventor)
A radar information processing system is operable to process high bandwidth radar information received from a radar system into low bandwidth radar information that may be communicated to a low bandwidth connection coupled to an electronic flight bag (EFB). An exemplary embodiment receives radar information from a radar system, the radar information communicated from the radar system at a first bandwidth; processes the received radar information into processed radar information, the processed radar information configured for communication over a connection operable at a second bandwidth, the second bandwidth lower than the first bandwidth; and communicates the radar information from a radar system, the radar information communicated from the radar system at a first bandwidth.
The impact of internal clutter motion on a sample matrix inversion space-time adaptive processing algorithm and the GMTI minimum detectable velocity
Richard J. Czernik; John J. SantaPietro
A MATLAB simulation was constructed to better study the effects of internal clutter motion on a notional X band monostatic airborne radar employing a ground moving target indicator (GMTI) algorithm to detect slow velocity targets of low radar cross section. A sample matrix inversion (SMI) fully adapted post-Doppler space-time processor (tapered and untapered) was utilized and the internal clutter motion
An interferometer tracking radar system
NASA Technical Reports Server (NTRS)
Broderick, R. F.
Fine tuning acquisition and tracking interferometer radar system uses a first antenna array of at least three receiving antennas. Array includes a reference antenna, a coarse tuning antenna, and a fine tuning antenna aligned on a receiving axis. Short range rendezvous system provides increased position accuracy.
Obstacle penetrating dynamic radar imaging system
Romero, Carlos E. (Livermore, CA); Zumstein, James E. (Livermore, CA); Chang, John T. (Danville, CA); Leach, Jr.. Richard R. (Castro Valley, CA)
An obstacle penetrating dynamic radar imaging system for the detection, tracking, and imaging of an individual, animal, or object comprising a multiplicity of low power ultra wideband radar units that produce a set of return radar signals from the individual, animal, or object, and a processing system for said set of return radar signals for detection, tracking, and imaging of the individual, animal, or object. The system provides a radar video system for detecting and tracking an individual, animal, or object by producing a set of return radar signals from the individual, animal, or object with a multiplicity of low power ultra wideband radar units, and processing said set of return radar signals for detecting and tracking of the individual, animal, or object.
Installed performance analysis of radar antenna systems
Jacob J. Kim; Oren B. Kesler
If modern airborne radar systems are to function properly, the radar antenna radiation patterns must meet certain specifications. Previously, most radar antennas were designed and tested in a clean antenna environment, i.e., there are no near field scattering from host structures, or radome effects. However, these higher order effects are a matter of increasing concern with added performance demands in
Performance analysis of radar antenna systems
J. J. Kim; O. B. Kesler
If modern airborne radar systems are to function properly, the radar antenna radiation patterns must meet certain specifications. Until recently, most radar antennas were designed and tested in a clean antenna environment, i.e., there is no near field scattering from host structures or radome effects. However, these higher order effects are the matter of increasing concern with added performance demands
Goldstone Solar System Radar (GSSR)
NASA Technical Reports Server (NTRS)
Renzetti, N. A.
The primary objective of the Goldstone Solar System Radar is the investigation of solar system bodies by means of Earth-based radar. Targets of primary interest include the Galilean moons, Saturn's rings and moons, and Earth-approaching asteroids and comets. Planets are also of interest, particularly Mercury and the planets to which NASA has not yet planned spacecraft visits. Based on a history of solid achievement, including the definition of the Astronomical Unit, imaging and topography of Mars, Venus, and Mercury, and contributions to the general theory of relativity, the program will continue to support flight project requirements and its primary objectives. The individual target objectives are presented, and information on the following topics are presented in tabular form: Deep Space Network support, compatibility tests, telemetry, command, and tracking support responsibility.
Enhanced Weather Radar (EWxR) System
NASA Technical Reports Server (NTRS)
Kronfeld, Kevin M. (Technical Monitor)
An airborne weather radar system, the Enhanced Weather Radar (EWxR), with enhanced on-board weather radar data processing was developed and tested. The system features additional weather data that is uplinked from ground-based sources, specialized data processing, and limited automatic radar control to search for hazardous weather. National Weather Service (NWS) ground-based Next Generation Radar (NEXRAD) information is used by the EWxR system to augment the on-board weather radar information. The system will simultaneously display NEXRAD and on-board weather radar information in a split-view format. The on-board weather radar includes an automated or hands-free storm-finding feature that optimizes the radar returns by automatically adjusting the tilt and range settings for the current altitude above the terrain and searches for storm cells near the atmospheric 0-degree isotherm. A rule-based decision aid was developed to automatically characterize cells as hazardous, possibly-hazardous, or non-hazardous based upon attributes of that cell. Cell attributes are determined based on data from the on-board radar and from ground-based radars. A flight path impact prediction algorithm was developed to help pilots to avoid hazardous weather along their flight plan and their mission. During development the system was tested on the NASA B757 aircraft and final tests were conducted on the Rockwell Collins Sabreliner.
Road network estimation through GMTI track fusion
NASA Astrophysics Data System (ADS)
Scalzo, Maria; Jones, Eric; Bubalo, Adnan; Alford, Mark; Wood, Gregory
Road networks and associated traffic flow information are topics that have an innumerable number of applications, ranging from highway planning to military intelligence. Despite the importance of these networks, archival databases that often have update rates on the order of years or even decades have historically been the main source for obtaining and analyzing road network information. This somewhat static view of a potentially changing infrastructure can cause the information to therefore be incomplete and incorrect. Furthermore, these road databases are not only static, but rarely provide information beyond a simple two-dimensional view of a road, where divided high-ways are represented in the same manner as a rural dirt road. It is for these reasons that the use of Ground Moving Target Indicator (GMTI) data and tracks to create road networks is explored. This data lends itself to being able to not only provide a single static snapshot of a network that is considered the network for years, but to provide a consistently accurate and updated changing picture of the environment. The approach employed for creating a road network from GMTI tracks includes a technique known as Continuous Dynamic Time Warping (CDTW), as well as a general fusion routine.
Radar volcano monitoring system in Iceland
NASA Astrophysics Data System (ADS)
Arason, ��r�ur; Yeo, Richard F.; Sigur�sson, Geirfinnur S.; P�lmason, Bolli; von L�wis, Sibylle; N�na Petersen, Gu�r�n; Bjornsson, Halld�r
Weather radars are valuable instruments in monitoring explosive volcanic eruptions. Temporal variations in the eruption strength can be monitored as well as variations in plume and ash dispersal. Strength of the reflected radar signal of a volcanic plume is related to water content and droplet sizes as well as type, shape, amount and the grain size distribution of ash. The Icelandic Meteorological Office (IMO) owns and operates three radars and one more is planned for this radar volcano monitoring system. A fixed position 250 kW C-band weather radar was installed in 1991 in SW-Iceland close to Keflav�k International Airport, and upgraded to a doppler radar in 2010. In cooperation with the International Civil Aviation Organization (ICAO), IMO has recently invested in two mobile X-band radars and one fixed position C-band radar. The fixed position 250 kW doppler C-band weather radar was installed in April 2012 at Flj�tsdalshei�i, E-Iceland, and in June 2012 IMO received a mobile 65 kW dual-polarization doppler X-band radar. Early in 2013 IMO will acquire another mobile radar of the same type. Explosive volcanic eruptions in Iceland during the past 22 years were monitored by the Keflav�k radar: Hekla 1991, Gj�lp 1996, Gr�msv�tn 1998, Hekla 2000, Gr�msv�tn 2004, Eyjafjallaj�kull 2010 and Gr�msv�tn 2011. Additionally, the Gr�msv�tn 2011 eruption was mointored by a mobile X-band radar on loan from the Italian Civil Protection Authorities. Detailed technical information is presented on the four radars with examples of the information acquired during previous eruptions. This expanded network of radars is expected to give valuable information on future volcanic eruptions in Iceland.
James R. Zimbelman; Kenneth S. Edgett
Over 1,000,000 km2 of the equatorial surface of Mars west of the Arsia Mons volcano displays no 3.5-cm radar echo to the very low level of the radar system noise for the Very Large Array; the area displaying this unique property has been terms \\
NASA Technical Reports Server (NTRS)
Brey, H.; Geise, P. E., Jr. (inventors)
An FM/CW radar system is presented with improved noise discrimination in which the received signal is multiplied by a sample of the transmitted signal, and the product signal is employed to deflect a laser beam as a function of frequency. The position of the beam is thus indicative of a discrete frequency, and it is detected by the frequency encoded positions of an array of photodiodes. The outputs of the photodiodes are scanned, then threshold detected, and used to obtain the range and velocity of a target.
THE DEVELOPMENT AND ANALYSIS OF SCANNED PATTERN INTERFEROMETRIC RADAR Karen Marais and Raymond J of Scanned Pattern Interferometric Radar by Karen Marais Submitted to the Department of Aeronautics at the Massachusetts Institute of Technology ABSTRACT A method of performing space based GMTI using radar
Multiple-input multiple-output (MIMO) radar: performance issues
K. W. Forsythe; D. W. Bliss; G. S. Fawcett
The application of multiple-input multiple-output (MIMO) techniques to multistage radar offers a number of advantages, including improved resolution and sensitivity. Depending upon the radar's mode of operation, the array design and the environment, these advantages may or may not be significant. In this paper, a simple analytic model for ground moving target indicator (GMTI) radar detection is presented and its
Laser radar in a system perspective
Vasyl Molebny; Gary Kamerman; Ove Steinvall
As a result of recent achievements in the field of laser radars, new options are available for their operation as system components. In addition to complementing and cross-checking one another, system components can generate new synergetic values. In this article, we address various roles and functions that laser radar may perform in a complete system context. Special attention is paid
Characterisation of a Multistatic Radar System
S. Doughty; K. Woodbridge; C. Baker
In this paper we report on the initial characterisation and calibration of a multistatic radar system, which has been designed using 'commercial off the shelf components'. This initial test strategy will provide a useful gauge of how effectively the system can detect certain simple targets and thus pave the way for further work looking at developing multistatic radar systems
Recent Goldstone Solar System Radar Observations
A. F. Haldemann; L. Benner; B. J. Butler; L. Harcke; R. F. Jurgens; K. W. Larsen; J. Margot; S. J. Ostro; M. A. Slade
Planetary radar exploration started on the ground with the detection of the Moon in 1946. In recent years, the Goldstone Solar System Radar (GSSR) has for example made contributions to (i) understanding of the hazards and trafficability at various proposed Mars robotic landing sites, (ii) under-standing of polar water ice for the terrestrial planets and the surfaces of the icy
Radar target recognition system using 3D mathematical model
Yosuke Nakano; Yoshihisa Hara; Jun Saito; Yoshio Inasawa
A target recognition system is described using 3-D mathematical models which simulate radar images. The simulated radar images are created from radar cross section (RCS) responses of the 3-D models and compared with measured target radar images. The 3-D models consist of several thousands facets, and one facet size is less than the radar resolution. An RCS response of each
ISAT - innovative space-based-radar antenna technology
Joseph Guerci; E. Jaska
ISAT is the innovative space-based-radar antenna technology program of the Defense Advanced Research Projects Agency (DARPA). The goal of the ISAT program is to develop antenna technology to enable tactical grade space-based GMTI (ground moving target indicator) radar - particularly from higher (-10,000 km) orbits which facilitate constellations with fewer satellites.
Moving target detection based on long coherent processing interval for vehicle-borne low frequency SAR system
Zhou Zhimin; Zhou Hong; Huang Xiaotao; Lei Pengzheng; Chang Yulin; Jin Tong
To verify the ground moving target indication (GMTI) ability of low-frequency multi-channel synthetic aperture radar (SAR), a vehicle-borne experimental system has been set up by National University of Defense Technology. Considering the low frequency property of the system, a signal processing procedure is proposed involved in long coherent processing interval (CPI) methods. Some crucial issues in the pre-process for moving
Radar Studies in the Solar System
NASA Technical Reports Server (NTRS)
Shapiro, Irwin I.
We aid in a study of the solar system by means of ground-based radar. We have concentrated on (1) developing the ephemerides needed to acquire radar data at Arecibo Observatory and (2) analyzing the resultant data to: test fundamental laws of gravitation; determine the size, shape, topography, and spin vectors of the targets; and study the surface properties of these objects, through their scattering law and polarization characteristics.
Nested Radar Systems for Remote Coastal Observations
P. S. Bell; J. J. Williams; S. Clark; B. D. Morris; A. Vila-Concejo
BELL, P. S., WILLIAMS, J.J., CLARK, S., MORRIS, B.D. & VILA-CONCEJO A., 2003. Nested Radar Systems for Remote Coastal Observations. Journal of Coastal Research, SI 39 (Proccendigs of the 8th International Coastal Symposium), 438 - 489. Itaja�, SC - Brazil, ISSN 0749-0208 Advances in radar technology now allow the observation of sea surface features at multiple scales, from kilometers, down
Wideband OFDM system for radar and communications
Dmitriy Garmatyuk; Jonathan Schuerger; Kyle Kauffman; Scott Spalding
This paper describes the design and architectural composition of a radar system built on OFDM platform. The radar signal is generated digitally by forming an arbitrary-length vector of OFDM sub-carrier amplitudes and translating it in analog format via 1000 Ms\\/s D\\/A conversion. The resultant baseband signal has a bandwidth of 500 MHz, and variable number and composition of sub-carriers, which
The Colarado Multistatic FMCW Radar System
P. J. F. Swart; J. Schier; A. J. C. van Gemund; W. F. van der Zwan; J. P. Karelse; G. L. Reijns; P. van Genderen; L. P. Ligthart; H. T. Steenstra
A multstatic frequency-modulated continuous wave (FMCW) radar system is under development for use in the control system of autonomous vehicles. The aim of the system, named Colarado, is the 3D location of obstacles in the surrounding environment. In this paper a laboratory prototype system version, the demonstrator, is described and current results are presented.
Radar Studies in the Solar System
NASA Technical Reports Server (NTRS)
Shaprio, Irwin I.
We aid in study of the solar system by means of ground-based radar. We have concentrated on: (1) developing the ephemerides needed to acquire radar data at Arecibo Observatory and (2) analyzing the resultant data to: test fundamental laws of gravitation; determine the size , shape, topography, and spin vectors of the targets; and study the surface properties of these objects, through their scattering law and polarization characteristics. We are engaged in radar observations of asteroids and comets, both as systematically planned targets and as "targets of opportunity." In the course of the program, we have prepared ephemerides for about 80 asteroids and three comets, and the radar observations have been made or attempted at the Arecibo Observatory, in most cases successfully, and in some cases on more than one apparition. The results of these observations have included echo spectra for the targets and, in some cases, delay - Doppler images and measurements of the total round-trip delay to the targets. Perhaps the most dramatic of these results are the images obtained for asteroids (4179) Toutatis and 1989PB (Castalia), which were revealed to be double-lobed objects by the radar images. Besides these direct results, the radar observations have furnished information on the sizes and shapes of the targets through analysis of the Doppler width of the echoes as a function of time, and on the surface properties (such as composition, bulk density, and roughness) through analysis of the reflectivity and of the polarization state of the echoes. We have also refined the orbits of the observed asteroids as a result of the Doppler (and in some cases delay) measurements from the radar observations. Although the orbits of main-belt asteroids accessible to ground-based radar are quite well known from the available optical data, some near-Earth objects have been seen by radar very soon after their optical discovery (for example, 199OMF, just eight days after discovery). In such cases. the radar results ensure that the object in question can be anticipated and identified at the next apparition. We have also participated in radar studies of the terrestrial planets. The results of these studies have included both planetary topography profiles from the analysis of round-trip delays to points along the target Doppler equator and determinations of the target spin state. The latter is of special interest in the case of Venus, which is very close to, but not on, a multi-body spin-orbit resonance such that Venus rotates 12 times for every 8 Earth orbits and 13 Venus orbits. As a result, Venus presents nearly the same face toward Earth at each inferior conjunction. Our latest results confirm that the spin state of Venus is slightly off the resonance. The delay measurements from planetary 2 ranging have also been used in combination with other types of range data in testing general relativity with increasing accuracy. We have also been engaged in radar studies of planetary satellites. Using our ephemerides, Arecibo made radar observations of the Galilean satellites of Jupiter and of Mars' satellite Phobos during the favorable opposition seasons (1988-1992 for Jupiter and 1990 for Mars). An attempt was also made to observe Deimos, but without detecting an echo. In 1997, an attempt was made to observe Saturn's satellite Titan, using the newly upgraded Arecibo radar system for transmitting and the Goldstone radar for receiving, but no echo was detected. The study of satellites by radar is in many ways similar to that of asteroids. The results from these observations have included characterization of the surface properties from the reflectivity and polarization ratio, as well as (in the case of the large satellites of Jupiter) the variation of reflectivity with incidence angle.
Urban Flood Warning Systems using Radar Technologies
NASA Astrophysics Data System (ADS)
Fang, N.; Bedient, P. B.
There have been an increasing number of urban areas that rely on weather radars to provide accurate precipitation information for flood warning purposes. As non-structural tools, radar-based flood warning systems can provide accurate and timely warnings to the public and private entities in urban areas that are prone to flash floods. The wider spatial and temporal coverage from radar increases flood warning lead-time when compared to rain and stream gages alone. The Third Generation Rice and Texas Medical Center (TMC) Flood Alert System (FAS3) has been delivering warning information with 2 to 3 hours of lead time and a R2 value of 93% to facility personnel in a readily understood format for more than 50 events in the past 15 years. The current FAS utilizes NEXRAD Level II radar rainfall data coupled with a real-time hydrologic model (RTHEC-1) to deliver warning information. The system has a user-friendly dashboard to provide rainfall maps, Google Maps based inundation maps, hydrologic predictions, and real-time monitoring at the bayou. This paper will evaluate its reliable performance during the recent events occurring in 2012 and 2013 and the development of a similar radar-based flood warning system for the City of Sugar Land, Texas. Having a significant role in the communication of flood information, FAS marks an important step towards the establishment of an operational and reliable flood warning system for flood-prone urban areas.
Radar Performance Improvement. Angle Tracking Modification to Fire Control Radar System for Space Shuttle Rendezvous
NASA Technical Reports Server (NTRS)
Little, G. R.
The AN/APQ-153 fire control radar modified to provide angle tracking was evaluated for improved performance. The frequency agile modifications are discussed along with the range-rate improvement modifications, and the radar to computer interface. A parametric design and comparison of noncoherent and coherent radar systems are presented. It is shown that the shuttle rendezvous range and range-rate requirements can be made by a Ku-Band noncoherent pulse radar.
The instrumental principles of MST radars and incoherent scatter radars and the configuration of radar system hardware
NASA Technical Reports Server (NTRS)
Roettger, Juergen
The principle of pulse modulation used in the case of coherent scatter radars (MST radars) is discussed. Coherent detection and the corresponding system configuration is delineated. Antenna requirements and design are outlined and the phase-coherent transmitter/receiver system is described. Transmit/receive duplexers, transmitters, receivers, and quadrature detectors are explained. The radar controller, integrator, decoder and correlator design as well as the data transfer and the control and monitoring by the host computer are delineated. Typical operation parameters of some well-known radars are summarized.
Three-channel processing for improved geo-location performance in SAR-based GMTI interferometry
NASA Astrophysics Data System (ADS)
Deming, Ross W.; MacIntosh, Scott; Best, Matthew
This paper describes a method for accurately geo-locating moving targets using three-channel SAR-based GMTI interferometry. The main goals in GMTI processing are moving target detection and geo-location. In a 2011 SPIE paper we showed that reliable target detection is possible using two-channel interferometry, even in the presence of main-beam clutter. Unfortunately, accurate geo-location is problematic when using two-channel interferometry, since azimuth estimation is corrupted by interfering clutter. However, we show here that by performing three-channel processing in an appropriate sequence, clutter effects can be diminished and significant improvement can be obtained in geo-location accuracy. The method described here is similar to an existing technique known as Clutter Suppression Interferometry (CSI), although there are new aspects of our implementation. The main contribution of this paper is the mathematical discussion, which explains in a straightforward manner why three-channel CSI outperforms standard two-channel interferometry when target signatures are embedded in main-beam clutter. Also, to our knowledge this paper presents the first results of CSI applied to the Gotcha Challange data set, collected using an X-band circular SAR system in an urban environment.
Local early warning systems with LS-radar
Erik Arvidsson
A complement to the local optical early warning system is described. The LS system (LS = optical early warning station) is suggested, using simple marine radars equipped with MTI circuits. It is possible for land based MTI-radar to separate moving target echoes from ground echoes. The LS-radar early warning system gives directly a warning to neighboring local command centers. Advantages
System capability of air traffic control radar beacon system
N. K. Shaw; A. A. Simolunas
The air traffic control radar beacon system problems and solutions to these problems are discussed. Residual problems, their extent, and their impact on future systems are described. The results of a system model are related to the possible fixes.
Ground penetrating radar data acquisition system
Robert Beck; Jay Cosentino; David W. Collier; Jim Osborn
Carnegie Mellon University is automating the use of Ground Penetrating Radar (GPR) for cleanup of hazardous waste sites. The Site Investigation Robot (SIR) project at the Field Robotics Center is applying robotics and image processing technologies to the investigatory phase of these waste site cleanups. The current focus is on the development of an automated subsurface mapping system to locate
Moving target localization with multistatic radar systems
P. F. Sammartino; C. J. Baker; M. Rangaswamy
In this paper we describe a method of processing data from a chosen area as surveyed by a multistatic system for the localization of a target. For this purpose data were acquired using the UCL netted radar and processed with two different incoherent approaches for localizing the target on a grid. The first is a centralized scheme and the second
Tracking system for photon-counting laser radar
Chang, Joshua TsuKang
The purpose of this thesis is to build the tracking system for a photon-counting laser radar specifically a laser radar that has the ability to perform direct and coherent detection measurement at low signal levels with ...
MIMO radar systems Permanent members: F. Nadal, P. Jardin.
Baudoin, Genevi�ve
MIMO radar systems Permanent members: F. Nadal, P. Jardin. Associated researcher: S. Middleton. Multiple-input and multiple-output (MIMO) radar systems use arrays of transmitting and receiving antennas like phased array radars but while a phased array transmits highly correlated signals which form a beam
RADAR SYSTEMS FOR INFRASTRUCTURES DIAGNOSTICS: A REVIEW Ilaria Catapano, Antonio Affinito, Lorenzo Crocco, Francesco Soldovieri
Paris-Sud XI, Universit� de
RADAR SYSTEMS FOR INFRASTRUCTURES DIAGNOSTICS: A REVIEW Ilaria Catapano, Antonio Affinito, Lorenzo assessing the reconstruction capabilities of two different radar systems for subsurface imaging and civil engineering monitoring and diagnostics. In fact, Ground Penetrating Radar and Holographic Radar are well
Lincoln Laboratory millimeter-wave synthetic aperture radar imaging system
John C. Henry; Thomas J. Murphy; Kathleen M. Carusone
The Lincoln Laboratory millimeter-wave synthetic aperture radar (SAR) imaging system is part of a DARPA-funded program that was established at Lincoln Laboratory to investigate the detection and classification of stationary targets using ultra-high resolution, fully polarimetric SAR and real aperture radar (RAR) data. The system consists of an airborne radar that operates at 33.56 GHz. The raw radar data are
Twin VHF radar for european space situation awareness system
Istvan Balajti
The efficient space surveillance system in the current state of radar technology must be addressed in a cost-effective way. Consequently, a new twin VHF band radar concept with increased technical capabilities could partially take over these challenges. This article would like to draw the reader's attention to the potential benefits of VHF radar signal fusion, which can be extended for
The SIR-C\\/X-SAR Synthetic Aperture Radar system
R. L. Jordan; B. L. Huneycutt; M. Werner
The Spaceborne Imaging Radar-C\\/X-Band Synthetic Aperture Radar (SIR-C\\/X-SAR) was a joint United States\\/German\\/Italian space agency imaging radar system successfully flown aboard the shuttle Endeavor in April 1994 and again in September\\/October 1994. The multifaceted SIR-C\\/X-SAR represents a major technological step forward in radar remote sensing and is the first spaceborne multifrequency, polarimetric SAR. The United States developed SIR-C operated at
Scanning laser radar system for rendezvous and docking in space
NASA Astrophysics Data System (ADS)
Saito, Hirobumi; Nakatani, Ichiro; Ninomiya, Keiken; Furuya, Akira
A scanning laser radar system for rendezvous and docking in space is being developed. This laser radar system will be utilized in an autonomous satellite retrieval experiment which is planned as one of the future missions to be conducted on Japanese Space Flyer Unit (SFU) in 1990s. Rendezvous and retrieval operation will be automatically performed by on-board instruments. The laser radar system performs ranging, tracking, as well as attitude determination in short range.
Detecting and mitigating wind turbine clutter for airspace radar systems.
Wang, Wen-Qin
It is well recognized that a wind turbine has a large radar cross-section (RCS) and, due to the movement of the blades, the wind turbine will generate a Doppler frequency shift. This scattering behavior may cause severe interferences on existing radar systems including static ground-based radars and spaceborne or airborne radars. To resolve this problem, efficient techniques or algorithms should be developed to mitigate the effects of wind farms on radars. Herein, one transponder-based mitigation technique is presented. The transponder is not a new concept, which has been proposed for calibrating high-resolution imaging radars. It modulates the radar signal in a manner that the retransmitted signals can be separated from the scene echoes. As wind farms often occupy only a small area, mitigation processing in the whole radar operation will be redundant and cost inefficient. Hence, this paper uses a transponder to determine whether the radar is impacted by the wind farms. If so, the effects of wind farms are then mitigated with subsequent Kalman filtering or plot target extraction algorithms. Taking airborne synthetic aperture radar (SAR) and pulse Doppler radar as the examples, this paper provides the corresponding system configuration and processing algorithms. The effectiveness of the mitigation technique is validated by numerical simulation results. PMID:24385880
The representation of moving targets in multi-channel UWB SAR images and it�s application in the generalization of image domain GMTI methods
Yu-lin Chang; Hong Zhou; Xiao-tao Huang; Zhi-min Zhou
To generalize the image domain GMTI methods for slow moving targets to be suitable for detection fast moving targets with multi-channel ultra-wide band (UWB) SAR system, the representation of moving targets in multi-channel UWB SAR images is studied in this paper. By analyzing the local back projection (LBP) SAR imaging process for the moving target, this paper gives the analytic
An integrated radar imaging system for the STAR2 aircraft
B. Akam; R. Deane; M. Sartori; R. Lowry; B. Mercer
A commercial lightweight, real-time digital synthetic-aperture radar (SAR) known as STAR-2 (sea-lice and terrain assessment radar) is described. The SAR system consists of the MacDonald Dettwiler integrated radar imaging system (IRIS) and is carried aboard a small executive twin-turboprop aircraft. The IRIS makes extensive use of digital electronics to provide data of high radiometric and geometric quality, in real time.
Multi-Antenna Radar Systems for Doppler Rain Measurements
NASA Technical Reports Server (NTRS)
Durden, Stephen; Tanelli, Simone; Siqueira, Paul
Use of multiple-antenna radar systems aboard moving high-altitude platforms has been proposed for measuring rainfall. The basic principle of the proposed systems is a variant of that of along-track interferometric synthetic-aperture radar systems used previously to measure ocean waves and currents.
Hybrid array architectures for BMD radar systems
J. Frank; J. D. Richards; A. Agrawal
The proliferation of long range ballistic missiles has increased the need for radars capable of supporting early midcourse and ascent phase intercepts. In order to support these early midcourse and ascent phase intercepts, the ballistic missile defense (BMD) radar should be forward deployed. While a sea-based capability can be forward deployed, an easily transportable ground-based radar would be advantageous in
47 CFR 15.515 - Technical requirements for vehicular radar systems.
Code of Federal Regulations, 2010 CFR
... Technical requirements for vehicular radar systems. 15.515 Section 15.515... Technical requirements for vehicular radar systems. (a) Operation under... (b) The UWB bandwidth of a vehicular radar system operating under the...
47 CFR 15.515 - Technical requirements for vehicular radar systems.
Code of Federal Regulations, 2011 CFR
... Technical requirements for vehicular radar systems. 15.515 Section 15.515... Technical requirements for vehicular radar systems. (a) Operation under... (b) The UWB bandwidth of a vehicular radar system operating under the...
Southwest PAVE PAWS radar system: Environmental assessment
NASA Astrophysics Data System (ADS)
Everett, S. J.; Edson, W. A.; Heynick, L. N.; Pierce, S. R.; Shepherd, R. A.; Wlaklet, T. H.
This document describes the probable environmental impacts of constructing and operating a new surveillance and tracking radar that would operate between 420 and 450 MHz. Four candidate sites in the vicinity of Goodfellow Air Force Base were considered. The impact analysis found that chronic exposure of humans to the radiofrequency radiation levels outside the exclusion fence is not likely to be harmful. No hazards would be associated with fuel handling or cardiac pacemakers at ground level beyond the exclusion fence. Interference with TV reception and other home electronic systems and with UHF land mobile and amateur radios is possible, depending on the site. Handling and use of electro-explosive devices (EEDs) would be safe beyond about 1.2 miles for the basic system and about 2.4 miles for the optional, higher power system. Electromagnetic interference with radar altimeters, air navigation, and air-ground communication is not likely except at two candidate sites, where interference and EED and pacemaker hazards may exist for aircraft operating into or out of a nearby landing strip. No significant adverse biophysical impacts are expected in any location.
Radar systems for a polar mission, volume 1
NASA Technical Reports Server (NTRS)
Moore, R. K.; Claassen, J. P.; Erickson, R. L.; Fong, R. K. T.; Komen, M. J.; Mccauley, J.; Mcmillan, S. B.; Parashar, S. K.
The application of synthetic aperture radar (SAR) in monitoring and managing earth resources is examined. Synthetic aperture radars form a class of side-looking airborne radar, often referred to as coherent SLAR, which permits fine-resolution radar imagery to be generated at long operating ranges by the use of signal processing techniques. By orienting the antenna beam orthogonal to the motion of the spacecraft carrying the radar, a one-dimensional imagery ray system is converted into a two-dimensional or terrain imaging system. The radar's ability to distinguish - or resolve - closely spaced transverse objects is determined by the length of the pulse. The transmitter components receivers, and the mixer are described in details.
A SEASAT-A synthetic aperture imaging radar system
NASA Technical Reports Server (NTRS)
Jordan, R. L.; Rodgers, D. H.
The SEASAT, a synthetic aperture imaging radar system is the first radar system of its kind designed for the study of ocean wave patterns from orbit. The basic requirement of this system is to generate continuous radar imagery with a 100 km swath with 25m resolution from an orbital altitude of 800 km. These requirements impose unique system design problems. The end to end data system described including interactions of the spacecraft, antenna, sensor, telemetry link, and data processor. The synthetic aperture radar system generates a large quantity of data requiring the use of an analog link with stable local oscillator encoding. The problems associated in telemetering the radar information with sufficient fidelity to synthesize an image on the ground is described as well as the selected solutions to the problems.
Scanning laser radar system for rendezvous and docking in space
Hirobumi Saito; Ichiro Nakatani; Keiken Ninomiya; Akira Furuya
A scanning laser radar system for rendezvous and docking in space is being developed. This laser radar system will be utilized in an autonomous satellite retrieval experiment which is planned as one of the future missions to be conducted on Japanese Space Flyer Unit (SFU) in 1990s. Rendezvous and retrieval operation will be automatically performed by on-board instruments. The laser
ISAR imaging using an emulated multistatic radar system
J. Palmer; J. H omer; I. D. Longstaff; M. Martorella; B. Littleton
The use of a monostatic radar configuration limits the ability of an inverse synthetic aperture radar (ISAR) system to image targets in certain geometries. By employing multistatic geometries this limitation may be overcome. This paper discusses the emulation of multistatic geometries, via sea surface multipath reflections, using a monostatic system. This application capitalises on the advantages provided by both monostatic
Recent Breakthroughs in RF Photonics for Radar Systems
K. Garenaux; T. Merlet; M. Alouini; J. Lopez; N. Vodjdani; R. Boula-Picard; C. Fourdin; J. Chazelas
Radar systems require transmission of very high purity signals. Photonics is now mature enough to achieve analog transmission with very low noise, strong immunity, and wide-bandwidth even in harsh environments. We present our recent developments of optimized optical links dedicated to radar and multifunction systems
Can OTH Radar Help Tsunami Warning Systems ?
NASA Astrophysics Data System (ADS)
Coisson, P.; Occhipinti, G.; Roland, L.; Lognonn�, P.
A series of ionospheric anomalies following the Sumatra tsunami has been reported in the scientific literature (e.g., Liu et al. 2006; DasGupta et al. 2006; Occhipinti et al. 2006). Similar anomalies were also observed after the tsunamigenic earthquake in Peru in 2001 (Artru et al., 2005) and after the recent earthquakes in Sumatra and Chile in 2007. All these anomalies show the signature in the ionosphere of tsunami-generated internal gravity waves (IGW) propagating in the neutral atmosphere over oceanic regions. Most of these ionospheric anomalies are deterministic and reproducible by numerical modeling (Occhipinti et al., 2006, 2008) via the ocean/neutral atmosphere/ionosphere coupling mechanism. In addition, the numerical modeling supplies useful helps in the estimation of expected anomalies to explore and identify new techniques to detect the tsunami signature in the ionosphere, other then GPS and altimeters. Here we present an overview of the physical coupling mechanism highlighting the advantage of OTH radar in the tsunami detection by ionospheric sounding. The large coverage of OTH radar and its sensitivity to plasma anomalies can open new perspectives in the future oceanic monitoring and tsunami warning system. [Artru et al., 2005] Geophys. J. Int., 160, 2005 [DasGupta et al., 2006] Earth Planet. Space, 35, 929-959. [Liu et al., 2006] J. Geophys. Res., 111, A05303. [Occhipinti et al., 2006] Geophys. Res. Lett., 33, L20104, 2006 [Occhipinti et al., 2008] Geophys. J. Int., 173, 3, 753-1135, 2008.
A very wide frequency band pulsed/IF radar system
NASA Technical Reports Server (NTRS)
Jones, D. N.; Burnside, W. D.
A pulsed/IF radar for compact range radar cross section measurements has been developed which converts RF returns to a fixed IF, so that amplification and grating may be performed at one frequency. This permits the use of components which have optimal performance at this frequency which results in a corresponding improvement in performance. Sensitivity and dynamic range are calculated for this system and compared with our old radar, and the effect of pulse width on clutter level is also studied. Sensitivity and accuracy tests are included to verify the performance of the radar.
The Goldstone Solar System Radar: 1988-2003 Earth-based Mars Radar Observations
NASA Technical Reports Server (NTRS)
Haldemann, A. F. C.; Jurgens, R. F.; Slade, M. A.; Larsen, K. W.
The Goldstone Solar System Radar (GSSR) has successfully collected radar echo data from Mars over the past 30 years. The older data provided local elevation information for Mars, along with radar scattering information with global resolution. Since the upgrade to the 70-m DSN antenna at Goldstone completed in 1986, Mars data has been collected during all but the 1997 Mars opposition. Radar data, and non-imaging delay- Doppler data in particular, requires significant data processing to extract elevation, reflectivity and roughness of the reflecting surface. The spatial resolution of these experiments is typically some 10 km in longitude by some 150 km in latitude. The interpretation of these parameters while limited by the complexities of electromagnetic scattering, do provide information directly relevant to geophysical and geomorphic analyses of Mars.
Signal processing and waveform selection strategies in multistatic radar systems
Ivan Bradaric; Gerard T. Capraro; Michael C. Wicks; Peter Zulch
The multistatic ambiguity function has recently been used as a tool for analyzing multistatic radar systems. It was demonstrated that the multistatic ambiguity function with proper analytical foundation and corresponding graphic representation can serve as a guideline for developing multistatic radar signal processing rules. In this work we use this newly developed approach to combine optimal selection of weights for
Tracking function in bistatic and multistatic radar systems
A. Farina
The paper presents a unified view of the tracking algorithms available for multistatic radar systems. The first topic considered is the derivation of tracking algorithms for bistatic radar. Different algorithms can be conceived according to different sets of measurements which may be processed (e.g., the range sum and one angle, or two angles). Mean and standard deviation values of tracking
29. Perimeter acquisition radar building room #318, data processing system ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
29. Perimeter acquisition radar building room #318, data processing system area; data processor maintenance and operations center, showing data processing consoles - Stanley R. Mickelsen Safeguard Complex, Perimeter Acquisition Radar Building, Limited Access Area, between Limited Access Patrol Road & Service Road A, Nekoma, Cavalier County, ND
Noninvasive biosignal detection radar system using circular polarization.
Lee, Jee-Hoon; Hwang, Jung Man; Choi, Dong Hyuk; Park, Seong-Ook
This paper proposes an integrated hypersensitive Doppler radar system through a circular polarization characteristic. Through the idea of a reverse sense of rotation when the reflecting surface is perfectly conducting, it is shown that the detecting property of the system can be effectively improved by using antennas that have a reverse polarization. This bistatic radar system can be used in noninvasively sensing biosignals such as respiration and heart rates with the periodic movement of skin and muscle near the heart. The operating frequency of the system is in the X-band and the radar size is 95 x50 x13 mm(3). PMID:19369168
The Apollo lunar sounder radar system
LEONARD J. PORCELLO; R. L. Jordan; JERRY S. ZELENKA; GARY F. ADAMS; ROGER J. PHILLIPS; WALTER E. BROWN; S. H. Ward; P. L. Jackson
The objectives of the Apollo 17 Lunar Sounder Experiment (ALSE) were to detect subsurface geologic structures, to generate a continuous lunar profile, and to image the moon a radar wavelengths. The first objective is generally impossible on Earth, but is possible on the moon because of the very low EM attenuation found in lunar rocks. A three-wavelength synthetic-aperture radar (SAR)
The 3D laser radar vision processor system
NASA Technical Reports Server (NTRS)
Sebok, T. M.
Loral Defense Systems (LDS) developed a 3D Laser Radar Vision Processor system capable of detecting, classifying, and identifying small mobile targets as well as larger fixed targets using three dimensional laser radar imagery for use with a robotic type system. This processor system is designed to interface with the NASA Johnson Space Center in-house Extra Vehicular Activity (EVA) Retriever robot program and provide to it needed information so it can fetch and grasp targets in a space-type scenario.
Advanced Meteor radar at Tirupati: System details and first results
NASA Astrophysics Data System (ADS)
Sunkara, Eswaraiah; Gurubaran, Subramanian; Sundararaman, Sathishkumar; Venkat Ratnam, Madineni; Karanam, Kishore Kumar; Eethamakula, Kosalendra; Vijaya Bhaskara Rao, S.
An advanced meteor radar viz., Enhanced Meteor Detection Radar (EMDR) operating at 35.25 MHz is installed at Sri Venkateswara University (SVU), Tirupati (13.63oN, 79.4oE), India, in the month of August 2013. Present communication describes the need for the meteor radar at present location, system description, its measurement techniques, its variables and comparison of measured mean winds with contemporary radars over the Indian region. The present radar site is selected to fill the blind region of Gadanki (13.5oN, 79.2oE) MST radar, which covers mesosphere and lower thermosphere (MLT) region (70-110 km). By modifying the receiving antenna structure and elements, this radar is capable of providing accurate wind information between 70 and 110 km unlike other similar radars. Height covering region is extended by increasing the meteor counting capacity by modifying the receiving antenna structure and elements and hence its wind estimation limits extended below and above of 80 and 100 km, respectively. In the present study, we also made comparison of horizontal winds in the MLT region with those measured by similar and different (MST and MF radars) techniques over the Indian region including the model (HWM 07) data sets. The comparison showed a very good agreement between the overlapping altitudes (82-98 km) of different radars. Zonal winds compared very well as that of meridional winds. The observed discrepancies and limitations in the wind measurement are discussed. This new radar is expected to play important role in understanding the vertical and lateral coupling by forming a unique local network.
Low frequency radar systems should replace current high frequency radar systems on the battlefield to optimize the army's ground surveillance radar capability
P. H. M. Labay III
Current state-of-the-art technology provides the Army with two distinct types of radar to accomplish the ground surveillance mission. The first is a high frequency, line-of-sight system; the second is a low frequency, foliage independent system. To optimize its future ground surveillance radar capability, the Army must, in light of monetary and manpower constraints, choose that system which best fulfills its
A land based radar polarimeter processing system�
Kronke, Chester William
Operations Utility Package. 64 CHAPTER I PROJECT BACKGROUND The Remote Sensing Center (RSC) at Texas ARM University was con- tracted by NASA Goddard Space Flight Center to design, build, and put into operation a mobile land based radar polarimeter [I...
The EISCAT Svalbard radar: A case study in modern incoherent scatter radar system design
NASA Astrophysics Data System (ADS)
Wannberg, G.; Wolf, I.; Vanhainen, L.-G.; Koskenniemi, K.; R�Ttger, J.; Postila, M.; Markkanen, J.; Jacobsen, R.; Stenberg, A.; Larsen, R.; Eliassen, S.; Heck, S.; Huuskonen, A.
The EISCAT (European incoherent scatter) Svalbard radar (ESR) was officially inaugurated on August 22, 1996. This event marked the successful completion on schedule of the first phase of the EISCAT Svalbard radar project. In contrast to previous incoherent scatter radars, the ESR system design was adapted to make use of commercial off-the-shelf TV transmitter hardware, thereby reducing design risk, lead times, and cost to a minimum. Commercial hardware is also used in the digital signal processing system. Control and monitoring are performed by distributed, networked VME systems. Thanks to modern reflector antenna design methods and extreme efforts to reduce the receiver noise contribution, the system noise temperature is only 70 K, thus making the ESR about 30% faster than the much more powerful EISCAT UHF radar in F region experiments! Once the transmitter power is increased to 1 MW, it will become about 2-3 times faster than the UHF radar. State-of-the-art exciter and receiver hardware has been developed in-house to accommodate the special requirements introduced by operating the radar at the exceptionally high duty cycle of 25%. The RF waveform is generated by a system based on four switchable direct digital synthesizers. Continuous monitoring of the transmitted RF waveform by the receiver system allows removal of klystron-induced spurious Doppler effects from the data. Intermediate-frequency sampling at 7.5 MHz is employed, followed by fully digital channel separation, signal detection, and postdetection filtering in six parallel receiver channels. Radar codes for both E and F layer observation have been designed and perfected. So far, more than 40 hours of good quality ionospheric data have been collected and analyzed in terms of plasma parameters. While the tragic loss of the Cluster mission suddenly changed the plans and dispositions of a majority of the ESR user community, the radar has still been in high demand since its inauguration. It is now being operated by EISCAT staff on a campaign basis, to provide ground-based support data for a number of other magnetospheric satellites, notably Polar and FAST, and will be opened to the EISCAT user community for special program operations later in 1997.
Reconfigurable data acquisition system for weather radar applications
Rishi Khasgiwale; Luko Krnan; Atchuthan Perinkulam; Russell Tessier
Tornado, hazardous weather and flood detection radars demand high-throughput, high-speed data acquisition and processing. Weather-processing systems need to be capable of implementing powerful signal processing algorithms on the raw data collected by the radars. Following processing, data is distributed to the end-user in real-time for timely and accurate detection of imminent weather disasters. Since physical accessibility to such systems is
Adaptive space-time processing for interference suppression in phased array radar systems. I. Search radar
H. H. M. Ghouz; F. I. A. Elghany; M. M. Qutb
This paper presents an adaptive technique of filtering to suppress the interference in phased array search radar systems. This interference includes noise, clutter, and jamming signals. Unlike the time processing techniques, our filtering process is based upon the target Doppler shift as well as the interference spatial distribution to suppress adaptively the undesired signals. This can be achieved by estimating
Minimum Detectable Radar Signal and Its Dependence upon Parameters of Radar Systems
A. V. Haeff
This paper presents results of an early study of the influence of parameters of a pulse radar system on its sensitivity. More specifically, it describes an experimental determination of the absolute value of minimum pulse signal visually detectable through random noise with a probability of 50 per cent for a wide range of the following parameters: pulse-repetition rate r, pulse
Ziv -Zakai Lower Bound on Target Localization Estimation in MIMO Radar Systems
Haimovich, Alexander
Ziv - Zakai Lower Bound on Target Localization Estimation in MIMO Radar Systems Vlad M. Chiriac) for the localization problem in a MIMO radar system. The target is positioned in the near-field of a network of radars of arbitrary geometry. The radars have ideal mutual time and phase synchronization. The target location
The Apollo Lunar Sounder radar system
NASA Technical Reports Server (NTRS)
Porcello, L. J.; Zelenka, J. S.; Adams, G. F.; Jackson, P. L.; Jordan, R. L.; Phillips, R. J.; Brown, W. E., Jr.; Ward, S. H.
The objectives of the Apollo 17 Lunar Sounder Experiment (ALSE) were to detect subsurface geologic structures, to generate a continuous lunar profile, and to image the moon at radar wavelengths. A three-wavelength synthetic-aperture radar (SAR) operating at 60, 20, and 2 m wavelengths was designed to attain these objectives. The design choices reflected a balance of scientific requirements versus Apollo mission and hardware constraints. The radar data from the lunar mission were recorded on photographic film in a conventional SAR format, and were returned to earth for processing. A combination of optical and digital processing and exploitation techniques was applied to the scientific interpretation of the data. Some preliminary results from the lunar mission have been obtained.
Spaceborne Doppler Precipitation Radar: System Configurations and Performance Analysis
NASA Technical Reports Server (NTRS)
Tanelli, Simone; Im, Eastwood
Knowledge of the global distribution of the vertical velocity of precipitation is important in in the study of energy transportation in the atmosphere, the climate and weather. Such knowledge can only be directly acquired with the use of spaceborne Doppler precipitation radars. Although the high relative speed of the radar with respect to the rainfall particles introduces significant broadening in the Doppler spectrum, recent studies have shown that the average vertical velocity can be measured to acceptable accuracy levels by appropriate selection of radar parameters. Furthermore, methods to correct for specific errors arising from NUBF effects and pointing uncertainties have recently been developed. In this paper we will present the results of the trade studies on the performances of a spaceborne Doppler radar with different system parameters configurations.
The Seasat-A synthetic aperture radar system
NASA Astrophysics Data System (ADS)
Jordan, R. L.
The paper discusses the Seasat-A synthetic aperture radar system (SAR). The objective of this system was to detect ocean waves from orbital altitudes. A SAR system operating at 1275 MHz was designed to meet this objective; the choice of wavelength resulted from the imagery obtained by aircraft during 1972 to 1974 and the ease of implementation. The Seasat-A SAR system was turned-on in orbit on July 4, 1978, and gathered imagery until the spacecraft bus failed in orbit in Oct. 1978. The hardware including the antenna, the radar sensor, and data-link subsystem, and the SAR data processing subsystem are described; the radar performance including the SAR system error budget and various SAR imageries are presented, concluding that the performance of the Seasat-A SAR system met all of its parameters on at least some of the imagery.
Ultrawideband imaging radar based on OFDM: system simulation analysis
NASA Astrophysics Data System (ADS)
Garmatyuk, Dmitriy
Orthogonal frequency division-multiplexing (OFDM) is rapidly emerging as a preferred method of UWB signaling in commercial applications aimed mainly at low-power, high data-rate communications. This paper explores the possibility of applying OFDM to use in imaging radar technology. Ultra-wideband nature of the signal provides for high resolution of the radar, whereas usage of multi-sub-carrier method of modulation allows for dynamic spectrum allocation. Robust multi-path performance of OFDM signals and heavy reliance of transceiver design on digital processors easily implemented in modern VLSI technology make a number of possible applications viable, e.g.: portable high-resolution indoor radar/movement monitoring system; through-the-wall/foliage synthetic aperture imaging radar with a capability of image transmission/broadcasting, etc. Our work is aimed to provide a proof-of-concept simulation scenario to explore numerous aspects of UWB-OFDM radar imaging through evaluating range and cross-range imaging performance of such a system with an eventual goal of software-defined radio (SDR) implementation. Stripmap SAR topology was chosen for modeling purposes. Range/cross-range profiles were obtained along with full 2-D images for multi-target in noise scenarios. Model set-up and results of UWB-OFDM radar imaging simulation study using Matlab/Simulink modeling are presented and discussed in this paper.
Southwest PAVE PAWS radar system: Environmental assessment
S. J. Everett; W. A. Edson; L. N. Heynick; S. R. Pierce; R. A. Shepherd; T. H. Wlaklet
This document describes the probable environmental impacts of constructing and operating a new surveillance and tracking radar that would operate between 420 and 450 MHz. Four candidate sites in the vicinity of Goodfellow Air Force Base were considered. The impact analysis found that chronic exposure of humans to the radiofrequency radiation levels outside the exclusion fence is not likely to
Bistatic radar sea state monitoring system design
NASA Technical Reports Server (NTRS)
Ruck, G. T.; Krichbaum, C. K.; Everly, J. O.
Remote measurement of the two-dimensional surface wave height spectrum of the ocean by the use of bistatic radar techniques was examined. Potential feasibility and experimental verification by field experiment are suggested. The required experimental hardware is defined along with the designing, assembling, and testing of several required experimental hardware components.
Review of the NASA\\/JPL airborne synthetic aperture radar system
Yunling Lou
AIRSAR has served as a test-bed for both imaging radar techniques and radar technologies for over a decade. In fact, the polarimetric, cross-track interferometric, and along-track interferometric radar techniques were all developed using AIRSAR. We present the up-to-date system configuration, the expected performance and data accuracy in the standard radar modes.
Development of land based radar polarimeter processor system
NASA Technical Reports Server (NTRS)
Kronke, C. W.; Blanchard, A. J.
The processing subsystem of a land based radar polarimeter was designed and constructed. This subsystem is labeled the remote data acquisition and distribution system (RDADS). The radar polarimeter, an experimental remote sensor, incorporates the RDADS to control all operations of the sensor. The RDADS uses industrial standard components including an 8-bit microprocessor based single board computer, analog input/output boards, a dynamic random access memory board, and power supplis. A high-speed digital electronics board was specially designed and constructed to control range-gating for the radar. A complete system of software programs was developed to operate the RDADS. The software uses a powerful real time, multi-tasking, executive package as an operating system. The hardware and software used in the RDADS are detailed. Future system improvements are recommended.
A fully photonics-based coherent radar system.
Ghelfi, Paolo; Laghezza, Francesco; Scotti, Filippo; Serafino, Giovanni; Capria, Amerigo; Pinna, Sergio; Onori, Daniel; Porzi, Claudio; Scaffardi, Mirco; Malacarne, Antonio; Vercesi, Valeria; Lazzeri, Emma; Berizzi, Fabrizio; Bogoni, Antonella
The next generation of radar (radio detection and ranging) systems needs to be based on software-defined radio to adapt to variable environments, with higher carrier frequencies for smaller antennas and broadened bandwidth for increased resolution. Today's digital microwave components (synthesizers and analogue-to-digital converters) suffer from limited bandwidth with high noise at increasing frequencies, so that fully digital radar systems can work up to only a few gigahertz, and noisy analogue up- and downconversions are necessary for higher frequencies. In contrast, photonics provide high precision and ultrawide bandwidth, allowing both the flexible generation of extremely stable radio-frequency signals with arbitrary waveforms up to millimetre waves, and the detection of such signals and their precise direct digitization without downconversion. Until now, the photonics-based generation and detection of radio-frequency signals have been studied separately and have not been tested in a radar system. Here we present the development and the field trial results of a fully photonics-based coherent radar demonstrator carried out within the project PHODIR. The proposed architecture exploits a single pulsed laser for generating tunable radar signals and receiving their echoes, avoiding radio-frequency up- and downconversion and guaranteeing both the software-defined approach and high resolution. Its performance exceeds state-of-the-art electronics at carrier frequencies above two gigahertz, and the detection of non-cooperating aeroplanes confirms the effectiveness and expected precision of the system. PMID:24646997
Fiber optic coherent laser radar 3D vision system
NASA Astrophysics Data System (ADS)
Sebastian, Richard L.; Clark, Robert B.; Simonson, Dana L.; Slotwinski, Anthony R.
Recent advances in fiber optic component technology and digital processing components have enabled the development of a new 3D vision system based upon a fiber optic FMCW coherent laser radar. The approach includes a compact scanner with no moving parts capable of randomly addressing all pixels. The system maintains the immunity to lighting and surface shading conditions which is characteristic of coherent laser radar. The random pixel addressability allows concentration of scanning and processing on the active areas of a scene, as is done by the human eye-brain system.
Fiber optic coherent laser radar 3d vision system
Sebastian, R.L.; Clark, R.B.; Simonson, D.L. [and others
Recent advances in fiber optic component technology and digital processing components have enabled the development of a new 3D vision system based upon a fiber optic FMCW coherent laser radar. The approach includes a compact scanner with no moving parts capable of randomly addressing all pixels. The system maintains the immunity to lighting and surface shading conditions which is characteristic of coherent laser radar. The random pixel addressability allows concentration of scanning and processing on the active areas of a scene, as is done by the human eye-brain system.
An automated radar-signature measurement system
Juergen Kruse
The design and operation of an automated measurement facility permitting determination of radar cross sections and location and characterization of scattering centers on aircraft models up to 4.5 m in length are described and illustrated with diagrams, drawings, graphs, and photographs. The facility comprises a 15 x 5.8 x 3.8-m measurement chamber, a rotating platform with maximum load 270 kg
THz impulse radar for biomedical sensing: nonlinear system behavior
NASA Astrophysics Data System (ADS)
Brown, E. R.; Sung, Shijun; Grundfest, W. S.; Taylor, Z. D.
The THz impulse radar is an "RF-inspired" sensor system that has performed remarkably well since its initial development nearly six years ago. It was developed for ex vivo skin-burn imaging, and has since shown great promise in the sensitive detection of hydration levels in soft tissues of several types, such as in vivo corneal and burn samples. An intriguing aspect of the impulse radar is its hybrid architecture which combines the high-peak-power of photoconductive switches with the high-responsivity and -bandwidth (RF and video) of Schottky-diode rectifiers. The result is a very sensitive sensor system in which the post-detection signal-to-noise ratio depends super-linearly on average signal power up to a point where the diode is "turned on" in the forward direction, and then behaves quasi-linearly beyond that point. This paper reports the first nonlinear systems analysis done on the impulse radar using MATLAB.
Adaptive space-time processing for interference suppression in phased array radar systems. II. Tracking radar
H. H. M. Ghouz; F. I. A. Elghany; M. M. Qutb
For pt.I see ibid., p.B8\\/1-B8\\/8 (2000). In phased array radar systems, a tracking process is performed using an electronic scan of a predetermined sector to provide a continuous information about the detected targets. In practice, the presence of interference (noise, clutter, and jamming signals) either prevent or deceive the tracking circuit to follow the real targets, and consequently, the tracking
Development of a Low-Cost UAV Doppler Radar Data System
NASA Technical Reports Server (NTRS)
Knuble, Joseph; Li, Lihua; Heymsfield, Gerry
A viewgraph presentation on the design of a low cost unmanned aerial vehicle (UAV) doppler radar data system is presented. The topics include: 1) Science and Mission Background; 2) Radar Requirements and Specs; 3) Radar Realization: RF System; 4) Processing of RF Signal; 5) Data System Design Process; 6) Can We Remove the DSP? 7) Determining Approximate Speed Requirements; 8) Radar Realization: Data System; 9) Data System Operation; and 10) Results.
Wearable System-on-a-Chip Pulse Radar Sensors for the Health Care: System Overview
Domenico Zito; Domenico Pepe; Bruno Neri; Danilo De Rossi; Antonio Lanata
A new system-on-a-chip radar sensor for next generation wearable wireless interface applied to the human health-care and safeguard is presented. The system overview is provided and a summary of the feasibility study of the radar sensor is presented. In detail, the overall system consists of a radar sensor for detecting the heart and breath rates and a low-power IEEE 802.15.4
78. View of radar systems technical publication library, transmitter building ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
78. View of radar systems technical publication library, transmitter building no. 102, second floor. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK
Improvement of Multiple Ground Targets Tracking with GMTI Sensor and Fusion of Identification Attributes
Benjamin Pannetier; Jean Dezert; E. Pollard
Multiple ground targets (MGT) tracking is a challenging problem in real environment because of partial observations, high traffic density, the maneuverability of targets, the clutter and the low target detection probabilities. Most of current MGT trackers use GMTI (Ground Moving Target Indicator) sensor, since this sensor provides the range- rate measurement (Doppler) aside classical position measurements. This helps the tracking
System aspects of a low-cost coherent radar system with AESA antenna for maritime applications
T. Bertuchi; M. Pamiesi; C. Lo?cker; P. Knott; H. Erkens; R. Wunderlich; S. Heinen
Motivated by new performance requirements and technological progress Fraunhofer FHR has initiated the development of a low-cost coherent radar system demonstrator with AESA antenna for maritime applications. The proposed system is expected to exhibit smaller operational costs and better performance than conventional shipborne navigation radar systems. In this contribution an overview of the total system was given. Emphasis was placed
Prototype fiber optic system to remote TRACALS radars
NASA Astrophysics Data System (ADS)
Radcliff, J. A.; Becker, K. E.
The transmission mediums currently used to remote Traffic Control and Landing Systems (TRACALS) radars are coaxial cables (coax) or a microwave link. Problems and limitations are encountered in using either medium. Coax is susceptible to electromagnetic interference, moisture, ground loops, lightning and electromagnetic pulse (EMP). Microwave links are susceptible to electromagnetic interference, propagation anomaly, electronic warfare and EMP. The coax remoting system used on the Precision Approach Radar (PAR) is highly susceptible to interference from power lines for runway lights and has a maximum remoting distance of 12,000 ft. Remoting TRACALS radars via a fiber optic system appeared to be a complete solution to the problems listed above. The 1842 EEG conducted a feasiblity study of the use of a FO system to remote a PAR (AFCC Technical Report, 1842 EEG/EEIT-TR-80-9). The AN/FPN-62 radar was used in conducting the study. The study demonstrated that an analog FO system can handle the combined analog/digital, time and frequency multiplexed signals which are passed over the AN/FPN-62 remoting system. A FO system appeared to be a desirable alternative and warranted a full investigation.
Methods And System Suppressing Clutter In A Gain-Block, Radar-Responsive Tag System
Ormesher, Richard C. (Albuquerque, NM); Axline, Robert M. (Albuquerque, NM)
Methods and systems reduce clutter interference in a radar-responsive tag system. A radar transmits a series of linear-frequency-modulated pulses and receives echo pulses from nearby terrain and from radar-responsive tags that may be in the imaged scene. Tags in the vicinity of the radar are activated by the radar's pulses. The tags receive and remodulate the radar pulses. Tag processing reverses the direction, in time, of the received waveform's linear frequency modulation. The tag retransmits the remodulated pulses. The radar uses a reversed-chirp de-ramp pulse to process the tag's echo. The invention applies to radar systems compatible with coherent gain-block tags. The invention provides a marked reduction in the strength of residual clutter echoes on each and every echo pulse received by the radar. SAR receiver processing effectively whitens passive-clutter signatures across the range dimension. Clutter suppression of approximately 14 dB is achievable for a typical radar system.
Scanning array radar system for bridge subsurface imaging
NASA Astrophysics Data System (ADS)
Lai, Chieh-Ping; Ren, Yu-Jiun; Yu, Tzu Yang
Early damage detection of bridge has been an important issue for modern civil engineering technique. Existing bridge inspection techniques used by State Department of Transportation (DOT) and County DOT include visual inspection, mechanical sounding, rebound hammer, cover meter, electrical potential measurements, and ultrasonics; other NDE techniques include ground penetrating radar (GPR), radiography, and some experimental types of sensors. Radar technology like GPR has been widely used for the bridge structure detection with a good penetration depth using microwave energy. The system to be presented in this paper is a different type of microwave sensing technology. It is focus on the subsurface detection and trying to find out detail information at subsurface (10 cm) with high resolution radar imaging from a flexible standoff distance. Our radar operating frequency is from 8-12 GHz, which is different from most of the current GPR systems. Scanning array antenna system is designed for adjustable beamwidth, preferable scanning area, and low sidelobe level. From the theoretical analysis and experimental results, it is found that the proposed technique can successfully capture the presence of the near-surface anomaly. This system is part of our Multi- Modal Remote Sensing System (MRSS) and provides good imaging correlations with other MRSS sensors.
Certification methodology applied to the NASA experimental radar system
NASA Technical Reports Server (NTRS)
Britt, Charles L.; Switzer, George F.; Bracalente, Emedio M.
The objective of the research is to apply selected FAA certification techniques to the NASA experimental wind shear radar system. Although there is no intent to certify the NASA system, the procedures developed may prove useful to manufacturers that plan to undergo the certification process. The certification methodology for forward-looking wind shear detection radars will require estimation of system performance in several FAA-specified microburst/clutter scenarios as well as the estimation of probabilities of missed and false hazard alerts under general operational conditions. Because of the near-impossibility of obtaining these results experimentally, analytical and simulation approaches must be used. Hazard detection algorithms were developed that derived predictive estimates of aircraft hazard from basic radar measurements of weather reflectivity and radial wind velocity. These algorithms were designed to prevent false alarms due to ground clutter while providing accurate predictions of hazard to the aircraft due to weather. A method of calculation of the probability of missed and false hazard alerts has been developed that takes into account the effect of the various algorithms used in the system and provides estimates of the probability of missed and false alerts per microburst encounter under weather conditions found at Denver, Kansas City, and Orlando. Simulation techniques have been developed that permit the proper merging of radar ground clutter data (obtained from flight tests) with simulated microburst data (obtained from microburst models) to estimate system performance using the microburst/clutter scenarios defined by the FAA.
Feasibility study of a microwave radar system for agricultural inspection
Okelo-Odongo, S.
The feasibility of an impulse radar system for agricultural inspection is investigated. This system would be able to quickly determine the quality of foodstuffs that are passed through the system. A prototype was designed at the Lawrence Livermore National Laboratory and this report discusses it`s evaluation. A variety of apples were used to test the system and preliminary data suggests that this technology holds promise for successful application on a large scale in food processing plants.
Project Report X-band Radar Wave Observation System
Newman, Michael C.
Project Report X-band Radar Wave Observation System Submitted to Minerals Management Service U. S spectrum analysis ............................................ 31 4.1.2. 2-D wave spectrum analysis ............................................. 33 4.1.3. 3-D wave spectrum analysis ............................................. 36 4.2. Given
A 94 GHz spaceborne cloud profiling radar antenna system
S. Spitz; J. Harrell; R. Perez; W. Veruttipong
The CloudSat spacecraft, scheduled to launch in 2003, will carry a 94 GHz cloud profiling radar. The electrical design of its antenna system has been completed and is presented here. It consists of a quasi-optical transmission line that performs signal relaying and duplexing (using a Faraday rotator), and a collimating antenna that provides the required gain and spatial resolution. A
Assessment of communication system susceptibility to the PAVE PAWS radar
Ernest E. Donaldson Jr.; Robert P. Burdett Jr.
This paper summarizes the results of a program directed to an assessment of the potential for interference to Georgia Power Company communications systems from the PAVE PAWS radar at Robins Air Force Base, GA. Susceptibility data were recorded on selected UHF and microwave receivers and compared to predicted PAVE PAWS field strength levels to identify potential interference problems. Several potential
Interference immunity of optical radar system with phased antenna array
Y. V. Alishev; V. Y. Yamaykin
A phased antenna array of an optical radar system with single-mode or phase-locked sources is analyzed for interference immunity. A major factor influencing the performance as well as the method of analysis is the relative magnitudes of coherence length and path difference, the latter characterizing the interference pattern of light beams and its effect on the antenna radiation pattern. Although
An automated radar-signature measurement system
NASA Astrophysics Data System (ADS)
Kruse, Juergen
The design and operation of an automated measurement facility permitting determination of radar cross sections and location and characterization of scattering centers on aircraft models up to 4.5 m in length are described and illustrated with diagrams, drawings, graphs, and photographs. The facility comprises a 15 x 5.8 x 3.8-m measurement chamber, a rotating platform with maximum load 270 kg and elevation range from -5 to +35 deg (precision 0.1 deg), a tunable broadband 2-18-GHz transmitter, a phase-sensitive receiver, and control and data-processing computers. The analytical techniques employed to correct for measurement errors and to resolve scattering centers both longitudinally and transversely (two-dimensional representation) are explained and demonstrated. The facility is currently being used to develop and evaluate stealth-type aircraft designs.
A MIMO Radar System Approach to Target Hana Godrich, Alexander M. Haimovich, and Rick S. Blum
Haimovich, Alexander
1 A MIMO Radar System Approach to Target Tracking Hana Godrich, Alexander M. Haimovich, and Rick S performnace of MIMO radar systems with distributed antennas and non-coherent processing is studied of the radars geometric layout and the target location on tracking accuracies is analyzed. The impact
Imaging method: A strong tool for moving target tracking by a multistatic UWB radar system
D. Kocur; J. Gamec; M. Svecova; M. Gamcova; J. Rovnakova
In this paper, imaging method for moving target tracking by a multistatic ultra-wideband radar system is described. The task of moving target tracking consists in estimation of a target trajectory based on processing of raw radar data obtained from all receiving channels of a radar system. Then, the imaging method applied for target tracking consists of such signal processing phases
A novel backpackable ice-penetrating radar system
Kenichi Matsuoka; Ryoji Saito; Renji Naruse
We have developed a novel ice-penetrating radar system that can be carried on a backpack. Including batteries for a 3 hour continuous measurement, the total weight is 13 kg. In addition, it operates reliably down to -25�C, has a low power consumption of 24 W, and is semi-waterproof. The system has a built-in-one controller with a high-brightness display for reading
Assessment of communication system susceptibility to the PAVE PAWS radar
NASA Astrophysics Data System (ADS)
Donaldson, Ernest E., Jr.; Burdett, Robert P., Jr.
This paper summarizes the results of a program directed to an assessment of the potential for interference to Georgia Power Company communications systems from the PAVE PAWS radar at Robins Air Force Base, GA. Susceptibility data were recorded on selected UHF and microwave receivers and compared to predicted PAVE PAWS field strength levels to identify potential interference problems. Several potential problems were identified which must be addressed to preclude PAVE PAWS related interference effects on communication system performance.
Radio Aurora Explorer: Mission science and radar system
NASA Astrophysics Data System (ADS)
Bahcivan, H.; Cutler, J. W.
The Radio Aurora Explorer (RAX) satellite is the first of several satellites funded under the NSF CubeSat-based Space Weather and Atmospheric Research Program. RAX is a ground-to-space bi-static radar remote sensing experiment designed to measure and understand the causes of meter-scale ionospheric irregularities. Also known as field-aligned irregularities (FAI), such non-thermal, coherent fluctuations of electron density occur in response to strong ionospheric flows or plasma density gradients during geomagnetic disturbances and are considered a space weather concern due to disruption to communication and navigation signals. The RAX CubeSat was launched in November 2010 and conducted a single experiment in coordination with the Poker Flat Incoherent Scatter Radar. Due to geophysical inactivity, e.g., lack of strong ionospheric electric fields and low ionospheric densities, no FAI were expected or observed. However, the radar receiver payload operation was successfully demonstrated, including the capability to sense signals as low as -110 dBm, the capability of transmitter-receiver synchronization and accurate ranging, processing of 1.2 GB of raw radar data on board in less than 1 hour, and the downlink of the science results within three-four passes. Analysis of the payload data shows that the noise level is sufficiently low. Although the interference level is a concern, it does not appear to significantly limit the measurements. Toward the end of December 2010, the solar power system gradually degraded and the mission terminated in early February 2011 after prolonged loss of contact with the satellite. Meanwhile, RAX II was launched in October 2011 to a polar orbit. This paper describes the RAX science and radar system and presents the results from the first experiment conducted.
Sub-array level simulation of an active electronically scanned array radar for integrated system design
N. W. Ramsey; C. McComb; D. W. Greig
An overview of a complete simulation of an active electronically scanned array (AESA) radar system is given. The Airborne Radar Environment Simulation (ARES) tool has been developed to represent signals emanating from the radar's environment at the sub-array level. This data forms the input to a test bed simulation in which signal processing algorithms can be developed, in particular adaptive
Ku band - The first year of operation. [Shuttle Orbiter integrated communication and radar system
NASA Technical Reports Server (NTRS)
Griffin, J. W.; Haddad, H.; Magnusson, H. G.; Mohler, C. L.
The Space Shuttle Orbiter's Ku-band integrated radar and communications system furnishes the preferred link through the Tracking and Data Relay Satellite (TRDS), providing rendezvous radar function. During the first year of operations, communications through TRDS provided a channel for the 48 Mbps data from Spacelab. Attention is presently given to the most significant activities of the radar during its initial year.
Low power FMCW radar system for level gaging
D. Brumbi
A novel low-power microwave sensor for level gaging in storage tanks has been developed. By using a PLL-controlled gated oscillator this FMCW radar can be operated in a standard 4-20 mA loop without additional supply power. The chosen system design features a fast settling time of the oscillators to achieve a quasi-continuous frequency sweep, resulting in a precise, stable and
Target localization accuracy gain in MIMO radar-based systems
Hana Godrich; Alexander M. Haimovich; Rick S. Blum
This paper presents an analysis of target localization accuracy, attainable by the use of multiple-input multiple-output (MIMO) radar systems, configured with multiple transmit and receive sensors, widely distributed over an area. The Cramer-Rao lower bound (CRLB) for target localization accuracy is developed for both coherent and noncoherent processing. Coherent processing requires a common phase reference for all transmit and receive
Modelling and simulation of a stepped frequency radar system based on LabVIEW
Huan Liu; Yong-feng Zhu; Jun He; Hong-zhong Zhao; Qiang Fu
In the radar system, modelling and simulation can guarantee the high reliability and correctness of system design, shorten designing period and reduce development cost. This paper discusses signal processing system of the SFR (stepped-frequency radar), especially the several key processing steps to get the HRRP (high resolution rang profile). The system simulation has done based on LabVIEW (Laboratory Virtual Instrument
Design and realization of a multimission-capable 70 GHz FM/CW radar reception system
NASA Astrophysics Data System (ADS)
Kreutzer, E.
A radar which can present three-dimensional scenes on a two-dimensional screen at intervals of a few hundredths of a second is described. Signal and system theory for FM/CW radars is first reviewed, and the system design for the FM/CW radar under consideration is presented. A comparative signal analysis of two radar reception systems is given, and the effect of nonideal FM/CW signals on the orientation spectrum is considered. Finally, the realization and technical measurement testing of the system are addressed.
A Foliage Penetration Imaging Radar System
Massachusetts at Lowell, University of
#12;-30 -20 -10 0 10 20 -34 -32 -30 -28 -26 -24 -22 -20 -18 -16 -14 -12 -10 Plate Area 'A' (dBsm) RCS(dBsm) 8.2 GHz Data 8.2 GHz Predicted RCS 12.4 GHz Data 12.4 GHz Predicted RCS System Linearity !! " # $$ % & = 2 2 10 4 log10 ' ( ) A dBsm�Predicted RCS �Spot size at upper-band limits maximum dimensions
Integrated radar-camera security system: experimental results
NASA Astrophysics Data System (ADS)
Zyczkowski, M.; Palka, N.; Trzcinski, T.; Dulski, R.; Kastek, M.; Trzaskawka, P.
The nature of the recent military conflicts and terrorist attacks along with the necessity to protect bases, convoys and patrols have made a serious impact on the development of more effective security systems. Current widely-used perimeter protection systems with zone sensors will soon be replaced with multi-sensor systems. Multi-sensor systems can utilize day/night cameras, IR uncooled thermal cameras, and millimeter-wave radars which detect radiation reflected from targets. Ranges of detection, recognition and identification for all targets depend on the parameters of the sensors used and of the observed scene itself. In this paper two essential issues connected with multispectral systems are described. We will focus on describing the autonomous method of the system regarding object detection, tracking, identification, localization and alarm notifications. We will also present the possibility of configuring the system as a stationary, mobile or portable device as in our experimental results.
Solid-state coherent laser radar wind field measurement systems
NASA Astrophysics Data System (ADS)
Milton Huffaker, R.; Reveley, Paul A.
Diode-pumped solid-state pulsed coherent laser radar systems have recently been developed at Coherent Technologies, Inc., for the remote measurement of atmospheric wind fields. Flashlamp-pumped systems have been utilized since 1990 for obtaining wind field measurements. These flashlamp-pumped lidar systems have been applied to wind profiling, aircraft-wake vortex measurements, airport wind shear and gust front monitoring, military cargo air drops and many other applications. The diode-pumped coherent lidar systems currently available are capable of near turnkey operation. The Tm:YAG laser transceivers operate at 0963-9659/7/4/021/img1 with output pulse energies of 1-10 mJ with PRFs of 1000 to 100 Hz, respectively. Range resolutions of 30-75 m are typical. A real-time lidar signal processor has also been developed for collecting and analysing laser radar (lidar) data. The signal processor is based on a commercial PC architecture and offers a real-time data acquisition, analysis, display, recording and playback environment. Wind measurements and overall system performance results will be presented. Wind measurement performance, for a variety of applications, is presented using the flashlamp- and diode-pumped coherent lidars including measured wind profiles from ground and on aircraft, wake vortex tracking results, and example flows over mountain terrain.
A FMCW Radar Acquisition and Process System Based on LabVIEW
Zhang Da-Biao; Zhao Zeng-rong; Bai Ran
This paper presents a acquisition and process system for frequency modulation continuous wave (FMCW) radar. The procedure is designed by LabVIEW7.0. The system adopts FMCW radar sensor and high-quality data acquisition card. The intermediate frequency (IF) signal of the FMCW radar can be collected in time. The intermediate frequency, distance and velocity forward vehicle can be calculated by an improved
Quasi-Orthogonal Wideband Radar Waveforms Based on Chaotic Systems
Willsey, Matt S.
Many radar applications, such as those involving multiple-input, multiple-output (MIMO) radar, require sets of waveforms that are orthogonal, or nearly orthogonal. As shown in the work presented here, a set of nearly ...
The Goldstone solar system radar: A science instrument for planetary research
NASA Technical Reports Server (NTRS)
Dvorsky, J. D.; Renzetti, N. A.; Fulton, D. E.
The Goldstone Solar System Radar (GSSR) station at NASA's Deep Space Communications Complex in California's Mojave Desert is described. A short chronological account of the GSSR's technical development and scientific discoveries is given. This is followed by a basic discussion of how information is derived from the radar echo and how the raw information can be used to increase understanding of the solar system. A moderately detailed description of the radar system is given, and the engineering performance of the radar is discussed. The operating characteristics of the Arcibo Observatory in Puerto Rico are briefly described and compared with those of the GSSR. Planned and in-process improvements to the existing radar, as well as the performance of a hypothetical 128-m diameter antenna radar station, are described. A comprehensive bibliography of referred scientific and engineering articles presenting results that depended on data gathered by the instrument is provided.
Fade: a vehicle detection and tracking system featuring monocular color vision and radar data fusion
B. Steux; C. Laurgeau; L. Salesse; D. Wautier
This paper presents Fade, a vehicle detection and tracking system featuring monocular color vision and radar data fusion. Its main originality resides in its low-level fusion system. At each step and for each target, the fusion system fuses the results of four different image processing algorithms and radar information by automatically combining 12 different features and generating many possible target
A Portable Low-Power Harmonic Radar System and Conformal Tag for Insect Tracking
Technology Transfer Automated Retrieval System (TEKTRAN)
Harmonic radar systems provide an effective modality for tracking insect behavior. This paper presents a harmonic radar system proposed to track the migration of the Emerald Ash Borer (EAB). The system offers a unique combination of portability, low power and small tag design. It is comprised of a...
Generalized radar/radiometry imaging problems
Gen�ve, Universit� de
Paper Generalized radar/radiometry imaging problems Ivan Prudyus, Sviatoslav Voloshynovskiy, Andriy- ing simulation based on radar, synthetic aperture radar (SAR) and radiometry systems are presented systems, synthetic aperture radar, spatio-temporal imaging. 1. Introduction Resolution of radar
Fiber optic coherent laser radar 3D vision system
Clark, R.B.; Gallman, P.G.; Slotwinski, A.R. [Coleman Research Corp., Springfield, VA (United States); Wagner, K.; Weaver, S.; Xu, Jieping [Colorado Univ., Boulder, CO (United States)
This CLVS will provide a substantial advance in high speed computer vision performance to support robotic Environmental Management (EM) operations. This 3D system employs a compact fiber optic based scanner and operator at a 128 x 128 pixel frame at one frame per second with a range resolution of 1 mm over its 1.5 meter working range. Using acousto-optic deflectors, the scanner is completely randomly addressable. This can provide live 3D monitoring for situations where it is necessary to update once per second. This can be used for decontamination and decommissioning operations in which robotic systems are altering the scene such as in waste removal, surface scarafacing, or equipment disassembly and removal. The fiber- optic coherent laser radar based system is immune to variations in lighting, color, or surface shading, which have plagued the reliability of existing 3D vision systems, while providing substantially superior range resolution.
Robust radar detection of GMTI targets with STAP D. M. Carrington and Dr. P. G. Kealey
Haddadi, Hamed
processing can be performed either before Fast Fourier Transform (FFT) (pre-Doppler) or after FFT (post, but it is described in detail by Klemm [3]. In summary, STAP attempts to minimise the received power subject to the filters formed either side of the target (dashed lines in Figure 1). This failure is caused
On-board fault-tolerant SAR processor for spaceborne imaging radar systems
NASA Technical Reports Server (NTRS)
Fang, Wai-Chi; Le, Charles; Taft, Stephanie
A real-time high-performance and fault-tolerant FPGA-based hardware architecture for the processing of synthetic aperture radar (SAR) images has been developed for advanced spaceborne radar imaging systems. In this paper, we present the integrated design approach, from top-level algorithm specifications, system architectures, design methodology, functional verification, performance validation, down to hardware design and implementation.
Multistatic ambiguity function - A tool for waveform selection in distributed radar systems
Ivan Bradaric; Gerard T. Capraro; Michael C. Wicks
The multistatic ambiguity function has been proposed as a tool for analyzing and designing multistatic radar systems. It was demonstrated through previous examples that multistatic radar system performances (e.g. probability of detection, range and velocity resolution) can be improved by shaping the multistatic ambiguity function through waveform selection, sensor positioning and adequate weighting of different receivers. In this work we
A Framework for the Analysis of Multistatic Radar Systems with Multiple Transmitters
I. Bradaric; G. T. Capraro; D. D. Weiner; M. C. Wicks
The multistatic ambiguity function can be used as a tool for analyzing multistatic radar systems. It has been demonstrated that the multistatic ambiguity function can serve as a guideline for developing multistatic radar signal processing rules and waveform selection strategies in system configurations with a single transmitter and multiple receivers. In this work we extend the development of multistatic ambiguity
Multiple-scattering in radar systems: A review Alessandro Battaglia a,b,, Simone Tanelli c
Hogan, Robin
), which may eventually drive the signal below the minimum detection threshold. In such circumstancesCARE 94 GHz, and the GPM dual 13�35 GHz radars. These systems are able to detect the vertical distributionReview Multiple-scattering in radar systems: A review Alessandro Battaglia a,b,�, Simone Tanelli c
Real-data tests of a single-Doppler radar assimilation system
Thomas Nehrkorn; James Hegarty; Thomas M. Hamill
Real data tests of a single-Doppler radar data assimilation and forecast system have been conducted for a Florida sea breeze case. The system consists of a hydrostatic mesoscale model used for prediction of the preconvective boundary layer, an objective analysis that combines model first guess fields with radar derived horizontal winds, a thermodynamic retrieval scheme that obtains temperature information from
Goldstone Solar System Radar Observatory: Earth-Based Planetary Mission Support and Unique Science Results
Martin A. Slade; Lance A. M. Benner; Arnold Silva
The Goldstone Solar System Radar (GSSR) facility is the only fully steerable radar in the world for high-resolution ranging and imaging of planetary and small-body targets. These observations provide information on surface characteristics, orbits, rotations, and polar ices for a wide variety of solar system objects. The resulting data are used not just for scientific studies of these objects, but
A novel backpackable ice-penetrating radar system
NASA Astrophysics Data System (ADS)
Matsuoka, Kenichi; Saito, Ryoji; Naruse, Renji
We have developed a novel ice-penetrating radar system that can be carried on a backpack. Including batteries for a 3 hour continuous measurement, the total weight is 13 kg. In addition, it operates reliably down to -25�C, has a low power consumption of 24 W, and is semi-waterproof. The system has a built-in-one controller with a high-brightness display for reading data quickly, a receiver with 12-bit digitizing, and a 1 kV pulse transmitter in which the pulse amplitude varies by <0.2%. Optical communications between components provides low-noise data acquisition and allows synchronizing of the pulse transmission with sampling. Measurements with the system revealed the 300 m deep bed topography of a temperate valley glacier in the late ablation season.
Limitations of Radar Coordinates
Donato Bini; Luca Lusanna; Bahram Mashhoon
The construction of a radar coordinate system about the world line of an observer is discussed. Radar coordinates for a hyperbolic observer as well as a uniformly rotating observer are described in detail. The utility of the notion of radar distance and the admissibility of radar coordinates are investigated. Our results provide a critical assessment of the physical significance of radar coordinates.
Performance analysis of pulse Doppler digital radars with application to the Shuttle Ku-band system
NASA Technical Reports Server (NTRS)
Alem, W. K.; Weber, C. L.
A pulse Doppler digital radar is one of the primary components of the Ku-band integrated radar and communication equipment on the Space Shuttle. The performance of the Ku-band rendezvous radar to be used on the Space Shuttle is analyzed in four parts. First an overall functional block diagram description is presented to illustrate the signal processing in the detection and the tracking modes. The detection capabilities and limitations of the radar are investigated taking all of the system losses into account. A new unified analysis of digital radar tracking loops is developed which takes into consideration the effects of a scintillating target and receiver front end noise. The behavior of the radar is discussed in the presence of thermal noise, amplitude scintillation, and target glint.
Auxiliary signal processing system for a multiparameter radar
NASA Technical Reports Server (NTRS)
Chandrasekar, V.; Gray, G. R.; Caylor, I. J.
The design of an auxiliary signal processor for a multiparameter radar is described with emphasis on low cost, quick development, and minimum disruption of radar operations. The processor is based around a low-cost digital signal processor card and personal computer controller. With the use of such a concept, an auxiliary processor was implemented for the NCAR CP-2 radar during a 1991 summer field campaign and allowed measurement of additional polarimetric parameters, namely, the differential phase and the copolar cross correlation. Sample data are presented from both the auxiliary and existing radar signal processors.
HF radar in French Mediterranean Sea: an element of MOOSE Mediterranean Ocean Observing System on Environment
Boyer, Edmond
HF radar in French Mediterranean Sea: an element of MOOSE Mediterranean Ocean Observing System for the MOOSE program. 2 HF RADAR DEPLOYMENT IN NORTH WESTERN MEDITERRANEAN SEA The chosen sites for this HF , Pascal Guterman2 , Karim Bernardet2 1 Mediterranean Institute of Oceanography (MIO, UM 110, USTV
Matched-Illumination Waveform Design for a Multistatic Through-the-Wall Radar System
Fauzia Ahmad; Moeness G. Amin
We present the matched illumination waveform design for improved target detection in through-the-wall radar imaging and sensing applications. We consider a multistatic radar system for detection of stationary targets with known impulse responses behind walls. The stationary and slowly moving nature of typical indoor targets relaxes the orthogonality requirement on the waveforms, thereby allowing sequential transmissions from each transmitter with
Concept of multistatic Passive radar based on wireless packet communication systems
Krzysztof Kulpa; Stanislaw Rzewuski; Zbigniew Gajo; Mateusz Malanowski
In this paper a concept of passive radar system based on packet wireless network illuminators is presented. The network consists of several transmitters\\/receivers using the same bandwidth, exchanging data packets. The passive radar listens to the communication, and decoding packets determines the source transmitter. The time windows are used to select transmission form single source and window signal is processed
Height Target Estimation in a Three Positioned Radar System Christo Kabakchiev, Ivan Garvanov, Vladimir Kyovtorov
Borissova, Daniela
108 Height Target Estimation in a Three Positioned Radar System Christo Kabakchiev, Ivan Garvanov, Vladimir Kyovtorov Institute of Information Technologies, 1113 Sofia Abstract: The target height error of the three-positioned radar in order to increase the measurement accuracy. Keywords: height target estimation
The Design of a High Performance MMW Radar System for Autonomous Land Vehicle Navigation
S. Clark; H. Durrant Whyte
This paper describes the design of a high performance 77GHz millimetre wave radar, signal processing and control system for use in autonomous vehicle navigation. The radar front end and intermediate frequency components are described together with a method of distinguishing pre-placed target beacons from other reflectors using the polarisation of the reflected signal. Digital signal processing hardware is described which
A Digital Array Radar with a Hierarchical System Architecture Caleb Fulton, Patrick Clough, Vijay Pai, and William Chappell
A Digital Array Radar with a Hierarchical System Architecture Caleb Fulton, Patrick Clough, Vijay -- A digital array radar system prototype is pre sented that makes use of a hierarchical digital backend for future radars that fully embrace the concept of lowcost inte gration in a panelized platform
High Resolution Radar Detection of Individual Raindrops in Natural Cloud Systems
NASA Astrophysics Data System (ADS)
Schmidt, J.; Flatau, P. J.; Harasti, P. R.; Yates, R. D.
A high resolution C-band Doppler radar previously used to detect debris shed during space shuttle missions is shown to have the capability to determine the properties of individual raindrops in the free atmosphere. This is accomplished through a combination of the radar's narrow (0.22 degree) beamwidth, a range resolution as fine as 0.5m, and extremely high 3MW power. These attributes lead to exceptionally small radar pulse volumes (as low as 14m3 at the radar's minimum 2km range) and allow the radar to detect individual drops that exceed 0.5mm in diameter. As the radar transmits both a higher (0.5m) and lower (37m) range resolution waveform every other pulse, a unique opportunity arise to examine both the bulk radar reflectivity and individual particle properties at the same time. The larger individual drops detected by the radar appear in the radar data as bright, nearly linear, reflectivity "streaks" against the more uniform background reflectivity field generated by the population of smaller drops. These streaks can then be examined to infer the properties of the particles directly such as their size, fall velocity, concentration, and potentially other properties such as naturally occurring drop oscillations. Examples of the bulk and individual particle properties for several "streaks" associated with a deep convective system are examined. Additional high-resolution studies of the circulation fields associated with a shallow altocumulus layer and a long-lived radar reflectivity bright band associated with the melting layer within a meso-convective cloud system reveal new details of the internal circulation features associated with these phenomena.
Estimation of Microphysical and Radiative Parameters of Precipitating Cloud Systems Using mm-Wavelength Radars
NASA Astrophysics Data System (ADS)
Matrosov, Sergey Y.
A remote sensing approach is described to retrieve cloud and rainfall parameters within the same precipitating system. This approach is based on mm-wavelength radar signal attenuation effects which are observed in a layer of liquid precipitation containing clouds and rainfall. The parameters of ice clouds in the upper part of startiform precipitating systems are then retrieved using the absolute measurements of radar reflectivity. In case of the ground-based radar location, these measurements are corrected for attenuation in the intervening layer of liquid hydrometers.
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
7. CLOSE-UP FRONT VIEW OF RADAR SYSTEM EMITTER/ANTENNA (TYPICAL DEVICE PHOTOGRAPH). - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA
Quasi-orthogonal wideband radar waveforms based on chaotic systems
Willsey, Matt (Matt S.)
With the development of A/D converters possessing sufficiently high sampling rates, it is now feasible to use arbitrary, wideband waveforms in radar applications. Large sets of quasi-orthogonal, wideband waveforms can be ...
Earth resources shuttle imaging radar. [systems analysis and design analysis of pulse radar for earth resources information system
NASA Technical Reports Server (NTRS)
A report is presented on a preliminary design of a Synthetic Array Radar (SAR) intended for experimental use with the space shuttle program. The radar is called Earth Resources Shuttle Imaging Radar (ERSIR). Its primary purpose is to determine the usefulness of SAR in monitoring and managing earth resources. The design of the ERSIR, along with tradeoffs made during its evolution is discussed. The ERSIR consists of a flight sensor for collecting the raw radar data and a ground sensor used both for reducing these radar data to images and for extracting earth resources information from the data. The flight sensor consists of two high powered coherent, pulse radars, one that operates at L and the other at X-band. Radar data, recorded on tape can be either transmitted via a digital data link to a ground terminal or the tape can be delivered to the ground station after the shuttle lands. A description of data processing equipment and display devices is given.
System concept for the next-generation spaceborne precipitation radars
E. Im; S. L. Durden; G. Sadowy; A. Berkun; J. Huang; M. Lou; B. C. Lopez; Y. Rahmat-Samii; S. Rengarajan
The 13.8-GHz Precipitation Radar (PR) aboard the US\\/Japan Tropical Rainfall Measuring Mission (TRMM) satellite is the first rain profiling radar ever launched into space. A TRMM follow-on mission, called the Global Precipitation Mission (GPM), is currently planned to extend and to improve the TRMM acquired rainfall data set. One of the key components of the GPM science instrumentation is an
Moving Target Indication for Multichannel Airborne Radar Systems
L. Lidicky
Moving target indication (MTI) using radar is of great interest in civil and military applications. Its uses include airborne or space-borne surveillance of ground moving vehicles (cars, trains) or ships at sea, for instance. Airborne (space-borne) radar offers several advantages when compared to optical imaging, they include: day-andnight, all-weather capability and a possibly greater potential in resolving moving objects in
Multistatic ambiguity function � A tool for waveform selection in distributed radar systems
I. Bradaric; G. T. Capraro; M. C. Wicks
Summary form only given. The desire to anticipate, find, fix, track, target, engage, and assess, anything, anytime, anywhere (A2F2TE4A) by the US Air Force will require changes to how we modify, build, and deploy monostatic and multistatic radar systems. The multistatic ambiguity function has been proposed as a tool for analyzing and designing multistatic radar systems. It was demonstrated through
Radar, satellite, and lightning characteristics of select mesoscale convective systems in Texas�
Toracinta, Ernest Richard
RADAR, SATELLITE, AND LIGHTNING CHARACTERISTICS OF SELECT MESOSCALE CONVECTIVE SYSTEMS IN TEXAS A Thesis by ERNEST RICHARD TORACINTA Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE December 1995 Major Subject: Meteorology RADAR, SATELLITE, AND LIGHTNING CHARACTERISTICS OF SELECT MESOSCALE CONVECTIVE SYSTEMS IN TEXAS A Thesis by ERNEST RICHARD TORACINTA Submitted to Texas A...
Sea Clutter Reduction and Target Enhancement by Neural Networks in a Marine Radar System
Vicen-Bueno, Ra�l; Carrasco-�lvarez, Rub�n; Rosa-Zurera, Manuel; Nieto-Borge, Jos� Carlos
The presence of sea clutter in marine radar signals is sometimes not desired. So, efficient radar signal processing techniques are needed to reduce it. In this way, nonlinear signal processing techniques based on neural networks (NNs) are used in the proposed clutter reduction system. The developed experiments show promising results characterized by different subjective (visual analysis of the processed radar images) and objective (clutter reduction, target enhancement and signal-to-clutter ratio improvement) criteria. Moreover, a deep study of the NN structure is done, where the low computational cost and the high processing speed of the proposed NN structure are emphasized. PMID:22573993
E. Malowicki
A method is presented for the determination of radar frequency radiation power densities that the PAVE PAWS radar system could produce in its air and ground environment. The effort was prompted by the concern of the people in the vicinity of OTIS AFB MA and BEALE AFB CA about the possible radar frequency radiation hazard of the PAVE PAWS radar.
Robert Meneghini; Toshiaki Kozu
The present work on the development status of spaceborne weather radar systems and services discusses radar instrument complementarities, the current forms of equations for the characterization of such aspects of weather radar performance as surface and mirror-image returns, polarimetry, and Doppler considerations, and such essential factors in spaceborne weather radar design as frequency selection, scanning modes, and the application of
NASA Technical Reports Server (NTRS)
Moore, R. K.; Eckerman, J.; Meneghini, R.; Atlas, D.; Boerner, W. M.; Cherry, S.; Clark, J. F.; Doviak, R. J.; Goldhirsh, J.; Lhermitte, R. M.
The spaceborne radar panel considered how radar could be used to measure precipitation from satellites. The emphasis was on how radar could be used with radiometry (at microwave, visible (VIS), and infrared (IR) wavelengths) to reduce the uncertainties of measuring precipitation with radiometry alone. In addition, the fundamental electromagnetic interactions involved in the measurements were discussed to determine the key work areas for research and development to produce effective instruments. Various approaches to implementing radar systems on satellites were considered for both shared and dedicated instruments. Finally, a research and development strategy was proposed for establishing the parametric relations and retrieval algorithms required for extracting precipitation information from the radar and associated radiometric data.
Dual-Frequency Airborne Scanning Rain Radar Antenna System
NASA Technical Reports Server (NTRS)
Hussein, Ziad A.; Green, Ken
A compact, dual-frequency, dual-polarization, wide-angle-scanning antenna system has been developed as part of an airborne instrument for measuring rainfall. This system is an upgraded version of a prior single-frequency airborne rain radar antenna system and was designed to satisfy stringent requirements. One particularly stringent combination of requirements is to generate two dual-polarization (horizontal and vertical polarizations) beams at both frequencies (13.405 and 35.605 GHz) in such a way that the beams radiated from the antenna point in the same direction, have 3-dB angular widths that match within 25 percent, and have low sidelobe levels over a wide scan angle at each polarization-and-frequency combination. In addition, the system is required to exhibit low voltage standing-wave ratios at both frequencies. The system (see figure) includes a flat elliptical scanning reflector and a stationary offset paraboloidal reflector illuminated by a common-aperture feed system that comprises a corrugated horn with four input ports one port for each of the four frequency-and-polarization combinations. The feed horn is designed to simultaneously (1) under-illuminate the reflectors 35.605 GHz and (2) illuminate the reflectors with a 15-dB edge taper at 13.405 GHz. The scanning mirror is rotated in azimuth to scan the antenna beam over an angular range of 20 in the cross-track direction for wide swath coverage, and in elevation to compensate for the motion of the aircraft. The design of common-aperture feed horn makes it possible to obtain the required absolute gain and low side-lobe levels in wide-angle beam scanning. The combination of the common-aperture feed horn with the small (0.3) focal-length-to-diameter ratio of the paraboloidal reflector makes it possible for the overall system to be compact enough that it can be mounted on a DC-8 airplane.
Current status of airborne active phased array (AESA) radar systems and future trends
Hans Hommel; Heinz-Peter Feldle
AESA technology reached a mature technology level and is being adopted by advanced radar programmes. TiR modules are the key enabling technology and cost reduction efforts in this field are io progress. For future applications GaN, MEMS RF Switches and tile type T\\/R modules are anticipated and will pave the way for conformal and multi-function AESA radar systems.
Current status of airborne active phased array (AESA) radar systems and future trends
Hans Hommel; Heinz-Peter Feldle
AESA technology reached a mature technology level and is being adopted by advanced radar programmes. T\\/R modules are the key enabling technology and cost reduction efforts in this field are in progress. For future applications, GaN, MEMS RF switches and tile type T\\/R modules are anticipated and will pave the way for conformal and multi-function AESA radar systems.
Standoff concealed weapon detection using a 350 GHz radar imaging system
Sheen, David M.; Hall, Thomas E.; Severtsen, Ronald H.; McMakin, Douglas L.; Hatchell, Brian K.; Valdez, Patrick LJ
The Pacific Northwest National Laboratory is currently developing a 350 GHz, active, wideband, three-dimensional, radar imaging system to evaluate the feasibility of active sub-mm imaging for standoff concealed weapon detection. The prototype radar imaging system is based on a wideband, heterodyne, frequency-multiplier-based transceiver system coupled to a quasi-optical focusing system and high-speed rotating conical scanner. The wideband operation of this system provides accurate ranging information, and the images obtained are fully three-dimensional. Recent improvements to the system include increased imaging speed using improved balancing techniques, wider bandwidth, and image display techniques.
New Cloud Science from the New ARM Cloud Radar Systems (Invited)
NASA Astrophysics Data System (ADS)
Wiscombe, W. J.
The DOE ARM Program is deploying over $30M worth of scanning polarimetric Doppler radars at its four fixed and two mobile sites, with the object of advancing cloud lifecycle science, and cloud-aerosol-precipitation interaction science, by a quantum leap. As of 2011, there will be 13 scanning radar systems to complement its existing array of profiling cloud radars: C-band for precipitation, X-band for drizzle and precipitation, and two-frequency radars for cloud droplets and drizzle. This will make ARM the world�s largest science user of, and largest provider of data from, ground-based cloud radars. The philosophy behind this leap is actually quite simple, to wit: dimensionality really does matter. Just as 2D turbulence is fundamentally different from 3D turbulence, so observing clouds only at zenith provides a dimensionally starved, and sometimes misleading, picture of real clouds. In particular, the zenith view can say little or nothing about cloud lifecycle and the second indirect effect, nor about aerosol-precipitation interactions. It is not even particularly good at retrieving the cloud fraction (no matter how that slippery quantity is defined). This talk will review the history that led to this development and then discuss the aspirations for how this will propel cloud-aerosol-precipitation science forward. The step by step plan for translating raw radar data into information that is useful to cloud and aerosol scientists and climate modelers will be laid out, with examples from ARM�s recent scanning cloud radar deployments in the Azores and Oklahoma . In the end, the new systems should allow cloud systems to be understood as 4D coherent entities rather than dimensionally crippled 2D or 3D entities such as observed by satellites and zenith-pointing radars.
New methods to identification and classification of the targets in the car radar imaging systems
I. V. Minin; O. V. Minin
Imaging systems (with the quality of the radio images �equal� to optical images of the targets) using �isotropic radiovision� are suggested. The most important fields of applications of this method are: imaging radar, security systems, custom control systems, AVC and AVI systems
Department of Electrical Engineering Fall 2011 Automatic Motion Compensated Radar Target Mounting System
Demirel, Melik C.
PENNSTATE Department of Electrical Engineering Fall 2011 Automatic Motion Compensated Radar Target to build the gimbal system A system was designed which the customer will use CAD models and electrical schematics were given to the customer for future systems Testing was performed to test the gimbal system
Low Cost Open Architecture Radar Systems University College London
Haddadi, Hamed
surveillance) Antenna gain ( rt GG , ) = 300 (typical for ideal 1m2 area dish at nominal 1.5GHz RF) Radar cross section ( ) = 1m2 (for a person or small vehicle) RF wavelength ( ) = 0.2m (for nominal 1.5GHz RF) Total peak transmission power from the (1) #12;amplifier, and doppler processing may necessitate a higher
Ultrawideband radar echoes of land mine targets measured at oblique incidence using a 250-kW impulse radar system
NASA Astrophysics Data System (ADS)
Chant, Ian J.; Staines, Geoff
United Nations Peacekeeping forces around the world need to transport food, personnel and medical supplies through disputed regions were land mines are in active use as road blocks and terror weapons. A method of fast, effective land mine detection is needed to combat this threat to road transport. The technique must operate from a vehicle travelling at a reasonable velocity and give warning far enough ahead for the vehicle to stop in time to avoid the land mine. There is particular interest in detecting low- metallic content land mines. One possible solutionis the use of ultra-wide-band (UWB) radar. The Australian Defence Department is investigating the feasibility of using UWB radar for land mine detection from a vehicle. A 3 GHz UWB system has been used to collect target response from a series of inert land mines and mine-like objects placed on the ground and buried in the ground. The targets measured were a subset of those in the target set described in Wong et al. with the addition of inert land mines corresponding to some of the surrogate targets in this set. The results are encouraging for the detection of metallic land mines and the larger non-metallic land mines. Smaller low-metallic- content anti-personnel land mines are less likely to be detected.
Space shuttle Ku-band integrated rendezvous radar/communications system study
NASA Technical Reports Server (NTRS)
The results are presented of work performed on the Space Shuttle Ku-Band Integrated Rendezvous Radar/Communications System Study. The recommendations and conclusions are included as well as the details explaining the results. The requirements upon which the study was based are presented along with the predicted performance of the recommended system configuration. In addition, shuttle orbiter vehicle constraints (e.g., size, weight, power, stowage space) are discussed. The tradeoffs considered and the operation of the recommended configuration are described for an optimized, integrated Ku-band radar/communications system. Basic system tradeoffs, communication design, radar design, antenna tradeoffs, antenna gimbal and drive design, antenna servo design, and deployed assembly packaging design are discussed. The communications and radar performance analyses necessary to support the system design effort are presented. Detailed derivations of the communications thermal noise error, the radar range, range rate, and angle tracking errors, and the communications transmitter distortion parameter effect on crosstalk between the unbalanced quadriphase signals are included.
Future Trends in Automotive Radar \\/ Imaging Radar
J. Wenger
There is a growing interest of car manufacturers in sensors monitoring the car's surrounding area in order to improve safety systems from mere crash survival to crash prediction or prevention by early detection of hazardous situations. Therefore radar sensors have been intensively investigated for many years. A large variety of radar based vehicular sensors have been developed. Narrow-beam radars are
Comparing Goldstone Solar System Radar Earth-based Observations of Mars with Orbital Datasets
NASA Technical Reports Server (NTRS)
Haldemann, A. F. C.; Larsen, K. W.; Jurgens, R. F.; Slade, M. A.
The Goldstone Solar System Radar (GSSR) has collected a self-consistent set of delay-Doppler near-nadir radar echo data from Mars since 1988. Prior to the Mars Global Surveyor (MGS) Mars Orbiter Laser Altimeter (MOLA) global topography for Mars, these radar data provided local elevation information, along with radar scattering information with global coverage. Two kinds of GSSR Mars delay-Doppler data exist: low 5 km x 150 km resolution and, more recently, high (5 to 10 km) spatial resolution. Radar data, and non-imaging delay-Doppler data in particular, requires significant data processing to extract elevation, reflectivity and roughness of the reflecting surface. Interpretation of these parameters, while limited by the complexities of electromagnetic scattering, provide information directly relevant to geophysical and geomorphic analyses of Mars. In this presentation we want to demonstrate how to compare GSSR delay-Doppler data to other Mars datasets, including some idiosyncracies of the radar data. Additional information is included in the original extended abstract.
The Influence of Random Phase Errors on the Angular Resolution of Synthetic Aperture Radar Systems
Jean A. Develet
The influence of random phase errors on the angular resolution of a focused synthetic aperture radar system is treated. The principal measure of performance has been taken as the mean envelope power at the system output. This system output power is evaluated exactly, although not in closed form, based on the following assumptions: 1) the real beam pattern is Gaussian;
MIMO radar, SIMO radar, and IFIR radar: a P. P. Vaidyanathan and Piya Pal
Vaidyanathan, P. P.
MIMO radar, SIMO radar, and IFIR radar: a comparison P. P. Vaidyanathan and Piya Pal Dept and SIMO radar systems for the case where the transmitter and receiver are collocated. The simplicity of the application allows one to see clearly where the advantages of MIMO radar come from, and what the tradeoffs are
Radar observations of the 2009 eruption of Redoubt Volcano, Alaska: Initial deployment of a transportable Doppler radar system for volcano-monitoring
NASA Astrophysics Data System (ADS)
Hoblitt, R. P.; Schneider, D. J.
The rapid detection of explosive volcanic eruptions and accurate determination of eruption-column altitude and ash-cloud movement are critical factors in the mitigation of volcanic risks to aviation and in the forecasting of ash fall on nearby communities. The U.S. Geological Survey (USGS) deployed a transportable Doppler radar during the precursory stage of the 2009 eruption of Redoubt Volcano, Alaska, and it provided valuable information during subsequent explosive events. We describe the capabilities of this new monitoring tool and present data that it captured during the Redoubt eruption. The volcano-monitoring Doppler radar operates in the C-band (5.36 cm) and has a 2.4-m parabolic antenna with a beam width of 1.6 degrees, a transmitter power of 330 watts, and a maximum effective range of 240 km. The entire disassembled system, including a radome, fits inside a 6-m-long steel shipping container that has been modified to serve as base for the antenna/radome, and as a field station for observers and other monitoring equipment. The radar was installed at the Kenai Municipal Airport, 82 km east of Redoubt and about 100 km southwest of Anchorage. In addition to an unobstructed view of the volcano, this secure site offered the support of the airport staff and the City of Kenai. A further advantage was the proximity of a NEXRAD Doppler radar operated by the Federal Aviation Administration. This permitted comparisons with an established weather-monitoring radar system. The new radar system first became functional on March 20, roughly a day before the first of nineteen explosive ash-producing events of Redoubt between March 21 and April 4. Despite inevitable start-up problems, nearly all of the events were observed by the radar, which was remotely operated from the Alaska Volcano Observatory office in Anchorage. The USGS and NEXRAD radars both detected the eruption columns and tracked the directions of drifting ash clouds. The USGS radar scanned a 45-degree sector centered on the volcano while NEXRAD scanned a full 360 degrees. The sector strategy scanned the volcano more frequently than the 360-degree strategy. Consequently, the USGS system detected event onset within less than a minute, while the NEXRAD required about 4 minutes. The observed column heights were as high as 20 km above sea level and compared favorably to those from NEXRAD. NEXRAD tracked ash clouds to greater distances than the USGS system. This experience shows that Doppler radar is a valuable complement to traditional seismic and satellite monitoring of explosive eruptions.
Impulse radar imaging system for concealed object detection
NASA Astrophysics Data System (ADS)
Podd, F. J. W.; David, M.; Iqbal, G.; Hussain, F.; Morris, D.; Osakue, E.; Yeow, Y.; Zahir, S.; Armitage, D. W.; Peyton, A. J.
Electromagnetic systems for imaging concealed objects at checkpoints typically employ radiation at millimetre and terahertz frequencies. These systems have been shown to be effective and provide a sufficiently high resolution image. However there are difficulties and current electromagnetic systems have limitations particularly in accurately differentiating between threat and innocuous objects based on shape, surface emissivity or reflectivity, which are indicative parameters. In addition, water has a high absorption coefficient at millimetre wavelength and terahertz frequencies, which makes it more difficult for these frequencies to image through thick damp clothing. This paper considers the potential of using ultra wideband (UWB) in the low gigahertz range. The application of this frequency band to security screening appears to be a relatively new field. The business case for implementing the UWB system has been made financially viable by the recent availability of low-cost integrated circuits operating at these frequencies. Although designed for the communication sector, these devices can perform the required UWB radar measurements as well. This paper reports the implementation of a 2 to 5 GHz bandwidth linear array scanner. The paper describes the design and fabrication of transmitter and receiver antenna arrays whose individual elements are a type of antipodal Vivaldi antenna. The antenna's frequency and angular response were simulated in CST Microwave Studio and compared with laboratory measurements. The data pre-processing methods of background subtraction and deconvolution are implemented to improve the image quality. The background subtraction method uses a reference dataset to remove antenna crosstalk and room reflections from the dataset. The deconvolution method uses a Wiener filter to "sharpen" the returned echoes which improves the resolution of the reconstructed image. The filter uses an impulse response reference dataset and a signal-to-noise parameter to determine how the frequencies contained in the echo dataset are normalised. The chosen image reconstruction algorithm is based on the back-projection method. The algorithm was implemented in MATLAB and uses a pre-calculated sensitivity matrix to increase the computation speed. The results include both 2D and 3D image datasets. The 3D datasets were obtained by scanning the dual sixteen element linear antenna array over the test object. The system has been tested on both humans and mannequin test objects. The front surface of an object placed on the human/mannequin torso is clearly visible, but its presence is also seen from a tell-tale imaging characteristic. This characteristic is caused by a reduction in the wave velocity as the electromagnetic radiation passes through the object, and manifests as an indentation in the reconstructed image that is readily identifiable. The prototype system has been shown to easily detect a 12 mm x 30 mm x70 mm plastic object concealed under clothing.
Measurement of sea and ice backscatter reflectivity using an OTH radar system
NASA Astrophysics Data System (ADS)
Ring, W. F.; Sales, G. S.
It is essential, during the operation of an OTH-radar system designed for the detection of small targets (aircraft or cruise missiles), that the operators be able to estimate the system sensitivity in real time without targets present. In geographical areas under surveillance that are remote and inaccessible, this technique involves measuring the ratio of the signal returned from the 'ground' to the noise signal. Data from Polar Fox II experimental OTH-radar system was analyzed in order to determine the intrinsic backscatter reflectivity from open ocean, sea ice, and the Greenland ice cap.
Weather Radar and Instrumentation: Laboratory Modules
NSDL National Science Digital Library
These 16 radar education modules, developed for the Weather Radar and Instrumentation Curriculum at the University of Oklahoma, provide hands-on instruction for beginning, intermediate, or advanced students to learn about radar systems, especially weather radar. Topics include hardware, weather radar, adaptive systems, advanced hydrometeors, applications of weather radar, and atmospheric interpretations. The modules may be downloaded.
Multiple-scattering in radar systems: A review
Alessandro Battaglia; Simone Tanelli; Satoru Kobayashi; Dusan Zrnic; Robin J. Hogan; Clemens Simmer
Although extensively studied within the lidar community, the multiple scattering phenomenon has always been considered a rare curiosity by radar meteorologists. Up to few years ago its appearance has only been associated with two- or three-body-scattering features (e.g. hail flares and mirror images) involving highly reflective surfaces.Recent atmospheric research aimed at better understanding of the water cycle and the role
On the Use of Low-Cost Radar Networks for Collision Warning Systems Aboard Dumpers
Gonz�lez-Partida, Jos�-Tom�s; Le�n-Infante, Francisco; Bl�zquez-Garc�a, Rodrigo; Burgos-Garc�a, Mateo
The use of dumpers is one of the main causes of accidents in construction sites, many of them with fatal consequences. These kinds of work machines have many blind angles that complicate the driving task due to their large size and volume. To guarantee safety conditions is necessary to use automatic aid systems that can detect and locate the different objects and people in a work area. One promising solution is a radar network based on low-cost radar transceivers aboard the dumper. The complete system is specified to operate with a very low false alarm rate to avoid unnecessary stops of the dumper that reduce its productivity. The main sources of false alarm are the heavy ground clutter, and the interferences between the radars of the network. This article analyses the clutter for LFM signaling and proposes the use of Offset Linear Frequency Modulated Continuous Wave (OLFM-CW) as radar signal. This kind of waveform can be optimized to reject clutter and self-interferences. Jointly, a data fusion chain could be used to reduce the false alarm rate of the complete radar network. A real experiment is shown to demonstrate the feasibility of the proposed system. PMID:24577521
System Concepts for the Advanced Post-TRMM Rainfall Profiling Radars
NASA Technical Reports Server (NTRS)
Im, Eastwood; Smith, Eric A.
Global rainfall is the primary distributor of latent heat through atmospheric circulation. The recently launched Tropical Rainfall Measuring Mission satellite is dedicated to advance our understanding of tropical precipitation patterns and their implications on global climate and its change. The Precipitation Radar (PR) aboard the satellite is the first radar ever flown in space and has provided. exciting, new data on the 3-D rain structures for a variety of scientific uses. However, due to the limited mission lifetime and the dynamical nature of precipitation, the TRMM PR data acquired cannot address all the issues associated with precipitation, its related processes, and the long-term climate variability. In fact, a number of new post-TRMM mission concepts have emerged in response to the recent NASA's request for new ideas on Earth science missions at the post 2002 era. This paper will discuss the system concepts for two advanced, spaceborne rainfall profiling radars. In the first portion of this paper, we will present a system concept for a second-generation spaceborne precipitation radar for operations at the Low Earth Orbit (LEO). The key PR-2 electronics system will possess the following capabilities: (1) A 13.6/35 GHz dual frequency radar electronics that has Doppler and dual-polarization capabilities. (2) A large but light weight, dual-frequency, wide-swath scanning, deployable antenna. (3) Digital chirp generation and the corresponding on-board pulse compression scheme. This will allow a significant improvement on rain signal detection without using the traditional, high-peak-power transmitters and without sacrificing the range resolution. (4) Radar electronics and algorithm to adaptively scan the antenna so that more time can be spent to observe rain rather than clear air. and (5) Built-in flexibility on the radar parameters and timing control such that the same radar can be used by different future rain missions. This will help to reduce the overall instrument development costs. In the second portion of this paper, we will present a system concept for a geostationary rainfall monitoring radar for operations at the geosynchronous Earth Orbit (GEO). In particular, the science requirements, the observational strategy, the instrument design, and the required technologies will be discussed.
Radar velocity-measuring system design and computation algorithm based on ARM processor
Yi Zeng; Jianmin Xu; Deng Peng
The real-time monitoring of vehicles velocity has become essential for traffic safety. Therefore, in order to improve the method of monitoring the velocity of vehicles on road, this paper has designed a new radar velocity-measuring system which is based on ARM processor. This system is based on Doppler principle and spectral estimation algorithm, in its hardware design part, and it
Development of the Integrated Target Information System of the Marine Radar and AIS Based on ECDIS
Lin Changchuan; Lin Hai; Li Lina; Zhou Jianwen; Ou Yangping
AIS (automatic identification system), a new type of marine equipment, together with radar, are all the key navaid for a ship to navigate. Now in the seafaring, it is one of the most attentive research issues how to adequately and effectively use their information to improve the sail safety. The paper developed the integrated target information system based on ECDIS
Analysis of the exposure levels and potential biological effects of the PAVE PAWS radar system
S. F. Cleary; W. R. Adey; O. P. Gandhi; D. R. Justesen; B. McMillan; S. Warren; C. S. White; G. M. Wilkening; A. W. Guy; D. E. Janes
The Panel on the Extent of Radiation from the PAVE PAWS Radar System was charged to examine the extent of radiation and the exposure of the public to radiation from the PAVE PAWS system. In carrying out this task, the Panel has considered the characteristics of the PAVE PAWS radiation as related to public exposure and compared the possible exposure
The Design and Development of a Hybrid RF/Laser Radar System for Measuring Changes in
Kansas, University of
of varying NEP on the minimum detectable optical input power for the system ......................................................... 40 4.6 The Effects of varying local oscillator, P_lo, on the minimum detectable optical input powerThe Design and Development of a Hybrid RF/Laser Radar System for Measuring Changes in Ice Surface
Application of the gold ring bundles for innovative non-redundant radar or sonar systems
V. Riznyk; O. Bandyrska
.��The paper involves techniques for configure planar \\u000a space-tapered arrays of radar or sonar system, using novel designs based on \\u000a the concept of Gold Ring Bundles (GRB)s for finding the optimal placement of \\u000a array antenna elements in the system with respect to resolving ability.
Vertical profiles of radar reflectivity of convective cells in tropical and mid-latitude mesoscale convective systems
Lutz, Kurt Reed
in Tropical and Mid-latitude Mesoscale Convective Systems. (December 1992) Kurt Reed Lutz, B. S. , Central Michigan University Chair of Advisory Committee: Dr. Edward J. Zipser This study uses ref lectivity data from Doppler radars to construct vertical... profiles of radar ref lectivity of convective cells observed in three different environmental regimes. The NCAR CP-3 and CP-4 Doppler radars are used to build mean and median ref lectivity profiles of cells observed in the convective region of mid...
SAR (Synthetic Aperture Radar). Earth observing system. Volume 2F: Instrument panel report
NASA Technical Reports Server (NTRS)
The scientific and engineering requirements for the Earth Observing System (EOS) imaging radar are provided. The radar is based on Shuttle Imaging Radar-C (SIR-C), and would include three frequencies: 1.25 GHz, 5.3 GHz, and 9.6 GHz; selectable polarizations for both transmit and receive channels; and selectable incidence angles from 15 to 55 deg. There would be three main viewing modes: a local high-resolution mode with typically 25 m resolution and 50 km swath width; a regional mapping mode with 100 m resolution and up to 200 km swath width; and a global mapping mode with typically 500 m resolution and up to 700 km swath width. The last mode allows global coverage in three days. The EOS SAR will be the first orbital imaging radar to provide multifrequency, multipolarization, multiple incidence angle observations of the entire Earth. Combined with Canadian and Japanese satellites, continuous radar observation capability will be possible. Major applications in the areas of glaciology, hydrology, vegetation science, oceanography, geology, and data and information systems are described.
GEOS-2 C-band system project. C-band radars and their use on the GEOS-2 project
NASA Technical Reports Server (NTRS)
The material presented covers the general topic of C-band radars and their use throughout the GEOS-2 C-band Radar System Project and has direct application to the general problem of gathering accurate radar tracking data. The material is hardware oriented and all analyses and evaluations described pertain to the gathering of accurate data rather than to the application of the gathered data. The radar oriented investigations formed a basic and necessary part of the overall C-band experiment. The successful completion of these efforts led to the definition of how the radars were to be operated and calibrated. These hardware decisions directly affected the quality of the radar data and therefore played a large part in the successful application of these data to geodetic research.
Acquisition and use of Orlando, Florida and Continental Airbus radar flight test data
NASA Technical Reports Server (NTRS)
Eide, Michael C.; Mathews, Bruce
Westinghouse is developing a lookdown pulse Doppler radar for production as the sensor and processor of a forward looking hazardous windshear detection and avoidance system. A data collection prototype of that product was ready for flight testing in Orlando to encounter low level windshear in corroboration with the FAA-Terminal Doppler Weather Radar (TDWR). Airborne real-time processing and display of the hazard factor were demonstrated with TDWR facilitated intercepts and penetrations of over 80 microbursts in a three day period, including microbursts with hazard factors in excess of .16 (with 500 ft. PIREP altitude loss) and the hazard factor display at 6 n.mi. of a visually transparent ('dry') microburst with TDWR corroborated outflow reflectivities of +5 dBz. Range gated Doppler spectrum data was recorded for subsequent development and refinement of hazard factor detection and urban clutter rejection algorithms. Following Orlando, the data collection radar was supplemental type certified for in revenue service on a Continental Airlines Airbus in an automatic and non-interferring basis with its ARINC 708 radar to allow Westinghouse to confirm its understanding of commercial aircraft installation, interface realities, and urban airport clutter. A number of software upgrades, all of which were verified at the Receiver-Transmitter-Processor (RTP) hardware bench with Orlando microburst data to produce desired advanced warning hazard factor detection, included some preliminary loads with automatic (sliding window average hazard factor) detection and annunciation recording. The current (14-APR-92) configured software is free from false and/or nuisance alerts (CAUTIONS, WARNINGS, etc.) for all take-off and landing approaches, under 2500 ft. altitude to weight-on-wheels, into all encountered airports, including Newark (NJ), LAX, Denver, Houston, Cleveland, etc. Using the Orlando data collected on hazardous microbursts, Westinghouse has developed a lookdown pulse Doppler radar product with signal and data processing algorithms which detect realistic microburst hazards and has demonstrated those algorithms produce no false alerts (or nuisance alerts) in urban airport ground moving vehicle (GMTI) and/or clutter environments.
UWB RADAR Receiver Architecture
Nuno Paulino; Adolfo Steiger Gar��o; Jo�o Goes
this chapter describes the operation of a radar system. The differences and advantages of using UWB signals in the radar system,\\u000a over traditional narrow band signals, are discussed. The radar equation, usually defined for narrow band signals, is redefined\\u000a for UWB signals. This new radar equation is used to analyze the echo signals from targets with basic shapes, resulting in
Considerations for a Radar System to Detect an Ocean Underneath the Icy Shell of Europa
NASA Technical Reports Server (NTRS)
Markus, Thorsten; Gogineni, Prasad; Green, James; Cooper, John; Fung, Shing; Taylor, William; Benson, Robert; Reinisch, Bodo; Song, Paul
The detection of an ocean underneath Europa is one of the primary objectives of the Jupiter Icy Moons Orbiter (JIMO) mission. An orbiting surface penetrating radar has the potential of providing that measurement thus yielding information regarding the possibility of life support on Europa. Radars in the MHz range have successfully monitored the kilometer-deep ice shelves of Greenland and Antarctica, including the detection of Lake Vostok (and others) below an ice sheet thickness of about 4 km. The performance of a radar system orbiting Europa will be subject to several potential complications and unknowns. Besides ionospheric dispersion and the actual depth of the ocean, which is estimated between 2 and 30 km, major unknowns affecting radar performance are the temperature profile, the amount of salt and other impurities within the ice crust as well as the surface roughness. These impurities can in part be produced at the highly irradiated surface by magnetospheric interactions and transported downward into the ice crust by geologic processes. The ionospheric interference must also be modeled from effects of these interactions on production of the thin neutral atmosphere and subsequent ionization of the neutrals. We investigated these uncertainties through radar simulations using different surface and ice characteristics over a frequency range from 10 to 50 MHz. The talk will present results from these simulations discussing potential limitations.
Design of integrated ship monitoring system using SAR, RADAR, and AIS
NASA Astrophysics Data System (ADS)
Yang, Chan-Su; Kim, Tae-Ho; Hong, Danbee; Ahn, Hyung-Wook
When we talk about for the ship detection, identification and its classification, we need to go for the wide area of monitoring and it may be possible only through satellite based monitoring approach which monitors and covers coastal as well as the oceanic zone. Synthetic aperture radar (SAR) has been widely used to detect targets of interest with the advantage of the operating capability in all weather and luminance free condition (Margarit and Tabasco, 2011). In EU waters, EMSA(European Maritime Safety Agency) is operating the SafeSeaNet and CleanSeaNet systems which provide the current positions of all ships and oil spill monitoring information in and around EU waters in a single picture to Member States using AIS, LRIT and SAR images. In many countries, a similar system has been developed and the key of the matter is to integrate all available data. This abstract describes the preliminary design concept for an integration system of RADAR, AIS and SAR data for vessel traffic monitoring. SAR sensors are used to acquire image data over large coverage area either through the space borne or airborne platforms in UTC. AIS reports should be also obtained on the same date as of the SAR acquisition for the purpose to perform integration test. Land-based RADAR can provide ships positions detected and tracked in near real time. In general, SAR are used to acquire image data over large coverage area, AIS reports are obtained from ship based transmitter, and RADAR can monitor continuously ships for a limited area. In this study, we developed individual ship monitoring algorithms using RADAR(FMCW and Pulse X-band), AIS and SAR(RADARSAT-2 Full-pol Mode). We conducted field experiments two times for displaying the RADAR, AIS and SAR integration over the Pyeongtaek Port, South Korea.
Global search and rescue - A new concept. [orbital digital radar system with passive reflectors
NASA Technical Reports Server (NTRS)
Sivertson, W. E., Jr.
A new terrestrial search and rescue concept is defined embodying the use of simple passive radiofreqeuncy reflectors in conjunction with a low earth-orbiting, all-weather, synthetic aperture radar to detect, identify, and position locate earth-bound users in distress. Users include ships, aircraft, small boats, explorers, hikers, etc. Airborne radar tests were conducted to evaluate the basic concept. Both X-band and L-band, dual polarization radars were operated simultaneously. Simple, relatively small, corner-reflector targets were successfully imaged and digital data processing approaches were investigated. Study of the basic concept and evaluation of results obtained from aircraft flight tests indicate an all-weather, day or night, global search and rescue system is feasible.
Feature discrimination and detection probability in synthetic aperture radar imaging system
NASA Technical Reports Server (NTRS)
Lipes, R. G.; Butman, S. A.
Images obtained using synthetic aperture radar (SAR) systems can only represent the intensities of resolution cells in the scene of interest probabilistically since radar receiver noise and Rayleigh scattering of the transmitted radiation are always present. Consequently, when features to be identified differ only by their contribution to the mean power of the radar return, discrimination can be treated by detection theory. In this paper, we develop a 'sufficient statistic' for discriminating between competing features and compare it with some suboptimal methods frequently used. Discrimination is measured by probability of detection error and depends on number of samples or 'looks', signal-to-noise ratio (SNR), and ratio of mean power returns from the competing features. Our results show discrimination and image quality rapidly saturate with SNR (very small improvement for SNR not less than 10 dB) but continue to improve with increasing number of looks.
Forth system for coherent-scatter radar data acquisition and processing
NASA Technical Reports Server (NTRS)
Rennier, A. D.; Bowhill, S. A.
A real time collection system was developed for the Urbana coherent scatter radar system. The new system, designed for use with a microcomputer, has several advantages over the old system implemented with a minicomputer. The software used to collect the data is described as well as the processing software used to analyze the data. In addition a magnetic tape format for coherent scatter data exchange is given.
Design and Analysis of Wideband Antenna with Application to Ground Penetrating Radar System
G. E. Atteia; K. F. A. Hussein; A. A. Shaalan
In this paper, a wide band antenna is proposed for ground-penetrating radar (GPR) system. This antenna consists of dipole antenna housed in a rectangular conducting reflector whose inner walls are coated by an absorbing material. The coating is composed of a number of layers with a conductivity profile designed to achieve the minimum voltage standing wave ratio (VSWR) of the
Target location and speed estimation by multistatic radar system using maximum likelihood approach
Yang Wenlin; Wei Chongyu
This paper describes a short range target location and speed estimation using the maximum likelihood method based on the range difference information of a T-R multistatic radar system transmitting a new grouped waveform of FMCW signal and single carrier pulse. Formulae are derived independent of transmitter position. Performances are simulated with the proposed algorithm and results are given for various
Analysis of Radiation Pattern of Radar Systems Based on Leaky Coaxial Cables
N. Blaunstein; Z. Dank; M. Zilbershtein
Theoretical and numerical analyses of the radiation directivity of a guided radar system based on leaky coaxial cable (LCC) are presented both for buried and open installations in clutter conditions. The theoretical model of fields generated by a cable buried in a lossy half-space, such as a sub-soil medium, is introduced to describe the working characteristics of such a leaky
Wave pattern of a leaky coaxial cable in a guiding radar system under various clutter conditions
Nathan S. Blaunstein; Z. Dank; M. Zilbershtein
Theoretical and numerical analyses of the radiation directivity of a guiding radar system based on leaky coaxial cable (LCC) are presented both for buried and open installations in clutter conditions. The theoretical model of fields generated by a cable buried in a lossy half-space, such as a sub-soil medium, is introduced to describe the working characteristics of such a leaky
ECE 686: Introduction to Radar Systems Department of Electrical & Computer Engineering
Massachusetts at Amherst, University of
, detection and receiver design, transmitters and antenna systems. Applications surveyed include pulsed, CW., 1993, Academic Press, ISBN 0-12-221422-6. "Microwave Remote Sensing, Active & Passive Vol. II, Radar Remote Sensing and Sur- face Scattering and Emission Theory", F.T. Ulaby, R.K. Moore, A.K. Fung, 1986
An autonomous, non-cooperative, wide-area traffic monitoring system using space-based radar (TRAMRAD)
D. Hounam; S. Baumgartner; K. H. Bethke; M. Gabele; E. Kemptner; D. Klement; G. Krieger; G. Rode; K. Wagel
To meet the challenges of ever increasing road traffic and the associated economic and sociological impacts, new techniques and technologies for better traffic management are needed. The TRAMRAD project (Traffic Monitoring with space-based Radar) aims to profit from research and development in earth observation and advances in radar remote sensing techniques to define a future space-based sensor system for the
Radar remote sensing in biology
Moore, Richard K.; Simonett, David S.
The present status of research on discrimination of natural and cultivated vegetation using radar imaging systems is sketched. The value of multiple polarization radar in improved discrimination of vegetation types over monoscopic radars is also documented. Possible future use of multi-frequency, multi-polarization radar systems for all weather agricultural survey is noted.
Data Acquisition System for Multi-Frequency Radar Flight Operations Preparation
NASA Technical Reports Server (NTRS)
Leachman, Jonathan
A three-channel data acquisition system was developed for the NASA Multi-Frequency Radar (MFR) system. The system is based on a commercial-off-the-shelf (COTS) industrial PC (personal computer) and two dual-channel 14-bit digital receiver cards. The decimated complex envelope representations of the three radar signals are passed to the host PC via the PCI bus, and then processed in parallel by multiple cores of the PC CPU (central processing unit). The innovation is this parallelization of the radar data processing using multiple cores of a standard COTS multi-core CPU. The data processing portion of the data acquisition software was built using autonomous program modules or threads, which can run simultaneously on different cores. A master program module calculates the optimal number of processing threads, launches them, and continually supplies each with data. The benefit of this new parallel software architecture is that COTS PCs can be used to implement increasingly complex processing algorithms on an increasing number of radar range gates and data rates. As new PCs become available with higher numbers of CPU cores, the software will automatically utilize the additional computational capacity.
Decision making for urban drainage systems under uncertainty caused by weather radar rainfall measurement
NASA Astrophysics Data System (ADS)
Dai, Qiang; Zhuo, Lu; Han, Dawei
With the rapidly growth of urbanization and population, the decision making for managing urban flood risk has been a significant issue for most large cities in China. A high-quality measurement of rainfall at small temporal but large spatial scales is of great importance to urban flood risk management. Weather radar rainfall, with its advantage of short-term predictability and high spatial and temporal resolutions, has been widely applied in the urban drainage system modeling. It is recognized that weather radar is subjected to many uncertainties and many studies have been carried out to quantify these uncertainties in order to improve the quality of the rainfall and the corresponding outlet flow. However, considering the final action in urban flood risk management is the decision making such as flood warning and whether to build or how to operate a hydraulics structure, some uncertainties of weather radar may have little or significant influence to the final results. For this reason, in this study, we aim to investigate which characteristics of the radar rainfall are the significant ones for decision making in urban flood risk management. A radar probabilistic quantitative rainfall estimated scheme is integrated with an urban flood model (Storm Water Management Model, SWMM) to make a decision on whether to warn or not according to the decision criterions. A number of scenarios with different storm types, synoptic regime and spatial and temporal correlation are designed to analyze the relationship between these affected factors and the final decision. Based on this, parameterized radar probabilistic rainfall estimation model is established which reflects the most important elements in the decision making for urban flood risk management.
An Airborne Radar System for High-Resolution Mapping of Internal Layers P. Kanagaratnam, R. Eakin and S.P. Gogineni
Kansas, University of
An Airborne Radar System for High-Resolution Mapping of Internal Layers P. Kanagaratnam, R. Eakin and S.P. Gogineni The University of Kansas, Radar Systems and Remote Sensing Laboratory 2335 Irving Hill the use of high- resolution radars for mapping of near-surface internal layers and generating continuous
The 94 GHz Cloud Radar System on a NASA ER-2 Aircraft
NASA Technical Reports Server (NTRS)
Li, Lihua; Heymsfield, Gerald M.; Racette, Paul E.; Tian, Lin; Zenker, Ed
The 94-GHz (W-band) Cloud Radar System (CRS) has been developed and flown on a NASA ER-2 high-altitude (20 km) aircraft. The CRS is a fully coherent, polarimeteric Doppler radar that is capable of detecting clouds and precipitation from the surface up to the aircraft altitude in the lower stratosphere. The radar is especially well suited for cirrus cloud studies because of its high sensitivity and fine spatial resolution. This paper describes the CRS motivation, instrument design, specifications, calibration, and preliminary data &om NASA s Cirrus Regional Study of Tropical Anvils and Cirrus Layers - Florida Area Cirrus Experiment (CRYSTAL-FACE) field campaign. The unique combination of CRS with other sensors on the ER-2 provides an unprecedented opportunity to study cloud radiative effects on the global energy budget. CRS observations are being used to improve our knowledge of atmospheric scattering and attenuation characteristics at 94 GHz, and to provide datasets for algorithm implementation and validation for the upcoming NASA CloudSat mission that will use a 94-GHz spaceborne cloud radar to provide the first direct global survey of the vertical structure of cloud systems.
Analysis of phase relationships between radar signals in acoustooptic processing systems
M. V. D�yakonov; T. F. Fa�sullov; T. T. Sultanov; A. F. Tavasiev; A. N. Torgashin; V. A. Zubov
The performance and the salient operation features of an interference correlator with a modified optical twin-wave Rayleigh\\u000a interferometer system in the mode of measurements of phase shifts between radar signals are considered. Such measurements\\u000a for signals received from two antennas provide information on the angular position of an object or its displacement. A system\\u000a wherein radio signals are fed for
Two-Dimensional Imaging via a Narrowband MIMO Radar System With Two Perpendicular Linear Arrays
Dang-Wei Wang; Xiao-Yan Ma; Yi Su
This paper presents a system model and method for the 2-D imaging application via a narrowband multiple-input multiple-output (MIMO) radar system with two perpendicular linear arrays. Furthermore, the imaging formulation for our method is developed through a Fourier integral processing, and the parameters of antenna array including the cross-range resolution, required size, and sampling interval are also examined. Different from
M. C. Teich
The operation of a three-frequency heterodyne system for communications and radar use is discussed. The technique provides important advantages over the conventional heterodyne detector, and is applicable in the infrared, optical, and microwave. The signal-to-noise ratio and minimum detectable power for the specific case of an optical or infrared system are calculated and compared with values for the standard configuration.
Parallel processing in a host plus multiple array processor system for radar
NASA Technical Reports Server (NTRS)
Barkan, B. Z.
Host plus multiple array processor architecture is demonstrated to yield a modular, fast, and cost-effective system for radar processing. Software methodology for programming such a system is developed. Parallel processing with pipelined data flow among the host, array processors, and discs is implemented. Theoretical analysis of performance is made and experimentally verified. The broad class of problems to which the architecture and methodology can be applied is indicated.
Radar systems for a polar mission, volume 3, appendices A-D, S, T
NASA Technical Reports Server (NTRS)
Moore, R. K.; Claassen, J. P.; Erickson, R. L.; Fong, R. K. T.; Hanson, B. C.; Komen, M. J.; Mcmillan, S. B.; Parashar, S. K.
Success is reported in the radar monitoring of such features of sea ice as concentration, floe size, leads and other water openings, drift, topographic features such as pressure ridges and hummocks, fractures, and a qualitative indication of age and thickness. Scatterometer measurements made north of Alaska show a good correlation with a scattering coefficient with apparent thickness as deduced from ice type analysis of stereo aerial photography. Indications are that frequencies from 9 GHz upward seem to be better for sea ice radar purposes than the information gathered at 0.4 GHz by a scatterometer. Some information indicates that 1 GHz is useful, but not as useful as higher frequencies. Either form of like-polarization can be used and it appears that cross-polarization may be more useful for thickness measurement. Resolution requirements have not been fully established, but most of the systems in use have had poorer resolution than 20 meters. The radar return from sea ice is found to be much different than that from lake ice. Methods to decrease side lobe levels of the Fresnel zone-plate processor and to decrease the memory requirements of a synthetic radar processor are discussed.
Multidimensional radar picture
NASA Astrophysics Data System (ADS)
Waz, Mariusz
In marine navigation systems, the three-dimensional (3D) visualization is often and often used. Echosonders and sonars working in hydroacustic systems can present pictures in three dimensions. Currently, vector maps also offer 3D presentation. This presentation is used in aviation and underwater navigation. In the nearest future three-dimensional presentation may be obligatory presentation in displays of navigation systems. A part of these systems work with radar and communicates with it transmitting data in a digital form. 3D presentation of radar picture require a new technology to develop. In the first step it is necessary to compile digital form of radar signal. The modern navigation radar do not present data in three-dimensional form. Progress in technology of digital signal processing make it possible to create multidimensional radar pictures. For instance, the RSC (Radar Scan Converter) - digital radar picture recording and transforming tool can be used to create new picture online. Using RSC and techniques of modern computer graphics multidimensional radar pictures can be generated. The radar pictures mentioned should be readable for ECDIS. The paper presents a method for generating multidimensional radar picture from original signal coming from radar receiver.
Comparative of signal processing techniques for micro-Doppler signature extraction with automotive radar systems
NASA Astrophysics Data System (ADS)
Rodriguez-Hervas, Berta; Maile, Michael; Flores, Benjamin C.
In recent years, the automotive industry has experienced an evolution toward more powerful driver assistance systems that provide enhanced vehicle safety. These systems typically operate in the optical and microwave regions of the electromagnetic spectrum and have demonstrated high efficiency in collision and risk avoidance. Microwave radar systems are particularly relevant due to their operational robustness under adverse weather or illumination conditions. Our objective is to study different signal processing techniques suitable for extraction of accurate micro-Doppler signatures of slow moving objects in dense urban environments. Selection of the appropriate signal processing technique is crucial for the extraction of accurate micro-Doppler signatures that will lead to better results in a radar classifier system. For this purpose, we perform simulations of typical radar detection responses in common driving situations and conduct the analysis with several signal processing algorithms, including short time Fourier Transform, continuous wavelet or Kernel based analysis methods. We take into account factors such as the relative movement between the host vehicle and the target, and the non-stationary nature of the target's movement. A comparison of results reveals that short time Fourier Transform would be the best approach for detection and tracking purposes, while the continuous wavelet would be the best suited for classification purposes.
Embedded DSP-based telehealth radar system for remote in-door fall detection.
Garripoli, Carmine; Mercuri, Marco; Karsmakers, Peter; Jack Soh, Ping; Crupi, Giovanni; Vandenbosch, Guy A E; Pace, Calogero; Leroux, Paul; Schreurs, Dominique
Telehealth systems and applications are extensively investigated nowadays to enhance the quality-of-care and, in particular, to detect emergency situations and to monitor the well-being of elderly people, allowing them to stay at home independently as long as possible. In this paper, an embedded telehealth system for continuous, automatic, and remote monitoring of real-time fall emergencies is presented and discussed. The system, consisting of a radar sensor and base station, represents a cost-effective and efficient healthcare solution. The implementation of the fall detection data processing technique, based on the least-square support vector machines, through a digital signal processor and the management of the communication between radar sensor and base station are detailed. Experimental tests, for a total of 65 mimicked fall incidents, recorded with 16 human subjects (14 men and two women) that have been monitored for 320 min, have been used to validate the proposed system under real circumstances. The subjects' weight is between 55 and 90 kg with heights between 1.65 and 1.82 m, while their age is between 25 and 39 years. The experimental results have shown a sensitivity to detect the fall events in real time of 100% without reporting false positives. The tests have been performed in an area where the radar's operation was not limited by practical situations, namely, signal power, coverage of the antennas, and presence of obstacles between the subject and the antennas. PMID:25291803
A W-Band MMIC Radar System for Remote Detection of Vital Signs
NASA Astrophysics Data System (ADS)
Diebold, Sebastian; Ayhan, Serdal; Scherr, Steffen; Massler, Hermann; Tessmann, Axel; Leuther, Arnulf; Ambacher, Oliver; Zwick, Thomas; Kallfass, Ingmar
In medical and personal health systems for vital sign monitoring, contact-free remote detection is favourable compared to wired solutions. For example, they help to avoid severe pain, which is involved when a patient with burned skin has to be examined. Continuous wave (CW) radar systems have proven to be good candidates for this purpose. In this paper a monolithic millimetre-wave integrated circuit (MMIC) based CW radar system operating in the W-band (75-110 GHz) at 96 GHz is presented. The MMIC components are custom-built and make use of 100 nm metamorphic high electron mobility transistors (mHEMTs). The radar system is employing a frequency multiplier-by-twelve MMIC and a receiver MMIC both packaged in split-block modules. They allow for the determination of respiration and heartbeat frequency of a human target sitting in 1 m distance. The analysis of the measured data is carried out in time and frequency domain and each approach is shown to have its advantages and drawbacks.
Computer simulation of the RF system effects on a millimeter-wave Doppler radar for human vital-signal estimation
Pi-Hsien Lien; Fu-Lin Lin; Huey-Ru Chuang
A detailed modeling and analysis for the effect of the RF system on the human vital-signal estimation by a 60-GHz millimeter-wave Doppler radar has been developed. The simulation scheme uses the root-MUSIC algorithm to calculate the frequency error ratios of the estimated heartbeat and breathing signals by the radar detection system. From the simulation results, it is found that root-MUSIC
A study of an orbital radar mapping mission to Venus. Volume 2: Configuration comparisons and systems evaluation
NASA Technical Reports Server (NTRS)
Configuration comparisons and systems evaluation for the orbital radar mapping mission of the planet Venus are discussed. Designs are recommended which best satisfy the science objectives of the Venus radar mapping concept. Attention is given to the interaction and integration of those specific mission-systems recommendations with one another, and the final proposed designs are presented. The feasibility, cost, and scheduling of these configurations are evaluated against assumptions of reasonable state-of-the-art growth and space funding expectations.
A 77 GHz SiGe power amplifier for potential applications in automotive radar systems
Ullrich R. Pfeiffer; Scott K. Reynolds; Brian A. Floyd
We present the performance of a 77 GHz power amplifier for potential applications directed towards automotive radar systems. The circuit was fabricated in a SiGe bipolar preproduction technology. A balanced two-stage common emitter circuit topology was used to achieve 6.1 dB of power gain at 77 GHz and 11.6 dBm output power at 1dB compression. The power amplifier uses a
Attenuation Margin Requirements in a Networked Radar System for Observation of Precipitation
V. Chandrasekar; Delbert Willie; Yanting Wang; Sanghun Lim; David McLaughlin
In recent years, it becomes increasingly possible to move the operating frequency of weather radar systems from non-attenuating lower frequencies, such as at S-band, to attenuating higher frequencies, such as at X-band. However, wave is more easily extinct in rain at higher frequencies in which case there will be missing observations. Therefore, rain attenuation is one of the important metrics
The EDOP radar system on the high-altitude NASA ER-2 aircraft
Heymsfield, G.M.; Bidwell, S.W.; Caylor, I.J.; Ameen, S.; Nicholson, S.; Boncyk, W.; Miller, L.; Vandemark, D.; Racette, P.E.; Dod, L.R.
The NASA ER-2 high-altitude (20 km) aircraft that emulates a satellite view of precipitation systems carries a variety of passive and active (lidar) remote sensing instruments. A new Doppler weather radar system at X band (9.6 GHz) called the ER-2 Doppler radar (EDOP) has been developed and flown on the ER-2 aircraft. EDOP is a fully coherent Doppler weather radar with fixed nadir and forward pointing (33?? off nadir) beams that map out Doppler winds and reflectivities in the vertical plane along the aircraft motion vector. Doppler winds from the two beams can be used to derive vertical and along-track air motions. In addition, the forward beam provides linear depolarization measurements that are useful in discriminating microphysical characteristics of the precipitation. This paper deals with a general description of the EDOP instrument including the measurement concept, the system configuration and hardware, and recently obtained data examples from the instrument. The combined remote sensing package on the ER-2, along with EDOP, provides a unique platform for simulating spaceborne remote sensing of precipitation.
High resolution system for upper air (troposphere) wind and temperature profile measurements. [meteorological radar/Jimsphere system
NASA Technical Reports Server (NTRS)
Camp, D. W.; Vaughan, W. W.
The Jimsphere/Jimsonde system is described and some possible applications of the system for air-sea interface measurements are presented. As space vehicles became larger and more sophisticated, an improved method for obtaining wind profile data had to be found. To satisfy this need the FPS-16 radar/Jimsphere system was developed. The Jimsphere is an aluminized mylar spherical balloon, two meters in diameter. The balloon is under superpressure, and is tracked with a high precision radar system. The development of this detailed wind profile system was started in 1963, and the present design was established in 1964. To improve the system, a program was initiated in 1965 to obtain high resolution temperature data simultaneously with the wind profile data.
METR 4624--Radar Meteorology SPRING 2012
Droegemeier, Kelvin K.
METR 4624--Radar Meteorology SPRING 2012 Dr. Michael I. Biggerstaff; firstname.lastname@example.com (best method Principles of weather radar and storm observations including: radar system design, em wave propagation, radar&Q, moments of the power spectrum, ground clutter, attenuation, rainfall measurements using radar reflectivity
METR 4624--Radar Meteorology SPRING 2014
Droegemeier, Kelvin K.
METR 4624--Radar Meteorology SPRING 2014 Dr. Michael I. Biggerstaff; firstname.lastname@example.com (best method Principles of weather radar and storm observations including: radar system design, em wave propagation, radar&Q, moments of the power spectrum, ground clutter, attenuation, rainfall measurements using radar reflectivity
Performance Analysis of Pulse Doppler Digital Radars with Application to the Shuttle Ku-Band System
W. K. Alem; C. L. Weber
The performance of a class of pulse Doppler radars with a digitally implemented signal processing unit is investigated. TheKuband rendezvous radar onboard the Shuttle Orbiter is a pulse Doppler radar which is in this class. The detection capability is first presented. A unified analysis of digital radar tracking loops is presented which employs logarithmic discriminants. The results are applied to
Droegemeier, Kelvin K.
apart, these networks defeat the earth curvature blockage that limits today's long-range weather radars;Capsule Summary A new weather radar concept based on dense networks of small radars defeats the earth curvature blockage that limits today's large radars while simultaneously meeting the disparate data needs
Multiple solutions to dense systems in radar scattering using a preconditioned block GMRES solver
Boyse, W.E. [Advanced Software Resources, Inc., Santa Clara, CA (United States)
Multiple right-hand sides occur in radar scattering calculations in the computation of the simulated radar return from a body at a large number of angles. Each desired angle requires a right-hand side vector to be computed and the solution generated. These right-hand sides are naturally smooth functions of the angle parameters and this property is utilized in a novel way to compute solutions an order of magnitude faster than LINPACK The modeling technique addressed is the Method of Moments (MOM), i.e. a boundary element method for time harmonic Maxwell`s equations. Discretization by this method produces general complex dense systems of rank 100`s to 100,000`s. The usual way to produce the required multiple solutions is via LU factorization and solution routines such as found in LINPACK. Our method uses the block GMRES iterative method to directly iterate a subset of the desired solutions to convergence.
Radar-based Flood Warning System for Houston, Texas and Its Performance Evaluation
NASA Astrophysics Data System (ADS)
Fang, N.; Bedient, P.
Houston has a long history of flooding problems as a serious nature. For instance, Houstonians suffered from severe flood inundation during Tropical Storm Allison in 2001 and Hurricane Ike in 2008. Radar-based flood warning systems as non-structural tools to provide accurate and timely warnings to the public and private entities are greatly needed for urban areas prone to flash floods. Fortunately, the advent of GIS, radar-based rainfall estimation using NEXRAD, and real-time delivery systems on the internet have allowed flood alert systems to provide important advanced warning of impending flood conditions. Thus, emergency personnel can take proper steps to mitigate against catastrophic losses. The Rice and Texas Medical Center (TMC) Flood Alert System (FAS2) has been delivering warning information with 2 to 3 hours of lead time to facility personnel in a readily understood format for more than 40 events since 1997. The system performed well during these major rainfall events with R square value of 93%. The current system has been improved by incorporating a new hydraulic prediction tool - FloodPlain Map Library (FPML). The FPML module aims to provide visualized information such as floodplain maps and water surface elevations instead of just showing hydrographs in real time based on NEXRAD radar rainfall data. During Hurricane Ike (September, 2008), FAS2 successfully provided precise and timely flood warning information to TMC with the peak flow difference of 3.6% and the volume difference of 5.6%; timing was excellent for this double-peaked event. With the funding from the Texas Department of Transportation, a similar flood warning system has been developed at a critical transportation pass along Highway 288 in Houston, Texas. In order to enable emergency personnel to begin flood preparation with as much lead time as possible, FAS2 is being used as a prototype to develop warning system for other flood-prone areas such as City of Sugar Land.
REVIEW ARTICLE Interferometric Synthetic Aperture Radar
Kansas, University of
REVIEW ARTICLE Interferometric Synthetic Aperture Radar Christopher T. Allen Department of Electrical Engineering and Computer Science and Radar Systems and Remote Sensing Laboratory University of Kansas Abstract. This paper provides a brief review of interferometric synthetic aperture radar (In
Detection of aquifer system compaction and land subsidence using interferometric synthetic aperture radar, Antelope Valley, Mojave Desert, California
D. L. Galloway; K. W. Hudnut; S. E. Ingebritsen; S. P. Phillips; G. Peltzer; F. Rogez; P. A. Rosen
Interferometric synthetic aperture radar (InSAR) has great potential to detect and quantify land subsidence caused by aquifer system compaction. InSAR maps with high spatial detail and resolution of range displacement (610 mm in change of land surface elevation) were developed for a groundwater basin (;103 km2) in Antelope Valley, California, using radar data collected from the ERS-1 satellite. These data
Principles Involved in the LM Rendezvous Radar Redundant Gyro System
John Dubbuyr
For typical failure rates the probability of two or more of four gyros failing is very much less than one or both of two. Thus, a single redundancy system of four gyros greatly enhances system reliability. The orientation of the sensitive axes of four gyros is specified and means of generating outputs dependent only on gyro inconsistencies are defined. The
A precrash system based on radar for automotive applications
M. Skutek; M. Mekhaiel; G. Wanielik
In present-day cars, safety systems like airbag or seat belt pretensioner reduces accident consequences for passengers. Future generations of cars will support additional safety functions such as precrash, collision warning and broke assistant. For safety functions like precrash the timely deployment of seat belt pretensioner and some other safety systems is important, but is a very difficult problem. In this
Data reduction programs for a laser radar system
NASA Technical Reports Server (NTRS)
Badavi, F. F.; Copeland, G. E.
The listing and description of software routines which were used to analyze the analog data obtained from LIDAR - system are given. All routines are written in FORTRAN - IV on a HP - 1000/F minicomputer which serves as the heart of the data acquisition system for the LIDAR program. This particular system has 128 kilobytes of highspeed memory and is equipped with a Vector Instruction Set (VIS) firmware package, which is used in all the routines, to handle quick execution of different long loops. The system handles floating point arithmetic in hardware in order to enhance the speed of execution. This computer is a 2177 C/F series version of HP - 1000 RTE-IVB data acquisition computer system which is designed for real time data capture/analysis and disk/tape mass storage environment.
VHF/UHF radar observations of tropical mesoscale convective systems over southern India
NASA Astrophysics Data System (ADS)
Kumar, Karanam Kishore; Jain, A. R.; Narayana Rao, D.
Several campaigns have been carried out to study the convective systems over Gadanki (13.5� N, 79.2� E), a tropical station in India, using VHF and UHF radars. The height-time sections of several convective systems are investigated in detail to study reflectivity, turbulence and vertical velocity structure. Structure and dynamics of the convective systems are the main objectives of these campaigns. The observed systems are classified into single- and multi-cell systems. It has been observed that most of the convective systems at this latitude are multi-cellular in nature. Simultaneous VHF and UHF radar observations are used to classify the observed precipitating systems as convective, intermediary and stratiform regions. Composite height profiles of vertical velocities in these regions were obtained and the same were compared with the profiles obtained at other geographical locations. These composite profiles of vertical velocity in the convective regions have shown their peaks in the mid troposphere, indicating that the maximum latent heat is being released at those heights. These profiles are very important for numerical simulations of the convective systems, which vary significantly from one geographical location to the other. Keywords. Meteorology and atmospheric dynamics (Mesoscale meteorology; Convective processes) Radio science (Remote sensing)
Standoff concealed weapon detection using a 350-GHz radar imaging system
NASA Astrophysics Data System (ADS)
Sheen, David M.; Hall, Thomas E.; Severtsen, Ronald H.; McMakin, Douglas L.; Hatchell, Brian K.; Valdez, Patrick L. J.
The sub-millimeter (sub-mm) wave frequency band from 300 - 1000 GHz is currently being developed for standoff concealed weapon detection imaging applications. This frequency band is of interest due to the unique combination of high resolution and clothing penetration. The Pacific Northwest National Laboratory (PNNL) is currently developing a 350 GHz, active, wideband, three-dimensional, radar imaging system to evaluate the feasibility of active sub-mm imaging for standoff detection. Standoff concealed weapon and explosive detection is a pressing national and international need for both civilian and military security, as it may allow screening at safer distances than portal screening techniques. PNNL has developed a prototype active wideband 350 GHz radar imaging system based on a wideband, heterodyne, frequency-multiplier-based transceiver system coupled to a quasi-optical focusing system and high-speed rotating conical scanner. This prototype system operates at ranges up to 10+ meters, and can acquire an image in 10 - 20 seconds, which is fast enough to scan cooperative personnel for concealed weapons. The wideband operation of this system provides accurate ranging information, and the images obtained are fully three-dimensional. During the past year, several improvements to the system have been designed and implemented, including increased imaging speed using improved balancing techniques, wider bandwidth, and improved image processing techniques. In this paper, the imaging system is described in detail and numerous imaging results are presented.
Evaluating a Radar-Based, Non Contact Streamflow Measurement System in the San Joaquin River at Vernalis, California
Cheng, Ralph T.; Gartner, Jeffrey W.; Mason, Robert R.; Costa, John E.; Plant, William J.; Spicer, Kurt R.; Haeni, F. Peter; Melcher, Nick B.; Keller, William C.; Hayes, Ken
Accurate measurement of flow in the San Joaquin River at Vernalis, California, is vital to a wide range of Federal and State agencies, environmental interests, and water contractors. The U.S. Geological Survey uses a conventional stage-discharge rating technique to determine flows at Vernalis. Since the flood of January 1997, the channel has scoured and filled as much as 20 feet in some sections near the measurement site resulting in an unstable stage-discharge rating. In response to recent advances in measurement techniques and the need for more accurate measurement methods, the Geological Survey has undertaken a technology demonstration project to develop and deploy a radar-based streamflow measuring system on the bank of the San Joaquin River at Vernalis, California. The proposed flow-measurement system consists of a ground-penetrating radar system for mapping channel geometries, a microwave radar system for measuring surface velocities, and other necessary infrastructure. Cross-section information derived from ground penetrating radar provided depths similar to those measured by other instruments during the study. Likewise, surface-velocity patterns and magnitudes measured by the pulsed Doppler radar system are consistent with near surface current measurements derived from acoustic velocity instruments. Since the ratio of surface velocity to mean velocity falls to within a small range of theoretical value, using surface velocity as an index velocity to compute river discharge is feasable. Ultimately, the non-contact radar system may be used to make continuous, near-real-time flow measurements during high and medium flows. This report documents the data collected between April 14, 2002 and May 17, 2002 for the purposes of testing this radar based system. Further analyses of the data collected during this field effort will lead to further development and improvement of the system.
Scanning Laser Radar Development for Solar System Exploration Applications
NASA Technical Reports Server (NTRS)
Tratt, D.; Menzies, R.; Bartman, R.; Hemmati, H.
The Jet Propulsion Laboratory (JPL) has recently established an accelerated development initiative to enable high-resolution active optical ranging and terrain mapping capabilities for a series of upcoming Solar System exploration missions.
Sub-Nyquist Radar Sensing Hardware and Supporting System
Eldar, Yonina
between devices Connectivity- AWR RF simulation environment to LabView LabView based GUI Software #12; detected Clutter filtered Supporting Hardware NI System NI 8133 I7 controller Run AWR , LabView and MATLAB
The NASA Dual-Frequency Dual-Polarized Doppler Radar (D3R) System For GPM Ground Validation
NASA Astrophysics Data System (ADS)
Chandrasekar, V.; Schwaller, Mathew; Vega, Manuel; Carswell, James; Vijay Mishra, Kumar; Nguyen, Cuong; Meneghini, Robert; Peterson, Walt
Following on the successful introduction of single-frequency (Ku-Band) weather radar onboard the Tropical Rain Measuring Mission (TRMM) satellite in 1997, the Global Precipitation Measurement (GPM) mission attempts to advance further the goal of making global scale precipitation observations by deploying the next generation of satellite-borne weather radars. The GPM satellite will carry a Ka-Ku band Dual-frequency Precipitation Radar (DPR) that can make measurements of parameters directly related to the microphysics of precipitation (such as raindrop size distribution). The Dual-Frequency Dual-Polarized Doppler Radar (D3R) is a ground validation radar, as a part of the GPM Ground Validation (GV) program, to enable both physical validation support in terms of understanding the microphysical description of the observations as well as algorithm retrieval implications. This paper provides a scientific and technical overview of the D3R system as well as major challenges. The preferred frequency bands of operation for precipitation surveillance in ground radar systems have been nearly non-attenuating frequencies (such as S-, C-band) or short-range measurements of attenuating frequencies (as in X band). However, it is not practical to use traditional ground radar frequencies for precipitation observations in space-borne radars. The GPM mission has embarked on a dual-frequency approach at Ku- and Ka-band for characterizing precipitation. Moving to higher frequencies to observe precipitation though has its own challenges namely, attenuation due to precipitation and reduced Doppler velocity Nyquist limits. Ground radar measurements enjoy the advantage of coincident microphysical observations available to interpret radar signatures but they are currently unavailable at Ku- and Ka-band. An important broader science goal of the NASA D3R is to enhance the database of dual-frequency radar observations on the ground, in conjunction with existing observations, in order to provide a dataset for physical validation basis. Another major advantage of the ground radar observations is the ability to use dual-polarization techniques to yield enhanced microphysical characterization similar to what has been done at lower frequencies. In addition, self-consistency of dual-polarization and dual-frequency observations presents an enhanced level of interpretation, while also providing independent rainfall estimates on the ground. With the ground-based D3R, an independent estimation of hydrometeor classification and drop size distribution retrievals can be done to understand the error structure of retrievals. The dual-frequency ground-based radar provides for various options, including polarimetry and Doppler capabilities. Hence, the name D3R or Dual-frequency Dual-polarized Doppler Radar. Another important engineering aspect of a dual-frequency system is the level of "integration". This can range from a design where two separate radar units operate independently to the one that employs a common reference system for dual-transmitters on a single dual-frequency aperture. The first generation version of the D3R falls somewhere in the middle, i.e., a common platform transmitter illuminating two distinct but aligned antennas. Most of the engineering challenges stem from making precipitation measurements on the ground at a highly attenuating frequency. In order to support the development, extensive numerical evaluations have been carried out to document the extinction statistics of propagation through precipitation. One of the novel aspects of this system is that it employs a solid-state transceiver which supports the deployment in different climactic locations. Thirdly, the dual-frequency dual-polarization operation at higher frequencies involves non-Rayleigh scattering mechanisms and presents different precipitation signatures compared to the conventional S- or C- band observations. The expected observations for this radar based on such scattering and precipitation models are also presented in this paper.
Fiber Optic Systems For Mobile Platforms - A Naval Radar Installation
NASA Astrophysics Data System (ADS)
York, Rich R.
In late 1987, a fiber optic link demonstration was conducted on USS Nimitz (CVN-68) as part of a CNO task to develop standards and specifications for shipboard applications of fiber optics. The demonstration was sponsored by the Naval Sea Systems Command Fiber Optics Program Office (NAVSEA 56ZC) and implemented by the Naval Sea Systems Command Surveillance Systems Subgroup (NAVSEA 62X). The Johns Hopkins University / Applied Physics Laboratory (JHU/APL) was tasked by NAVSEA 62X to serve as principal technical agent for the demonstration. The objective of the project was to demonstrate the practical application of fiber optic technology in a shipboard environment, and to draw lessons applicable to the development of fiber optic standards for shipboard use.
In-Service Evaluation of the Turbulence Auto-PIREP System and Enhanced Turbulence Radar Technologies
NASA Technical Reports Server (NTRS)
Prince, Jason B.; Buck, Bill K.; Robinson, Paul A.; Ryan, Tim
From August 2003 to December 2006, In-Service Evaluations (ISE) of the Turbulence Auto-PIREP System (TAPS) and Enhanced Turbulence (E-Turb) Radar, technologies developed in NASA's Turbulence Prediction and Warning System (TPAWS) element of its Aviation Safety and Security Program (AvSSP), were conducted. NASA and AeroTech Research established an industry team comprising AeroTech, Delta Air Lines, Rockwell Collins, and ARINC to conduct the ISEs. The technologies were installed on Delta aircraft and their effectiveness was evaluated in day-to-day operations. This report documents the establishment and conduct of the ISEs and presents results and feedback from various users.
OWL: an eyesafe 1.5-?m laser radar system for military applications
NASA Astrophysics Data System (ADS)
Eibert, Max; Scherbarth, Stefan
The paper reports on current advances in the development of the Dornier Obstacle Warning System (OWS) for helicopters, with particular emphasis on the Obstacle Warning Ladar (OWL). Here both segments, development and application of the 1.5 micrometer imaging laser radar (LADAR) will be represented. It will be shown how advances in the eyesafe LADAR technology resulted in Obstacle Warning Ladar optimized for wire detection leading to a system family platform covering the range from the commercial needs up to the military requirements.
Dynamics of Satellites in Binary Near-Earth Asteroid Systems: A Study Based on Radar Observations
NASA Astrophysics Data System (ADS)
Naidu, Shantanu
In the past 15 years, three previously unrecognized sub-populations of near-Earth asteroids (NEAs) have been discovered. About 15% of NEAs are binaries, at least 10% of NEAs are contact binaries, and dozens of asteroid pairs have been identified. Numerous science questions have arisen about the formation and evolution processes of these systems and about the inter-relationships between these groups. Addressing these questions informs us about a wide range of important solar system processes that shape small bodies and planetesimals. Here I have chosen to focus on providing one of the most complete characterizations of a binary system among all known asteroid binaries, and on studying the spin-orbit interactions in this and 8 additional binary systems. One hypothesis that has not been fully explored is the possibility of chaotic rotation of asteroid satellites and the impact that such a state has on the evolution of the binary systems. I examine this problem as well as the possibility of detecting librational motions in synchronous satellites. Because the Arecibo and Goldstone radar systems enable superb characterizations of binaries and NEAs in general, this dissertation makes abundant use of radar data. Radar observations provide images of asteroids at decameter resolution, and these images can be inverted to determine the 3D shapes of the components, which are essential to properly model the system dynamics. Radar data also enable precise determination of the mutual orbit, which is another crucial ingredient. In the first two chapters of the dissertation, I describe the observations and physical characterizations of asteroid 2000~ET70 and binary asteroid 2000 DP107. The characterization of 2000 DP107 includes size, shape, spin, mass, and density of each component, making this binary one of the best-characterized asteroid binary to date. In the last chapter of the dissertation, I describe a computationally efficient fourth-order numerical integrator that I used to investigate the coupled spin and orbital dynamics of the satellites of NEAs. The speed of the integrator enabled multi-year timescale simulations of 9 well-characterized binary near-Earth asteroids. The numerical simulations illuminate a range of rotational regimes for asteroid satellites and the conditions under which the various regimes prevail. One of the rotational regimes is chaotic, and I find that this rotation state can substantially delay the radiative evolution of binary systems.
NASA Astrophysics Data System (ADS)
Barton, D. K.
It is pointed out that radar engineers, at the end of 1984, find their field in transition between the conventional designs of the post War II era and the digitally controlled, solid-state systems which will be in place for the year 2000. The U.S. Navy has two major phased array radar systems in operation, including the rotating three-dimensional (3D) AN/SPS-48, and the phased-scanned AN/SPY-1 (Aegis) radars. The Aegis represents a major step beyond the conventional 3D and mechanical fire-control radars. However, it requires a special ship, dedicated to its use. Attention is given to questions regarding an extension of the application of Aegis technology to other U.S. Navy applications and to other navies, an ambitious solid-state radar program in the UK, and Army radars.
Predictability of heavy sub-hourly precipitation amounts for a weather radar based nowcasting system
NASA Astrophysics Data System (ADS)
Bech, Joan; Berenguer, Marc
Heavy precipitation events and subsequent flash floods are one of the most dramatic hazards in many regions such as the Mediterranean basin as recently stressed in the HyMeX (HYdrological cycle in the Mediterranean EXperiment) international programme. The focus of this study is to assess the quality of very short range (below 3 hour lead times) precipitation forecasts based on weather radar nowcasting system. Specific nowcasting amounts of 10 and 30 minutes generated with a nowcasting technique (Berenguer et al 2005, 2011) are compared against raingauge observations and also weather radar precipitation estimates observed over Catalonia (NE Spain) using data from the Meteorological Service of Catalonia and the Water Catalan Agency. Results allow to discuss the feasibility of issuing warnings for different precipitation amounts and lead times for a number of case studies, including very intense convective events with 30minute precipitation amounts exceeding 40 mm (Bech et al 2005, 2011). As indicated by a number of verification scores single based radar precipitation nowcasts decrease their skill quickly with increasing lead times and rainfall thresholds. This work has been done in the framework of the Hymex research programme and has been partly funded by the ProFEWS project (CGL2010-15892). References Bech J, N Pineda, T Rigo, M Aran, J Amaro, M Gay�, J Ar�s, J Montany�, O van der Velde, 2011: A Mediterranean nocturnal heavy rainfall and tornadic event. Part I: Overview, damage survey and radar analysis. Atmospheric Research 100:621-637 http://dx.doi.org/10.1016/j.atmosres.2010.12.024 Bech J, R Pascual, T Rigo, N Pineda, JM L�pez, J Ar�s, and M Gay�, 2007: An observational study of the 7 September 2005 Barcelona tornado outbreak. Natural Hazards and Earth System Science 7:129-139 http://dx.doi.org/10.5194/nhess-7-129-2007 Berenguer M, C Corral, R Sa0nchez-Diezma, D Sempere-Torres, 2005: Hydrological validation of a radar based nowcasting technique. Journal of Hydrometeorology 6: 532-549 http://dx.doi.org/10.1175/JHM433.1 Berenguer M, D Sempere, G Pegram, 2011: SBMcast - An ensemble nowcasting technique to assess the uncertainty in rainfall forecasts by Lagrangian extrapolation. Journal of Hydrology 404: 226-240 http://dx.doi.org/10.1016/j.jhydrol.2011.04.033
Through-the-wall localization of a moving target by two independent ultra wideband (UWB) radar systems.
Kocur, Du�an; Svecov�, M�ria; Rov?�kov�, Jana
In the case of through-the-wall localization of moving targets by ultra wideband (UWB) radars, there are applications in which handheld sensors equipped only with one transmitting and two receiving antennas are applied. Sometimes, the radar using such a small antenna array is not able to localize the target with the required accuracy. With a view to improve through-the-wall target localization, cooperative positioning based on a fusion of data retrieved from two independent radar systems can be used. In this paper, the novel method of the cooperative localization referred to as joining intersections of the ellipses is introduced. This method is based on a geometrical interpretation of target localization where the target position is estimated using a properly created cluster of the ellipse intersections representing potential positions of the target. The performance of the proposed method is compared with the direct calculation method and two alternative methods of cooperative localization using data obtained by measurements with the M-sequence UWB radars. The direct calculation method is applied for the target localization by particular radar systems. As alternative methods of cooperative localization, the arithmetic average of the target coordinates estimated by two single independent UWB radars and the Taylor series method is considered. PMID:24021968
Compact tile module for S-band AESA radar systems
Niklas Billstr�m; Mattias Nilsson; Per Westling
This paper presents the design and verification of an S-band receiver module for a 2D AESA array. The design includes an S-band chipset and a compact LTCC module using a tile architecture. Even if the primary goal was a system demonstrator, great emphasis was put in achieving a low cost and high manufacturability module concept. The methodology and concept was
G. R. Little
The AN\\/APQ-153 fire control radar modified to provide angle tracking was evaluated for improved performance. The frequency agile modifications are discussed along with the range-rate improvement modifications, and the radar to computer interface. A parametric design and comparison of noncoherent and coherent radar systems are presented. It is shown that the shuttle rendezvous range and range-rate requirements can be made
In-flight detection of errors for enhanced aircraft flight safety and vertical accuracy improvement using digital terrain elevation data with an inertial navigation system, global positioning system and radar altimeter
Robert Anthony Gray
This dissertation discusses integration architectures using digital terrain elevation data (DTED) with an inertial navigation system (INS), a global positioning system (GPS) and a radar altimeter. Two integration architectures are considered: DTED with INS, GPS and radar altimeter for aircraft vertical accuracy improvement during the final approach; and DTED with kinematic GPS (KGPS) and a radar altimeter for enhanced aircraft
Optimal design of reflectometer density profile measurements using a radar systems approach (invited)
Doyle, E.J.; Kim, K.W.; Peebles, W.A.; Rhodes, T.L. [Electrical Engineering Department and Institute of Plasma and Fusion Research, UCLA, Los Angeles, California 90024-1594 (United States)] [Electrical Engineering Department and Institute of Plasma and Fusion Research, UCLA, Los Angeles, California 90024-1594 (United States)
Reflectometry is an attractive and versatile diagnostic technique that can address a wide range of measurement needs on fusion devices. However, progress in the area of profile measurement has been hampered by the lack of a well-understood basis for the optimum design and implementation of such systems. Such a design basis is provided by the realization that reflectometer systems utilized for density profile measurements are in fact specialized forms of radar systems. In this article five criteria are introduced by which reflectometer systems can be systematically designed for optimal performance: range resolution, spatial sampling, turbulence immunity, bandwidth optimization, and the need for adaptive data processing. Many of these criteria are familiar from radar systems analysis, and are applicable to reflectometry after allowance is made for differences stemming from the nature of the plasma target. These criteria are utilized to critically evaluate current reflectometer density profile techniques and indicate improvements that can impact current and next step devices, such as ITER.{copyright} {ital 1997 American Institute of Physics.}
Spatial-spectral processing for imaging systems: Multibeam RF imaging and radar systems using spectral hole burning materials
NASA Astrophysics Data System (ADS)
Braker, Benjamin M.
Systems which form many spatial beams (beamformers) for the RF and microwave spectral bands output either a few simultaneous spatial beams across a wide bandwidth---using true-time-delay beamformers---or many simultaneous spatial beams across a moderate bandwidth---using digital aperture synthesis imagers. The simultaneous spatial beams in true-time-delay beamformers require parallel hardware while digital aperture synthesis imagers requires both high speed digitizers and huge digital processors. Moreover; each output beam is typically processed further by a spectrum analyzer or a radar processor. Simultaneous formation and processing of all spatial beams is intractable for wide bandwidths and many beams. This dissertation develops and demonstrates a new class of photonic processing architectures which form and process many simultaneous, wide bandwidth spatial beams. These photonic architectures modulate RF signals from an emulated array of antennas onto an array of coherent optical carriers. I show the theory, the methods, and the results for systems which use Fourier optics and spectral hole burning (SHB) crystals; the demonstrated applications are: wideband RF imaging, Doppler radar, and multi-static radar applications. Proof-of-concept results show 20-beam RF images across a 1 GHz bandwidth and 20-beam radar correlations across bandwidths up to 150 MHz, but these systems can be scaled to process antenna arrays with thousands of beams across bandwidths up to 20 GHz. While these systems can process wide bandwidths for large antenna arrays, I also show an analysis that claims these systems can offer sensitivity levels comparable to other digital or analog beamformers.
NASA Technical Reports Server (NTRS)
Okamoto, Kenichi
The results of a conceptual design study and the performance of key components of the Bread Board Model (BBM) of the Tropical Rainfall Measuring Mission (TRMM) radar are presented. The radar, which operates at 13.8 GHz and is designed to meet TRMM mission objectives, has a minimum measurable rain rate of 0.5 mm/h with a range resolution of 250 m, a horizontal resolution of about 4 km, and a swath width of 220 km. A 128-element active phased array system is adopted to achieve contiguous scanning within the swath. The basic characteristics of BBM were confirmed by experiments. The development of EM started with the cooperation of NASDA and CRL.
Millimeter Wave Cloud Radar (MMCR) Handbook
KB Widener; K Johnson
The millimeter cloud radar (MMCR) systems probe the extent and composition of clouds at millimeter wavelengths. The MMCR is a zenith-pointing radar that operates at a frequency of 35 GHz. The main purpose of this radar is to determine cloud boundaries (e.g., cloud bottoms and tops). This radar will also report radar reflectivity (dBZ) of the atmosphere up to 20 km. The radar possesses a doppler capability that will allow the measurement of cloud constituent vertical velocities.
Recent results from a nested multi-static HF radar network for the NorthEast Observing System (NEOS)
J. T. Kohut; S. M. Glenn; H. J. Roarty
Summary form only given. Anested HF radar network has been deployed along the New Jersey coast as part of the New Jersey Shelf Observing System (NJSOS) and the larger regional NorthEast Observing System (NEOS). A 25 MHz standard system (range about 50 km) setup for continuous operation since 1999 includes two sites in Brant Beach and Brigantine, New Jersey. A
Digital Terrestrial Video Broadcast Interference Suppression in Forward-Looking Ground Penetrating Radar Systems
NASA Astrophysics Data System (ADS)
Rial, F. I.; Mendez-Rial, Roi; Lawadka, Lukasz; Gonzalez-Huici, Maria A.
In this paper we show how radio frequency interference (RFI) generated by digital video broadcasting terrestrial and digital audio broadcasting transmitters can be an important noise source for forward-looking ground penetrating radar (FLGPR) systems. Even in remote locations the average interference power sometimes exceeds ultra-wideband signals by many dB, becoming the limiting factor in the system sensitivity. The overall problem of RFI and its impact in GPR systems is briefly described and several signal processing approaches to removal of RFI are discussed. These include spectral estimation and coherent subtraction algorithms and various filter approaches which have been developed and applied by the research community in similar contexts. We evaluate the performance of these methods by simulating two different scenarios submitted to real RFI acquired with a FLGPR system developed at the Fraunhofer Institute for High Frequency Physics and Radar Techniques (FHR), (GER). The effectiveness of these algorithms in removing RFI is presented using some performance indices after suppression.
Aeronomy report no. 74: The Urbana meteor-radar system; design, development, and first observations
NASA Technical Reports Server (NTRS)
Hess, G. C.; Geller, M. A.
The design, development, and first observations of a high power meteor-radar system located near Urbana, Illinois are described. The roughly five-fold increase in usable echo rate compared to other facilities, along with automated digital data processing and interferometry measurement of echo arrival angles, permits unsurpassed observations of tidal structure and shorter period waves. Such observations are discussed. The technique of using echo decay rates to infer density and scale height and the method of inferring wind shear from radial acceleration are examined. An original experiment to test a theory of the Delta-region winter anomaly is presented.
Virtual Drive: A Complete V2X Communication and Radar System Simulator for Optimization of Multiple Antenna Systems
Lars Reichardt; J�rgen Maurer; Thomas Fugen; Thomas Zwick
Vehicle-to-X (V2X) communication as well as automotive radar are fast growing areas of consumer interest. This gives rise to a challenge to a well-working communication systems in handling the V2X radio channel. The two most important components influencing the channel are the an- tennas and the fast changing environment, resulting in a time- variant behavior of the channel. Therefore, finding
GMTI Performance Analysis for Circular Scanning SAR Equipped on Slow Platform
Bing Sun; Yinqing Zhou; Jie Chen
Synthetic aperture radar (SAR) equipped on a slow platform has an advantage. It can realize both high resolution and wide swath because of the low pulse repetition frequency. However, there is a serious problem during its application. Even though the swath is very wide, the output speed of azimuth image is equal to the platform's velocity. So it needs too
End-to-end modeling and simulation of GMTI target detection from space
Ryan Luley; John Maher; Robert Hancock; Mark E Davis
The design of space based radars for detection of ground moving targets must consider several factors to be operationally effective. The high speed of the satellite coupled with unknown motion patterns of the ground moving vehicles requires efficient detection and geolocation algorithms, as well as dynamic tasking of the satellite. An end-to-end simulation of the process has been constructed and
Location Detection and Tracking of Moving Targets by a 2D IR-UWB Radar System
Nguyen, Van-Han; Pyun, Jae-Young
In indoor environments, the Global Positioning System (GPS) and long-range tracking radar systems are not optimal, because of signal propagation limitations in the indoor environment. In recent years, the use of ultra-wide band (UWB) technology has become a possible solution for object detection, localization and tracking in indoor environments, because of its high range resolution, compact size and low cost. This paper presents improved target detection and tracking techniques for moving objects with impulse-radio UWB (IR-UWB) radar in a short-range indoor area. This is achieved through signal-processing steps, such as clutter reduction, target detection, target localization and tracking. In this paper, we introduce a new combination consisting of our proposed signal-processing procedures. In the clutter-reduction step, a filtering method that uses a Kalman filter (KF) is proposed. Then, in the target detection step, a modification of the conventional CLEAN algorithm which is used to estimate the impulse response from observation region is applied for the advanced elimination of false alarms. Then, the output is fed into the target localization and tracking step, in which the target location and trajectory are determined and tracked by using unscented KF in two-dimensional coordinates. In each step, the proposed methods are compared to conventional methods to demonstrate the differences in performance. The experiments are carried out using actual IR-UWB radar under different scenarios. The results verify that the proposed methods can improve the probability and efficiency of target detection and tracking. PMID:25808773
Location detection and tracking of moving targets by a 2D IR-UWB radar system.
Nguyen, Van-Han; Pyun, Jae-Young
In indoor environments, the Global Positioning System (GPS) and long-range tracking radar systems are not optimal, because of signal propagation limitations in the indoor environment. In recent years, the use of ultra-wide band (UWB) technology has become a possible solution for object detection, localization and tracking in indoor environments, because of its high range resolution, compact size and low cost. This paper presents improved target detection and tracking techniques for moving objects with impulse-radio UWB (IR-UWB) radar in a short-range indoor area. This is achieved through signal-processing steps, such as clutter reduction, target detection, target localization and tracking. In this paper, we introduce a new combination consisting of our proposed signal-processing procedures. In the clutter-reduction step, a filtering method that uses a Kalman filter (KF) is proposed. Then, in the target detection step, a modification of the conventional CLEAN algorithm which is used to estimate the impulse response from observation region is applied for the advanced elimination of false alarms. Then, the output is fed into the target localization and tracking step, in which the target location and trajectory are determined and tracked by using unscented KF in two-dimensional coordinates. In each step, the proposed methods are compared to conventional methods to demonstrate the differences in performance. The experiments are carried out using actual IR-UWB radar under different scenarios. The results verify that the proposed methods can improve the probability and efficiency of target detection and tracking. PMID:25808773
First Measurements of Aspect Sensitivity of Polar Mesospheric Summer Echoes by a Bistatic Radar System
NASA Astrophysics Data System (ADS)
La Hoz, C.; Pinedo, H.; Havnes, O.; Kosch, M. J.; Senior, A.; Rietveld, M. T.
Polar Mesospheric Summer Echoes (PMSE) have been observed for the first time by a bistatic radar system comprising the EISCAT VHF (224 MHz) active radar in Tromso (Norway) and the receiving EISCAT_3D demonstrator array located in Kiruna, (Sweden). The receiving system is 234 km southeast from the transmitting radar and its line of sight to the mesosphere above Tromso has an elevation angle of 21 degrees implying an aspect angle of the scattered signals in that direction of 69 degrees. This is the first time that a truly bistatic configuration has been employed to measure the angle dependence of the scattering mechanism of PMSE which otherwise has been measured only in monostatic configurations. The bistatic configuration is unencumbered by drawbacks of the monostatic configuration that cannot reach angles greater than about 20 degrees due to antenna beam pattern degradation and the use of models to extrapolate the angle dependence of the scattered signals. Strong scattering was observed over prolonged periods on several days by the demonstrator array in July of 2011. These measurements are at variance with previous aspect angle measurements that have reported aspect angles no greater than about 15 degrees. These results indicate that the turbulent irregularities that produce the scattering have a high degree of isotropy, which is more in line with Kolmogorov's hypothesis of a universal scaling of turbulence based on the assumption of homogeneity and isotropy in the inertial regime of turbulence which applies also to the Batchelor regime (due to large Schmidt numbers) believed to be the case for PMSE.
Collaborative Observations of Near-Earth Asteroids with the Goldstone and Arecibo Radar Systems
NASA Astrophysics Data System (ADS)
Taylor, P. A.
The Goldstone (70-m diameter, 8560 MHz/X band) and Arecibo (305-m diameter, 2380 MHz/S band) solar system radars have long worked independently, yet in tandem, to observe near-Earth asteroids as they make close flybys of Earth. The complementary nature of each site's strengths, Goldstone's maneuverability (and, recently, higher spatial resolution) and Arecibo's higher nominal output power and unmatched collecting area, allow for better constraints on sizes, shapes, spin states, and surface properties of near-Earth asteroids than either system can provide on its own. Here, we will discuss a handful of objects observed with both facilities, including binary asteroids (285263) 1998 QE2 and (153958) 2002 AM31 and contact-binary asteroid (192642) 1999 RD32, and describe how the complementary nature of the Goldstone and Arecibo radars has enhanced our knowledge of these small bodies. The importance of collaboration between Goldstone and Arecibo will only increase in the future as we look to expand the use of high-resolution bistatic observations of near-Earth asteroids, where both sites simultaneously observe a target. Observations this past June during the close flyby of 2014 HQ124 (Benner et al., this meeting) demonstrated reception at Arecibo of a 40-MHz bandwidth (3.75-m resolution), X-band transmission from Goldstone. Future capabilities of the Deep Space Network (Busch et al., this meeting), such as the 80-MHz (1.875-m resolution) radar on the Goldstone 34-m dish, will benefit greatly from the sensitivity of Arecibo's large aperture.
Performance analysis of pulse Doppler digital radars with application to the Shuttle Ku-band system
W. K. Alem; C. L. Weber
A pulse Doppler digital radar is one of the primary components of the Ku-band integrated radar and communication equipment on the Space Shuttle. The performance of the Ku-band rendezvous radar to be used on the Space Shuttle is analyzed in four parts. First an overall functional block diagram description is presented to illustrate the signal processing in the detection and
A Combined Denoising Algorithm Approach to Sea Clutter in Wave Monitoring System by Marine Radar
Yanling Hao; Yanhong Tang; Yi Zhu
X-band marine radar images are usually corrupted by noise due to random interference of electromagnetic waves. The noise degrades the quality of the images and makes interpretations and analysis of marine radar images harder. Therefore, noise reduction is necessary prior to the processing of marine radar images. In this paper a novel combined denoising algorithm approach to sea clutter in
Environmental objections to the PAVE PAWS radar system: a scientific review.
Adair, Robert K
As part of our continental defense system, the United States Air Force has operated a radar system, known generally by the label PAVE PAWS, off of Cape Cod, MA since 1978. Some populated areas in the vicinity of the system are subject to a low level of background radiofrequency radiation from the system, and local citizens' groups have expressed concern that this radiofrequency radiation may affect their health. These concerns have been fueled by presentations and letters by Dr. R. A. Albanese, an applied mathematician at the Air Force Research Laboratory, who has proposed standards by which that PAVE PAWS radiofrequency radiation which is incident on populations should be judged. I discuss those standards that are sufficiently well defined to be subject to analysis and show that they are not based on sound quantitative reasoning. PMID:12492377
NASA Technical Reports Server (NTRS)
Woodman, R. F.
Decoding techniques and equipment used by MST radars are described and some recommendations for new systems are presented. Decoding can be done either by software in special-purpose (array processors, etc.) or general-purpose computers or in specially designed digital decoders. Both software and hardware decoders are discussed and the special case of decoding for bistatic radars is examined.
REVS: a radar-based enhanced vision system for degraded visual environments
NASA Astrophysics Data System (ADS)
Brailovsky, Alexander; Bode, Justin; Cariani, Pete; Cross, Jack; Gleason, Josh; Khodos, Victor; Macias, Gary; Merrill, Rahn; Randall, Chuck; Rudy, Dean
Sierra Nevada Corporation (SNC) has developed an enhanced vision system utilizing fast-scanning 94 GHz radar technology to provide three-dimensional measurements of an aircraft's forward external scene topography. This threedimensional data is rendered as terrain imagery, from the pilot's perspective, on a Head-Up Display (HUD). The image provides the requisite "enhanced vision" to continue a safe approach along the flight path below the Decision Height (DH) in Instrument Meteorological Conditions (IMC) that would otherwise be cause for a missed approach. Terrain imagery is optionally fused with digital elevation model (DEM) data of terrain outside the radar field of view, giving the pilot additional situational awareness. Flight tests conducted in 2013 show that REVS� has sufficient resolution and sensitivity performance to allow identification of requisite visual references well above decision height in dense fog. This paper provides an overview of the Enhanced Flight Vision System (EFVS) concept, of the technology underlying REVS, and a detailed discussion of the flight test results.
Two-dimensional imaging via a narrowband MIMO radar system with two perpendicular linear arrays.
Wang, Dang-wei; Ma, Xiao-yan; Su, Yi
This paper presents a system model and method for the 2-D imaging application via a narrowband multiple-input multiple-output (MIMO) radar system with two perpendicular linear arrays. Furthermore, the imaging formulation for our method is developed through a Fourier integral processing, and the parameters of antenna array including the cross-range resolution, required size, and sampling interval are also examined. Different from the spatial sequential procedure sampling the scattered echoes during multiple snapshot illuminations in inverse synthetic aperture radar (ISAR) imaging, the proposed method utilizes a spatial parallel procedure to sample the scattered echoes during a single snapshot illumination. Consequently, the complex motion compensation in ISAR imaging can be avoided. Moreover, in our array configuration, multiple narrowband spectrum-shared waveforms coded with orthogonal polyphase sequences are employed. The mainlobes of the compressed echoes from the different filter band could be located in the same range bin, and thus, the range alignment in classical ISAR imaging is not necessary. Numerical simulations based on synthetic data are provided for testing our proposed method. PMID:20040416
SEASAT Synthetic Aperture Radar Data
NASA Technical Reports Server (NTRS)
Henderson, F. M.
The potential of radar imagery from space altitudes is discussed and the advantages of radar over passive sensor systems are outlined. Specific reference is made to the SEASAT synthetic aperture radar. Possible applications include oil spill monitoring, snow and ice reconnaissance, mineral exploration, and monitoring phenomena in the urban environment.
A 77 GHz Transceiver for Automotive Radar System Using a120nm In AlAs/In GaAs Metamorphic HEMTs
Kwon, Youngwoo
A 77 GHz Transceiver for Automotive Radar System Using a120nm 0.4 0.35 In AlAs/In GaAs Metamorphic-mail:firstname.lastname@example.com) Abstract -- In this work, we demonstrate a compact 77GHz single-chip transceiver for an automotive radar at the transmitter and a 5dB conversion gain at the receiver. Index Terms -- Automotive radar, 77GHz, MHEMT, MMIC
A System Concept for the Advanced Post-TRMM Rainfall Profiling Radars
NASA Technical Reports Server (NTRS)
Im, Eastwood; Smith, Eric A.
Atmospheric latent heating field is fundamental to all modes of atmospheric circulation and upper mixed layer circulations of the ocean. The key to understanding the atmospheric heating process is understanding how and where precipitation occurs. The principal atmospheric processes which link precipitation to atmospheric circulation include: (1) convective mass fluxes in the form of updrafts and downdrafts; (2) microphysical. nucleation and growth of hydrometeors; and (3) latent heating through dynamical controls on the gravitation-driven vertical mass flux of precipitation. It is well-known that surface and near-surface rainfall are two of the key forcing functions on a number of geophysical parameters at the surface-air interface. Over ocean, rainfall variation contributes to the redistribution of water salinity, sea surface temperature, fresh water supply, and marine biology and eco-system. Over land, rainfall plays a significant role in rainforest ecology and chemistry, land hydrology and surface runoff. Precipitation has also been closely linked to a number of atmospheric anomalies and natural hazards that occur at various time scales, including hurricanes, cyclones, tropical depressions, flash floods, droughts, and most noticeable of all, the El Ninos. From this point of view, the significance of global atmospheric precipitation has gone far beyond the science arena - it has a far-reaching impact on human's socio-economic well-being and sustenance. These and many other science applications require the knowledge of, in a global basis, the vertical rain structures, including vertical motion, rain intensity, differentiation of the precipitating hydrometeors' phase state, and the classification of mesoscale physical structure of the rain systems. The only direct means to obtain such information is the use of a spaceborne profiling radar. It is important to mention that the Tropical Rainfall Measuring Mission (TRMM) have made a great stride forward towards this ultimate goal. The Precipitation Radar (PR) aboard the TRMM satellite is the first ever spaceborne radar dedicated to three-dimensional, global precipitation measurements over the tropics and the subtropics, as well as the detailed synopsis of a wide range of tropical rain storm systems. In only twelve months since launch, the PR, together with other science instruments abroad the satellite have already provided unprecedented insights into the rainfall systems. It is anticipated the a lot more exciting and important rain observations would be made by TRMM throughout its mission duration. While TRMM has provided invaluable data to the user community, it is only the first step towards advancing our knowledge on rain processes and its contributions to climate variability. It is envisioned that a TRMM follow-on mission is needed in such a way to capitalize on the pioneering information provided by TRMM, and its instrument capability must be extended beyond TRMM in such a way to fully address the key science questions from microphysical to climatic time scale. In fact, a number of new and innovative mission concepts have recently put forth for this purpose. Almost all of these new concepts have suggested the utility of a more advanced, high-resolution, Doppler-enabled, vertical profiling radar that can provide multi-parameter observations of precipitation. In this paper, a system concept for a second- gene ration precipitation radar (PR-2) which addresses the above requirements will be described.
Characterization of Adolescent Prescription Drug Abuse and Misuse Using the Researched Abuse Diversion and Addiction-Related Surveillance (RADARS[R]) System
ERIC Educational Resources Information Center
Zosel, Amy; Bartelson, Becki Bucher; Bailey, Elise; Lowenstein, Steven; Dart, Rick
Objective: To describe the characteristics and health effects of adolescent (age 13-19 years) prescription drug abuse and misuse using the Researched Abuse Diversion and Addiction-Related Surveillance (RADARS[R])) System. Method: Secondary analysis of data collected from RADARS System participating poison centers was performed. Data for all�
Micropower impulse radar imaging
Hall, M.S.
From designs developed at the Lawrence Livermore National Laboratory (LLNL) in radar and imaging technologies, there exists the potential for a variety of applications in both public and private sectors. Presently tests are being conducted for the detection of buried mines and the analysis of civil structures. These new systems use a patented ultra-wide band (impulse) radar technology known as Micropower Impulse Radar (GPR) imaging systems. LLNL has also developed signal processing software capable of producing 2-D and 3-D images of objects embedded in materials such as soil, wood and concrete. My assignment while at LLNL has focused on the testing of different radar configurations and applications, as well as assisting in the creation of computer algorithms which enable the radar to scan target areas of different geometeries.
Estimating Reservoir Inflow Using RADAR Forecasted Precipitation and Adaptive Neuro Fuzzy Inference System
NASA Astrophysics Data System (ADS)
Yi, J.; Choi, C.
Rainfall observation and forecasting using remote sensing such as RADAR(Radio Detection and Ranging) and satellite images are widely used to delineate the increased damage by rapid weather changeslike regional storm and flash flood. The flood runoff was calculated by using adaptive neuro-fuzzy inference system, the data driven models and MAPLE(McGill Algorithm for Precipitation Nowcasting by Lagrangian Extrapolation) forecasted precipitation data as the input variables.The result of flood estimation method using neuro-fuzzy technique and RADAR forecasted precipitation data was evaluated by comparing it with the actual data.The Adaptive Neuro Fuzzy method was applied to the Chungju Reservoir basin in Korea. The six rainfall events during the flood seasons in 2010 and 2011 were used for the input data.The reservoir inflow estimation results were comparedaccording to the rainfall data used for training, checking and testing data in the model setup process. The results of the 15 models with the combination of the input variables were compared and analyzed. Using the relatively larger clustering radius and the biggest flood ever happened for training data showed the better flood estimation in this study.The model using the MAPLE forecasted precipitation data showed better result for inflow estimation in the Chungju Reservoir.
Multi-frequency synthetic-aperture imaging with a lightweight ground penetrating radar system
NASA Astrophysics Data System (ADS)
Koppenjan, Steven K.; Allen, Curt M.; Gardner, Duane; Wong, Howard R.; Lee, Hua; Lockwood, Stephanie J.
The detection of buried objects, particularly hazardous waste containers and unexploded ordnance (UXO), has gained significant interest in the Unites States in the late 1990s. The desire to remediate the thousands of sites worldwide has become an increasing concern and the application of radar to this problem has received renewed attention. The US Department of Energy's Special Technologies Laboratory (STL), operated by Bechtel Nevada, has developed several frequency-modulated, continuous-wave (FM-CW) ground penetrating radar (GPR) units. To meet technical requirements for higher-resolution data, STL and the University of California, Santa Barbara (UCSB) is investigating advanced GPR hardware, signal processing, and synthetic-aperture imaging with the development of an innovative system. The goal is to design and fabricate a lightweight, battery-operated unit that does not require surface contact, can be operated by a novice user, and can achieve improved resolution. The latter is accomplished by using synthetic-aperture imaging, which forms the subsurface images by fully utilizing the data sequences collectively along a scan path. We also present the backward propagation algorithm as the basic structure of the multiple-frequency tomographic imaging technique, and the conventional fast Fourier transform (FFT) method which can be described as a degenerated case of the model where the computation procedure is approximated under the narrow-beam assumption.
NSDL National Science Digital Library
Radar tracking used to profile insect migration, mating and flight patterns. Many links to various pages include current workers in radar entomology, historical uses of the technology, and many images.
Design of hybrid optical delay line for automotive radar test system
NASA Astrophysics Data System (ADS)
Son, Byung-Hee; Kim, Kwang-Jin; Li, Ye; Park, Chang-In; Choi, Young-Wan
In this paper, hybrid optical delay line (HODL) which is demanded on automotive radar test system (RTS) is proposed and demonstrated. HODL is composed with coaxial cable in short delay time (< 32 nsec) and optical fiber in long delay time (>= 32 nsec) which are considering the volume, loss and frequency characteristics. Also, the optical transceiver that has the bandwidth of 1 GHz is designed for frequency modulated continuous wave (FMCW). Experimental results show that the S21 is +/- 0.5 dB in the optical transceiver and +/- 1.7 dB in the whole system at 3.7 GHz ~ 4.7 GHz. The resolution of delay time is 1 ns and the delay flatness is +/- 0.23 ns.
Active laser radar systems with stochastic electromagnetic beams in turbulent atmosphere.
Cai, Yangjian; Korotkova, Olga; Eyyubo?lu, Halil T; Baykal, Yahya
Propagation of stochastic electromagnetic beams through paraxial ABCD optical systems operating through turbulent atmosphere is investigated with the help of the ABCD matrices and the generalized Huygens-Fresnel integral. In particular, the analytic formula is derived for the cross-spectral density matrix of an electromagnetic Gaussian Schell-model (EGSM) beam. We applied our analysis for the ABCD system with a single lens located on the propagation path, representing, in a particular case, the unfolded double-pass propagation scenario of active laser radar. Through a number of numerical examples we investigated the effect of local turbulence strength and lens' parameters on spectral, coherence and polarization properties of the EGSM beam. PMID:18825220
The evolution of synthetic aperture radar systems and their progression to the EOS SAR
NASA Technical Reports Server (NTRS)
Way, Jobea; Smith, Elizabeth A.
The authors describe the evolution of the spaceborne imaging radar starting with the Seasat SAR, through the SIR-A, SIR-B, and SIR-C/X-SAR missions, to the Earth Observing System (EOS) SAR which is scheduled for launch as part of EOS in the late 1990s. A summary of the planned international missions, which may produce a permanent active microwave capability in space starting as early as 1991, is also presented, along with a description of the airborne systems which will be essential to the algorithm development and long-term calibration of the spaceborne data. A brief summary of the planetary missions utilizing SAR and a comparison of their imaging capabilities with those available on Earth are presented.
Flom, T
Laser radar systems are being developed to acquire and track targets in applications such as the rendezvous and docking of two spacecraft. To search effectively for and locate a target using a narrow laser beam, a scanning system is needed. This paper describes a scan technique whereby a narrow laser beam is synchronously scanned with an equally narrow receiver field-of-view without the aid of mechanical gimbals. Equations are developed in order to examine the maximum acquisition and tracking rates, and the maximum target range for a scanning laser radar system. A recently built prototype of a small, lightweight, low-power-consuming scanning laser radar is described. PMID:20111497
NASA Technical Reports Server (NTRS)
Sato, Toru
Discussed here is a kind of radar called atmospheric radar, which has as its target clear air echoes from the earth's atmosphere produced by fluctuations of the atmospheric index of refraction. Topics reviewed include the vertical structure of the atmosphere, the radio refractive index and its fluctuations, the radar equation (a relation between transmitted and received power), radar equations for distributed targets and spectral echoes, near field correction, pulsed waveforms, the Doppler principle, and velocity field measurements.
Wave parameters comparisons between High Frequency (HF) radar system and an in situ buoy: a case study
NASA Astrophysics Data System (ADS)
Fernandes, Maria; Alonso-Martirena, Andr�s; Agostinho, Pedro; Sanchez, Jorge; Ferrer, Macu; Fernandes, Carlos
The coastal zone is an important area for the development of maritime countries, either in terms of recreation, energy exploitation, weather forecasting or national security. Field measurements are in the basis of understanding how coastal and oceanic processes occur. Most processes occur over long timescales and over large spatial ranges, like the variation of mean sea level. These processes also involve a variety of factors such as waves, winds, tides, storm surges, currents, etc., that cause huge interference on such phenomena. Measurement of waves have been carried out using different techniques. The instruments used to measure wave parameters can be very different, i.e. buoys, ship base equipment like sonar and satellites. Each equipment has its own advantage and disadvantage depending on the study subject. The purpose of this study is to evaluate the behaviour of a different technology available and presently adopted in wave measurement. In the past few years the measurement of waves using High Frequency (HF) Radars has had several developments. Such a method is already established as a powerful tool for measuring the pattern of surface current, but its use in wave measurements, especially in the dual arrangement is recent. Measurement of the backscatter of HF radar wave provides the raw dataset which is analyzed to give directional data of surface elevation at each range cell. Buoys and radars have advantages, disadvantages and its accuracy is discussed in this presentation. A major advantage with HF radar systems is that they are unaffected by weather, clouds or changing ocean conditions. The HF radar system is a very useful tool for the measurement of waves over a wide area with real-time observation, but it still lacks a method to check its accuracy. The primary goal of this study was to show how the HF radar system responds to high energetic variations when compared to wave buoy data. The bulk wave parameters used (significant wave height, period and direction) were obtained during 2013 and 2014 from one 13.5 MHz CODAR SeaSonde radar station from Hydrographic Institute, located in Espichel Cape (Portugal). These data were compared with those obtained from one wave buoy Datawell Directional Waverider, also from Hydrographic Institute, moored inbound Sines (Portugal) at 100 m depth. For this first approach, was assumed that all the waves are in a deep water situation. Results showed that during high energetic periods, the HF radar system revealed a good correlation with wave buoy data following the bulk wave parameters gradient variations.
Advantages to Geoscience and Disaster Response from QuakeSim Implementation of Interferometric Radar Maps in a GIS Database System
NASA Astrophysics Data System (ADS)
Parker, Jay; Donnellan, Andrea; Glasscoe, Margaret; Fox, Geoffrey; Wang, Jun; Pierce, Marlon; Ma, Yu
High-resolution maps of earth surface deformation are available in public archives for scientific interpretation, but are primarily available as bulky downloads on the internet. The NASA uninhabited aerial vehicle synthetic aperture radar (UAVSAR) archive of airborne radar interferograms delivers very high resolution images (approximately seven meter pixels) making remote handling of the files that much more pressing. Data exploration requiring data selection and exploratory analysis has been tedious. QuakeSim has implemented an archive of UAVSAR data in a web service and browser system based on GeoServer (http://geoserver.org). This supports a variety of services that supply consistent maps, raster image data and geographic information systems (GIS) objects including standard earthquake faults. Browsing the database is supported by initially displaying GIS-referenced thumbnail images of the radar displacement maps. Access is also provided to image metadata and links for full file downloads. One of the most widely used features is the QuakeSim line-of-sight profile tool, which calculates the radar-observed displacement (from an unwrapped interferogram product) along a line specified through a web browser. Displacement values along a profile are updated to a plot on the screen as the user interactively redefines the endpoints of the line and the sampling density. The profile and also a plot of the ground height are available as CSV (text) files for further examination, without any need to download the full radar file. Additional tools allow the user to select a polygon overlapping the radar displacement image, specify a downsampling rate and extract a modest sized grid of observations for display or for inversion, for example, the QuakeSim simplex inversion tool which estimates a consistent fault geometry and slip model.
Regional and Diurnal Variability of the Vertical Structure of Precipitation Systems in Africa Based on Spaceborne Radar Data
Bart Geerts; Teferi Dejene
The Tropical Rainfall Measuring Mission (TRMM) 2A25 radar reflectivity profiles and derived surface rain rates are used to describe the vertical structure of precipitation systems in Africa. Five years of data are used in both the boreal and austral summer rainy seasons. A number of climate regions are isolated and compared. To place the composite reflectivity profiles in context, they
NASA Technical Reports Server (NTRS)
Meneghini, Robert; Kozu, Toshiaki
The present work on the development status of spaceborne weather radar systems and services discusses radar instrument complementarities, the current forms of equations for the characterization of such aspects of weather radar performance as surface and mirror-image returns, polarimetry, and Doppler considerations, and such essential factors in spaceborne weather radar design as frequency selection, scanning modes, and the application of SAR to rain detection. Attention is then given to radar signal absorption by the various atmospheric gases, rain drop size distribution and wind velocity determinations, and the characteristics of clouds, as well as the range of available estimation methods for backscattering, single- and dual-wavelength attenuation, and polarimetric and climatological characteristics.
NSDL National Science Digital Library
This resource provides an introduction to the function and uses of the The National Weather Service's (NWS) Weather Surveillance Doppler Radar (WSR-88D). Topics include the components of the system, an overview of the products and overlays the system creates, and some example images with captions explaining what is being shown. There are also links to radar meteorology tutorials and to information on training to use the system and interpret its imagery.
Millimeter-wave circuits and pulse compression radar baseband/analog signal processing blocks in silicon processes
Parlak, Mehmet; Parlak, Mehmet
pulse compression radar system for the pedes- trian detection sensor. . . . . . . . . . . . . . . . . . . . . . . . .cost pulse radar module for a pedestrian detection sensorpulse compression radar system for the pedestrian de- tection sensor.
Selecting the lorenz parameters for wideband radar waveform generation
Willsey, Matt S.
Radar waveforms based on chaotic systems have occasionally been suggested for a variety of radar applications. In this paper, radar waveforms are constructed with solutions from a particular chaotic system, the Lorenz ...
Bistatic auroral radar system and three-receiver-ionospheric-motions velocities: A comparison
MacDougall, J.W.; Hall, G.E.; Moorcroft, D.R. (Univ. of Western Ontario, London (Canada))
Observations of the NW-SE component of F region convection obtained with a scintillation drift experiment have been compared with power and Doppler velocity measurements of auroral E region coherent backscatter at 50 MHz made with the Bistatic Auroral Radar System (BARS), which is able to observe only at large magnetic aspect angles. It was found that E region backscatter was observed only when the NW-SE component of the F region drift was in the SE direction. This and other observations are shown to be consistent with a recently proposed explanation for these large aspect angle VHF backscatter observations, based on refraction through auroral ionization structures in the E region. In most cases the vector velocity derived from BARS observations had a magnitude substantially below that inferred from the scintillation measurements. Observations during one period were noticeably different from the others, with unusually small Doppler velocities.
Ground penetrating detection using miniaturized radar system based on solid state microwave sensor
NASA Astrophysics Data System (ADS)
Yao, B. M.; Fu, L.; Chen, X. S.; Lu, W.; Guo, H.; Gui, Y. S.; Hu, C.-M.
We propose a solid-state-sensor-based miniaturized microwave radar technique, which allows a rapid microwave phase detection for continuous wave operation using a lock-in amplifier rather than using expensive and complicated instruments such as vector network analyzers. To demonstrate the capability of this sensor-based imaging technique, the miniaturized system has been used to detect embedded targets in sand by measuring the reflection for broadband microwaves. Using the reconstruction algorithm, the imaging of the embedded target with a diameter less than 5 cm buried in the sands with a depth of 5 cm or greater is clearly detected. Therefore, the sensor-based approach emerges as an innovative and cost-effective way for ground penetrating detection.
Use of compact synthetic aperture radar systems to assist with device detection and discrimination
NASA Astrophysics Data System (ADS)
Jensen, Mark; Walls, Thomas J.; Anderson, Scott A.; Linne von Berg, Dale; Holt, Niel; Kruer, Melvin; Long, David G.; Wilson, Michael L.
NuSAR (Naval Research Laboratory Unmanned Synthetic Aperture Radar) is a sensor developed under the ONRfunded FEATHAR (Fusion, Exploitation, Algorithms, and Targeting for High-Altitude Reconnaissance) program. FEATHAR is being directed and executed by the Naval Research Laboratory (NRL) in conjunction with the Space Dynamics Laboratory (SDL). FEATHAR's goal is to develop and test new tactical sensor systems specifically designed for small manned and unmanned platforms (payload weight < 50 lbs). NuSAR is a novel dual-band (L- and X-band) SAR capable of a variety of tactically relevant operating modes and detection capabilities. Flight test results will be described for narrow and wide bandwidth and narrow and wide azimuth aperture operating modes.
High Power mm-Wave Transmitter System for Radar or Telecommunications
NASA Technical Reports Server (NTRS)
Stride, S. L.; McMaster, R. L.; Pogorzelski, R. J.
Future NASA deep space missions able to provide tens of kilo-watts of spacecraft DC power, make it feasible to employ high power RF telecommunications systems. Traditional flight systems (e.g., Cassini), constrained by limited DC power, used a single high-gain 4m Cassegrain reflector fed by a single lower power (20W) transmitter. Increased available DC power means that high power (1000 W) transmitters can be used. Rather than continue building traditional single-transmitter systems it now becomes feasible to engineer and build multi-element active arrays that can illuminate a dish. Illuminating a 2m dish with a spherical wavefront from an offset 1kW active array can provide sufficient ERP (Effective Radiated Power) when compared to a larger Cassegrain dish. Such a system has the advantage of lower mass, lower volume, improved reliability, less stringent pointing requirements, lower cost and risk. We propose to design and build a prototype Ka-band transmit antenna with an active sub-array using 125W TWTAs. The system could be applied to a telecommunications downlink or radar transmitter used for missions such as JIMO.
NASA Technical Reports Server (NTRS)
Kato, S.
A middle and upper atmospheric radar system is described. The antenna array consists of 25 groups each of which consists of 19 crossed-Yagis with three elements; each antenna has semiconductor transmitter and receiver, called a module, and each group of 19 antennas works as an independent small radar steering its radar beam under the control of a microcomputer. Thus, the total system consists of 25 small radars of this kind, enabling one to do various sophisticated operations with the system. The system is controlled by two other computers, one for radar controlling (HP9835A) and the other for data taking and on-line analysis (VAX11/750). The computer-controlled system is simple in operation for users and reliable in observation. Very quick beam steering (as quick as in a msec) is also possible because of electronic phase-changing of each module output under control of the microcomputer which is further controlled by the radar controller.
NASA Astrophysics Data System (ADS)
Malowicki, E.
A method is presented for the determination of radar frequency radiation power densities that the PAVE PAWS radar system could produce in its air and ground environment. The effort was prompted by the concern of the people in the vicinity of OTIS AFB MA and BEALE AFB CA about the possible radar frequency radiation hazard of the PAVE PAWS radar. The method is based on the following main assumptions that: (a) the total field can be computed as the vector summation of the individual fields due to each antenna element; (b) the individual field can be calculated using distances for which the field point is in the far field of the antenna element. An RFR computer program was coded for the RADC HE 6180 digital computer and exercised to calculate the radiation levels in the air and ground space for the present baseline and the possible Six DB and 10 DB growth systems of the PAVE PAWS radar system at OTIS AFB MA. The average radiation levels due to the surveillance fence were computed for three regions: in the air space in front of the radar, at the radar hazard fence at OTIS AFB MA and at representative ground points in the OTIS AFB vicinity. It was concluded that the radar frequency radiation of PAVE PAWS does not present a hazard to personnel provided there is no entry to the air hazard zone or to the area within the hazard fence. The method developed offers a cost effective way to determine radiation levels from a phased array radar especially in the near field and transition regions.
Bird-aircraft strike avoidance radar
Ning Huansheng; Chen Weishi; Mao Xia; Li Jing
Avian radar system has been developed for bird-aircraft strike hazard avoidance. Two representative systems, which are countrywide and airport-based avian radar systems, are surveyed to summarize the state-of-the-art in this research field. Avian radar experimental system built by Beihang University is introduced in detail, including system architecture, performance analysis, and processing algorithm for bird target detection and tracking. This radar
Rendezvous radar for orbital vehicles
John W. Locke; Larry D. Casey
In this paper some of the factors which relate to the system design of rendezvous radars are discussed and the system design and the capabilities of the OMV Rendezvous Radar System (RRS) are described. The potential for transferring manufacturing technologies and methods which have been developed for high-volume-production commercial and military hardware systems into the relatively low volume world of
NASA Astrophysics Data System (ADS)
Warwick, G.
Progress in civil and military radar units since the invention of radar in 1935 is summarized, noting the trend to multipurpose units. The earliest systems functioned at 10 cm, then 3 cm after development of a cavity magnetron to provide power for shorter wavelengths. Military needs are driving improvements in three-dimensional scanning capabilities, Primarily to locate aircraft in the presence of ground clutter and sea surface scattering. Autonomous, separate transmitter and receiver units are being tested. Lengthening ground-based radar wavelengths to tens of meters will permit over-the-horizon sensing with backscattering, ionospheric bounce, or induction of a potential in the sea surface as the possible techniques. Mode S monopulse radars will permit transponder queries between small and large aircraft. Finally, pulse Doppler SAR systems may afford terrain recognition with no corroborating data except an expert systems data base.
NASA Astrophysics Data System (ADS)
This ITOP outlines the test methods used in evaluating the performance and characteristics of general types of radar transmitters to include single or variable frequency transmitters. The test methods serve as a guide in determining the overall efficiency of such equipment as a function of their design and their recorded performance. This ITOP is limited to methods for measuring the performance of the radar transmitter under test as a major component. Some performance aspects of the transmitter can be tested only when configured as part of a total radar system.
Imaging radar techniques for remote sensing applications.
NASA Technical Reports Server (NTRS)
Zelenka, J. S.
The basic concepts of fine-resolution, imaging radar systems are reviewed. Both side-looking and hologram (downward-looking) radars are described and compared. Several examples of microwave imagery obtained with these two types of systems are shown.
Leopold J. Cantafio
The design and operation of space-based radar (SBR) systems are discussed in chapters contributed by leading experts. An overview of current and planned SBRs is presented, and particular attention is given to SBR-platform orbits, the ionospheric environment and its effects on SBR detection, space-based SARs, bistatic SBRs, rendezvous radars, radar altimeters for space vehicles, scatterometers and other modest-resolution systems, and
The NASA radar entomology program at Wallops Flight Center
NASA Technical Reports Server (NTRS)
Vaughn, C. R.
NASA contribution to radar entomology is presented. Wallops Flight Center is described in terms of its radar systems. Radar tracking of birds and insects was recorded from helicopters for airspeed and vertical speed.
The GeoSAR program: Development of a commercially viable 3-D radar terrain mapping system
Carlisle, R.G. [Decision-Science Applications, Inc., Arlington, VA (United States); Davis, M. [Defense Advanced Research Projects Agency, Arlington, VA (United States)
GeoSAR is joint development between the Defense Advanced Research Project Agency (DARPA) and the California Department of Conservation (CA DOC) to determine the technical and economic viability of an airborne interferometric and foliage penetration synthetic aperture radar for mapping terrain and man made objects in geographical areas obscured by foliage, urban buildings, and other concealments. The two core technology elements of this program are Interferometric Synthetic Aperture Radar (IFSAR) and Foliage Penetration Radar (FOPEN). These technologies have been developed by NASA and ARPA, principally for defense applications.
Solid-state radar transmitters
NASA Astrophysics Data System (ADS)
Ostroff, E. D.; Borkowski, M.; Thomas, H.; Curtis, J.
The technology and design procedures for introducing transistors into radio transmitters are discussed. The design characteristics of solid-state radar transmitters are described, with emphasis given to power amplifier/modules and devices for summing the output power in space or in an output combiner. Some design issues related to power supplies, pulse waveform amplitude regulation; reliability; and cost; and also considered. Some examples of successful solid-state radar systems are described, including the AN/TPS-59 radar, the AN/SPS-40 system, and the Pave/PAWS phased array radar. Black and white photographs of the different systems are provided.
A Real-Time Nowcast/Forecast System for Radar Electrojet Clutter Driven by Global Assimilative Models of the Ionosphere
NASA Astrophysics Data System (ADS)
Carrano, C. S.; Alcala, C. M.; Liang, P.; Groves, K. M.; Donatelli, D. E.; Daniell, R. E.
The Space-Based Radar Ionospheric Effects Simulation (SBR-IES) tool was developed to predict the degrading effects of the ionosphere on the performance of space-based radar systems. This presentation focuses on the technique used by the SBR-IES to predict radar electrojet clutter. The term electrojet clutter refers to backscatter from electron density irregularities that develop in response to unstable (two-stream) current systems in the auroral and equatorial electrojets. The two-stream instability is a dominant mechanism for the generation of electrojet clutter for radars operating in and above the VHF frequency band. The effects of these irregularities on the performance of ground- and space-based radars are discussed. The ionospheric clutter predictions are made using the approach developed for the Comprehensive E-Region Auroral Clutter (CERAC) model by SRI International and Rome Laboratory. The threshold velocity required for the generation of ionospheric irregularities by the two-stream instability is computed using nonlinear plasma wave theory. The streaming velocity, or the relative velocity between the electrons and ions, is calculated based on the ExB drift. When the streaming velocity exceeds the threshold, the clutter strength is estimated using an empirical relationship involving the radar frequency, electron density, magnetic aspect angle, and flow angle. A uniformly distributed layer of scattering irregularities is assumed. The ionospheric clutter predictions provided by the initial version of the SBR-IES tool were based on a climatological, or average, description of ionospheric conditions at the time of observation, driven by Kp, Ap, and the 10.7 cm solar flux. This approach, while having the advantage of requiring only a few geophysical input parameters to run, is limited by the use of overly simplified (smoothed) climatological models for the electric field, as well as electron, ion, and neutral densities and temperatures within the E-region. This deficiency is particularly pronounced during geomagnetic storm activity, when the ionospheric response deviates most from climatological behavior. The latest version of the SBR-IES tool can accept, as input, real-time specifications of the ionosphere provided by global assimilative models (e.g. PRISM or GAIM) that are currently or soon to be in operational use at AFWA. Forecasts of radar clutter can be generated using forecasts of the ionospheric state provided by the Ionospheric Forecast Model (IFM), for example. In the near future we plan to include the high resolution specification of the electric field provided by the real-time incoherent scatter radars of the Super Dual Auroral Radar Network (SuperDARN). It is expected that the use of data assimilative models to provide the background ionospheric densities, temperatures, and electric field will lead to substantially more accurate and high resolution predictions of radar electrojet clutter. Moreover, these improvements can be made without sacrificing real-time impact assessment requirements.
NASA Astrophysics Data System (ADS)
Brookner, E.
The operating principles, technology, and applications of phased-array radars are reviewed and illustrated with diagrams and photographs. Consideration is given to the antenna elements, circuitry for time delays, phase shifters, pulse coding and compression, and hybrid radars combining phased arrays with lenses to alter the beam characteristics. The capabilities and typical hardware of phased arrays are shown using the US military systems COBRA DANE and PAVE PAWS as examples.
Terminal Doppler weather radar
M. Michelson; W. W. Shrader; J. G. Wieler
The terminal Doppler weather radar (TDWR) system, now under development, will provide automatic detection of microbursts and low-level wind shear. This paper discusses the TDWR performance parameters and describes its structural elements, including the antenna subsystem, the transmitter, the receiver\\/exciter, the digital signal processor, and the radar product generator\\/remote monitoring subsystem. Attention is also given to the processes of the
Synthetic aperture radar for a crop information system: A multipolarization and multitemporal approach
NASA Astrophysics Data System (ADS)
Ban, Yifang
Acquisition of timely information is a critical requirement for successful management of an agricultural monitoring system. Crop identification and crop-area estimation can be done fairly successfully using satellite sensors operating in the visible and near-infrared (VIR) regions of the spectrum. However, data collection can be unreliable due to problems of cloud cover at critical stages of the growing season. The all-weather capability of synthetic aperture radar (SAR) imagery acquired from satellites provides data over large areas whenever crop information is required. At the same time, SAR is sensitive to surface roughness and should be able to provide surface information such as tillage-system characteristics. With the launch of ERS-1, the first long-duration SAR system became available. The analysis of airborne multipolarization SAR data, multitemporal ERS-1 SAR data, and their combinations with VIR data, is necessary for the development of image-analysis methodologies that can be applied to RADARSAT data for extracting agricultural crop information. The overall objective of this research is to evaluate multipolarization airborne SAR data, multitemporal ERS-1 SAR data, and combinations of ERS-1 SAR and satellite VIR data for crop classification using non-conventional algorithms. The study area is situated in Norwich Township, an agricultural area in Oxford County, southern Ontario, Canada. It has been selected as one of the few representative agricultural 'supersites' across Canada at which the relationships between radar data and agriculture are being studied. The major field crops are corn, soybeans, winter wheat, oats, barley, alfalfa, hay, and pasture. Using airborne C-HH and C-HV SAR data, it was found that approaches using contextual information, texture information and per-field classification for improving agricultural crop classification proved to be effective, especially the per-field classification method. Results show that three of the four best per-field classification accuracies (\\ K=0.91) are achieved using combinations of C-HH and C-VV SAR data. This confirms the strong potential of multipolarization data for crop classification. The synergistic effects of multitemporal ERS-1 SAR and Landsat TM data are evaluated for crop classification using an artificial neural network (ANN) approach. The results show that the per-field approach using a feed-forward ANN significantly improves the overall classification accuracy of both single-date and multitemporal SAR data. Using the combination of TM3,4,5 and Aug. 5 SAR data, the best per-field ANN classification of 96.8% was achieved. It represents an 8.5% improvement over a single TM3,4,5 classification alone. Using multitemporal ERS-1 SAR data acquired during the 1992 and 1993 growing seasons, the radar backscatter characteristics of crops and their underlying soils are analyzed. The SAR temporal backscatter profiles were generated for each crop type and the earliest times of the year for differentiation of individual crop types were determined. Orbital (incidence-angle) effects were also observed on all crops. The average difference between the two orbits was about 3 dB. Thus attention should be given to the local incidence-angle effects when using ERS-1 SAR data, especially when comparing fields from different scenes or different areas within the same scene. Finally, early- and mid-season multitemporal SAR data for crop classification using sequential-masking techniques are evaluated, based on the temporal backscatter profiles. It was found that all crops studied could be identified by July 21.
A Tower-based Prototype VHF/UHF Radar for Subsurface Sensing: System Description and Data Inversion Results
NASA Technical Reports Server (NTRS)
Moghaddam, Mahta; Pierce, Leland; Tabatabaeenejad, Alireza; Rodriguez, Ernesto
Knowledge of subsurface characteristics such as permittivity variations and layering structure could provide a breakthrough in many terrestrial and planetary science disciplines. For Earth science, knowledge of subsurface and subcanopy soil moisture layers can enable the estimation of vertical flow in the soil column linking surface hydrologic processes with that in the subsurface. For planetary science, determining the existence of subsurface water and ice is regarded as one of the most critical information needs for the study of the origins of the solar system. The subsurface in general can be described as several near-parallel layers with rough interfaces. Each homogenous rough layer can be defined by its average thickness, permittivity, and rms interface roughness assuming a known surface spectral distribution. As the number and depth of layers increase, the number of measurements needed to invert for the layer unknowns also increases, and deeper penetration capability would be required. To nondestructively calculate the characteristics of the rough layers, a multifrequency polarimetric radar backscattering approach can be used. One such system is that we have developed for data prototyping of the Microwave Observatory of Subcanopy and Subsurface (MOSS) mission concept. A tower-mounted radar makes backscattering measurements at VHF, UHF, and L-band frequencies. The radar is a pulsed CW system, which uses the same wideband antenna to transmit and receive the signals at all three frequencies. To focus the beam at various incidence angles within the beamwidth of the antenna, the tower is moved vertically and measurements made at each position. The signals are coherently summed to achieve focusing and image formation in the subsurface. This requires an estimate of wave velocity profiles. To solve the inverse scattering problem for subsurface velocity profile simultaneously with radar focusing, we use an iterative technique based on a forward numerical solution of the layered rough surface problem. The layers are each defined in terms of a small number of unknown distributions as given above. An a priori estimate of the solution is first assumed, based on which the forward problem is solved for the backscattered measurements. This is compared with the measured data and using iterative techniques an update to the solution for the unknowns is calculated. The process continues until convergence is achieved. Numerical results will be shown using actual radar data acquired with the MOSS tower radar system in Arizona in Fall 2003, and compared with in-situ measurements.
UK airborne AESA radar research
Stephen Moore
This paper reviews current UK airborne active electronically scanned array (AESA) designs, discusses current trends towards higher digitisation and multi-function aperture concepts, and details the key future challenges that this technology faces. Specifically the paper discusses applications to fast-jets. Key requirements are for higher levels of digitisation to provide the performance required in ECCM, STAP, GMTI and ESM modes. Building
Lunar Pole Illumination and Communications Maps Computed from Goldstone Solar System Radar Elevation Data
NASA Astrophysics Data System (ADS)
Bryant, S.
The Goldstone Solar System Radar (GSSR) group at JPL produced a digital elevation model (DEM) of the lunar south pole using data obtained in 2006. This new DEM has 40-m horizontal resolution and about 5-m relative vertical accuracy. This article explains how this DEM was used to evaluate average solar illumination and Earth visibility near the lunar south pole. The elevation data were converted into local terrain horizon masks for the area within 100 km of the lunar south pole. These topocentric horizon masks were converted into selenographic latitude and longitude coordinates, then compared to regions bounding the maximum Sun and Earth motions relative to the Moon. Estimates of Earth visibility were computed by integrating the area of the region bounding the Earth's motion that was below the horizon mask. Solar illumination and other metrics were computed similarly. Proposed lunar south pole base sites are examined in detail, with the best site showing multiyear averages of solar power availability of 92 percent and direct-to-Earth (DTE) communication availability of 51 percent. Results are compared with a theoretical model and with actual Sun and Earth visibility averaged over the years 2009 to 2028. Peaks near the lunar south pole with continuous DTE communications are also presented. Results for the lunar north pole were computed using the GSSR DEM of the lunar north pole produced in 1997. The article also explores using a heliostat to reduce the photovoltaic power system mass and complexity.
Short Wavelength Technology and the Potential for Distributed Networks of Short-Range Radar Systems
Cruz-Pol, Sandra L.
of the troposphere. Data collected by these sensors serve as critical inputs to weather-related decision making, tracking, and predicting algorithms) that diagnose weather conditions in real-time and re-steer radar beams
Digital Map Products from the Cassini RADAR in the NASA Planetary Data System
NASA Astrophysics Data System (ADS)
Kirk, R. L.; Becker, T. L.; Garcia, P.; Barrett, J. M.; Stiles, B. W.; Legall, A.; Janssen, M. A.; Wye, L.; Zebker, H. A.; Cassini RADAR Science Team
A new set of Titan maps, made from Cassini RADAR prime mission data, will be delivered early in 2010. Consistent presentation of diverse data sets in simple projections with extensive indexing should greatly facilitate comparative Titan research.
The S�o Lu�s 30 MHz coherent scatter ionospheric radar: System description and initial results
Eurico R. de Paula; David L. Hysell
A new 30 MHz coherent scatter ionospheric radar has been operating at the equatorial station at S�o Lu�s (2.33�S, 44�W, dip latitude 1.3�S), Brazil, since December 2000. This VHF radar has a peak power of only 8 kW but uses long coded pulses and a high PRF with coherent integration to achieve good sensitivity. Two side-by-side square antenna arrays composed
Simulated KWAJEX Convective Systems Using a 2D and 3D Cloud Resolving Model and Their Comparisons with Radar Observations
NASA Technical Reports Server (NTRS)
Shie, Chung-Lin; Tao, Wei-Kuo; Simpson, Joanne
The 1999 Kwajalein Atoll field experiment (KWAJEX), one of several major TRMM (Tropical Rainfall Measuring Mission) field experiments, has successfully obtained a wealth of information and observation data on tropical convective systems over the western Central Pacific region. In this paper, clouds and convective systems that developed during three active periods (Aug 7-12, Aug 17-21, and Aug 29-Sep 13) around Kwajalein Atoll site are simulated using both 2D and 3D Goddard Cumulus Ensemble (GCE) models. Based on numerical results, the clouds and cloud systems are generally unorganized and short lived. These features are validated by radar observations that support the model results. Both the 2D and 3D simulated rainfall amounts and their stratiform contribution as well as the heat, water vapor, and moist static energy budgets are examined for the three convective episodes. Rainfall amounts are quantitatively similar between the two simulations, but the stratiform contribution is considerably larger in the 2D simulation. Regardless of dimension, fo all three cases, the large-scale forcing and net condensation are the two major physical processes that account for the evolution of the budgets with surface latent heat flux and net radiation solar and long-wave radiation)being secondary processes. Quantitative budget differences between 2D and 3D as well as between various episodes will be detailed.Morover, simulated radar signatures and Q1/Q2 fields from the three simulations are compared to each other and with radar and sounding observations.
Polarimetric synthetic aperture radar image unsupervised classification method based on artificial immune system
NASA Astrophysics Data System (ADS)
Jie, Yu; Gang, Wang; Teng, Zhu; Xiaojuan, Li; Qin, Yan
An unsupervised classification method based on the H/? classifier and artificial immune system (AIS) is proposed to overcome the inefficiencies that arise when traditional classification methods deal with polarimetric synthetic aperture radar (PolSAR) data having large numbers of overlapping pixels and excess polarimetric information. The method is composed of two steps. First, Cloude-Pottier decomposition is used to obtain the entropy H and the scattering angle ?. The classification result based on the H/? plane is used to initialize the AIS algorithm. Second, to obtain accurate results, the AIS clonal selection algorithm is used to perform an iterative calculation. As a self-organizing, self-recognizing, and self-optimizing algorithm, the AIS is able to obtain a global optimal solution and better classification results by making use of both the scattering mechanism of ground features and polarimetric scattering characteristics. The effectiveness and feasibility of this method are demonstrated by experiments using a NASA-JPL PolSAR image and a high-resolution PolSAR image of Lingshui autonomous county in Hainan Province.
Use of the X-Band Radar to Support the Detection of In-Flight Icing Hazards by the NASA Icing Remote Sensing System
NASA Technical Reports Server (NTRS)
Serke, David J.; Politovich, Marcia K.; Reehorst, Andrew L.; Gaydos, Andrew
The Alliance Icing Research Study-II (AIRS-II) field program was conducted near Montreal, Canada during the winter of 2003. The NASA Icing Remote Detection System (NIRSS) was deployed to detect in-flight icing hazards and consisted of a vertically pointing multichannel radiometer, a ceilometer and an x-band cloud radar. The radiometer was used to derive atmospheric temperature soundings and integrated liquid water, while the ceilometer and radar were used only to define cloud boundaries. The purpose of this study is to show that the radar reflectivity profiles from AIRS-II case studies could be used to provide a qualitative icing hazard.
Frequency diversity in multistatic radars
Byung Wook Jung; R aviraj S. Adve; Joohwan Chun
This paper presents the model and analysis of a frequency-diverse radar system. Multistatic radar systems provide an inherent spatial diversity by processing signals from different platforms which view a potential target from different aspect angles. By using different frequencies at each platform, an additional diversity gain can be obtained on top of the advantages of spatial diversity. Here, since platforms
Radar techniques to study subsurfaces and interiors of the solar system objects.
NASA Astrophysics Data System (ADS)
Kofman, W.
The radar techniques are widely used in the planetary exploration to map the surfaces. The observations from Earth or from spacecrafts were developed during the last decades. However, the idea to use this technique to study the subsurface started to develop during the last 10-15 years. The ability of the radio waves to penetrate the ice, permafrost and arid surface was at the origins of the development of the Ground Penetrating Radars (GPR) with a large number of the scientific work and industrial applications on Earth. The measurements from the surface can not replace the global mapping from orbiting platforms. In this presentation, on the example of MARSIS radar on the Mars Express mission measurements we evaluate the general capabilities of radar sounders for planetary exploration. The CONSERT is the experiment on board of the ROSETTA mission that will provide information about the deep interior of the comet (Kofman et al, 1998, 2007). The CONSERT instrument is an original concept of spaceborne transmission radar based on the propagation throughout the nucleus while the classical radars are based on the reflection. In this experiment, an electromagnetic signal is transmitted between the lander, located on the comet surface, and the orbiter. The transmitted signal will be measured as a function of time and as a function of the relative position of the orbiter and the lander for a number of orbits. Any signal that has propagated through the medium contains information concerning this medium. With a sufficient number of orbits one will be able to obtain many cuts of the interior of the comet and therefore to build up a tomographic image of the interior. On the CONSERT experiment example we discuss the main advantages and difficulties of the techniques using radiowaves to study the interior of asteroids and comets. The capacity of radar technique to do the tomography of the interior of the asteroids and comets is emphasized.
The application of satellite radar interferometry to the study of land subsidence over developed aquifer systems
NASA Astrophysics Data System (ADS)
Hoffmann, Joern
This dissertation investigates the application of interferometric synthetic aperture radar (InSAR) to measuring and interpreting surface displacements over developed aquifer systems. These widely observed displacements result from elastic and inelastic deformation of water-bearing material at depth due to pore-fluid pressure changes. InSAR satellite data can map surface displacements over extensive areas at millimeter precision and high spatial detail. This work uses InSAR to investigate time-dependent deformation processes in aquifer systems. InSAR-derived displacements have not previously been employed to estimate heterogeneous aquifer system parameters. Where applicable, InSAR provides a powerful tool for characterizing aquifer systems, which often are an important resource to local communities. I have used InSAR to map the recent time-varying surface displacement fields over the Las Vegas Valley, Nevada and Antelope Valley, California aquifer systems, obtaining detailed and spatially complete characterizations of the heterogeneous displacement fields. The structure of the displacement fields often reflects known or previously unknown subsurface structure such as faults or changing sediment thicknesses, emphasizing the value of InSAR in delineating subsurface units. A comparison of displacements measured with different viewing geometries indicated primarily vertical surface displacements in Antelope Valley. This has been a widely used, albeit hitherto generally untested assumption in basin-scale studies of land subsidence. The observed displacement fields reflect effects of both seasonal fluctuations and long-term stress trends in the aquifer system. Combining InSAR observations with other information on these stress variations I estimated heterogeneous storage parameters for the aquifer systems. In Las Vegas Valley, the estimated aquifer system elastic skeletal storage coefficients range from 4.2 � 10-4 to 3.4 � 10-3. In Antelope Valley, since the drainage of thick low-conductivity units is delayed with respect to aquifer drawdowns, subsidence continues for decades after the hydraulic head declines have ceased. Here I estimated inelastic skeletal storage coefficients up to 0.09 and compaction time constants for interbed compaction ranging from 3 to 285 years in a three-dimensional groundwater flow and subsidence (MODFLOW) model. Numerical simulations show that the accuracy and frequency of InSAR observations are sufficient to constrain storage parameter estimations. However, unreliable drawdown estimates in regional aquifer systems severely limit these analyses.
High-power transmitters for radar applications
Meppalli K. Shandas
High-power transmitters are one of the critical elements in a radar system. The radar waveform needs to be amplified without distortion to the desired output power level by the high-power transmitter. In addition to affecting the overall performance of the radar system, the design of the transmitter affects many other factors, such as size, weight, power consumption, operating cost, reliability
Nehorai, Arye
Chapter 10 APPLICATION OF SENSOR SCHEDULING CONCEPTS TO RADAR William Moran University of Melbourne time illustrating the ideas on sensor schedul- ing in a specific context: that of a radar system. A typical pulse radar system operates by illuminating a scene with a short pulse of electromagnetic energy
AESA upgrade option for Eurofighter Captor radar
M. Barclay; U. Pietzschmann; G. Gonzalez; P. Tellini
The Euroradar consortium has successfully developed and demonstrated an AESA technology upgrade for the Eurofighter Typhoon Captor radar. This technology demonstrator, designated CAESAR, enables E-scan capability to be fully exploited by the existing Captor radar, while retaining all features and capabilities of the original system. Advanced waveforms, designed and optimised for electronically scanned radar systems, have been evaluated in recent
Characterization of Mesoscale Convective Systems by Means of Composite Radar Reflectivity Data
NASA Technical Reports Server (NTRS)
Geerts, Bart
A mesoscale convective system (MCS) is broadly defined as a cloud and precipitation system of mesoscale dimensions (often too large for most aircraft to circumnavigate) with deep-convective activity concentrated in at least part of the MCS, or present during part of its evolution. A large areal fraction of MCSs is stratiform in nature, yet estimates from MCSs over the Great Plains, the Southeast, and tropical waters indicate that at least half of the precipitation is of convective origin. The presence of localized convection is important, because within convective towers cloud particles and hydrometeors are carried upward towards the cloud top. Ice crystals then move over more stratiform regions, either laterally, or through in situ settling over decaying and spreading convection. These ice crystals then grow to precipitation-size particles in mid- to upper tropospheric mesoscale updrafts. The convective portion of a MCS is often a more or less continuous line of thunderstorms, and may be either short-lived or long-lived. Geerts (1997) presents a preliminary climatology of MCSs in the southeastern USA, using just one year of composite digital radar reflectivity data. In this study MCSs are identified and characterized by means of visual inspection of animated images. A total of 398 MCSs were identified. In the warm season MCSs were found to be about twice as frequent as in the cold season. The average lifetime and maximum length of MCSs are 9 hours, and 350 km, respectively, but some MCSs are much larger and more persistent. In the summer months small and short-lived MCSs are relatively more common, whereas in winter larger and longer-lived systems occur more frequently. MCSs occur more commonly in the afternoon, in phase with thunderstorm activity, but the amplitude of the diurnal cycle is small compared to that of observed thunderstorms. It is estimated that in the Southeast more than half of all precipitation and severe weather results from MCSs.
A prototype of radar-drone system for measuring the surface flow velocity at river sites and discharge estimation
NASA Astrophysics Data System (ADS)
Moramarco, Tommaso; Alimenti, Federico; Zucco, Graziano; Barbetta, Silvia; Tarpanelli, Angelica; Brocca, Luca; Mezzanotte, Paolo; Rosselli, Luca; Orecchini, Giulia; Virili, Marco; Valigi, Paolo; Ciarfuglia, Thomas; Pagnottelli, Stefano
Discharge estimation at a river site depends on local hydraulic conditions identified by recording water levels. In fact, stage monitoring is straightforward and relatively inexpensive compared with the cost necessary to carry out flow velocity measurements which are, however, limited to low flows and constrained by the accessibility of the site. In this context the mean flow velocity is hard to estimate for high flow, affecting de-facto the reliability of discharge assessment for extreme events. On the other hand, the surface flow velocity can be easily monitored by using radar sensors allowing to achieve a good estimate of discharge by exploiting the entropy theory applied to rivers hydraulic (Chiu,1987). Recently, a growing interest towards the use of Unmanned Aerial Vehicle (UVA), henceforth drone, for topographic applications is observed and considering their capability drones may be of a considerable interest for the hydrological monitoring and in particular for streamflow measurements. With this aim, for the first time, a miniaturized Doppler radar sensor, operating at 24 GHz, will be mounted on a drone to measure the surface flow velocity in rivers. The sensor is constituted by a single-board circuit (i.e. is a fully planar circuits - no waveguides) with the antenna on one side and the front-end electronic on the other side (Alimenti et al., 2007). The antenna has a half-power beam width of less than 10 degrees in the elevation plane and a gain of 13 dBi. The radar is equipped with a monolithic oscillator and transmits a power of about 4 mW at 24 GHz. The sensor is mounted with an inclination of 45 degrees with respect to the drone flying plane and such an angle is considered in recovering the surface speed of the water. The drone is a quadricopter that has more than 30 min, flying time before recharging the battery. Furthermore its flying plan can be scheduled with a suitable software and is executed thanks to the on-board sensors (GPS, accelerometers, altimeter, camera) and artificial intelligence. Finally it has more than 0.3 kg payload that can be used for further instruments. With respect to the conventional approach, that uses radar sensors on fixed locations, the system prototype composed of drone and Doppler radar is more flexible and would allow carrying out velocity measurements obtaining the whole transverse surface velocity profile during high flow and for inaccessible river sites as well. This information represents the boundary condition of the entropy model (Moramarco et al. 2004) able to turn the surface velocity in discharge, known the geometry of the river site. Nowadays the prototype is being implemented and the Doppler radar sensor is tested in a static way, i.e. the flow velocity accuracy is determined in real-case situations by comparing the sensor output with that of conventional instruments. The first flying test is planned shortly in some river sites of Tiber River in central Italy and based on the surface velocity survey the capability of the radar-drone prototype will be tested and the benefit in discharge assessment by using the entropy model will be verified. Alimenti, F., Placentino, F., Battistini, A., Tasselli, G., Bernardini, W., Mezzanotte, P., Rascio, D., Palazzari, V., Leone, S., Scarponi, A., Porzi, N., Comez, M. and Roselli, L. (2007). "A Low-Cost 24GHz Doppler Radar Sensor for Traffic Monitoring Implemented in Standard Discrete-Component Technology". Proceedings of the 2007 European Radar Conference (EuRAD 2007), pp. 162-165, Munich, Germany, 10-12 October 2007 Chiu, C. L. (1987). "Entropy and probability concepts in hydraulics". J. Hydr. Engrg., ASCE, 113(5), 583-600. Moramarco, T., Saltalippi, C., Singh, V.P.(2004). "Estimation of mean velocity in natural channels based on Chiu's velocity distribution equation", Journal of Hydrologic Engineering, 9 (1), pp. 42-50
Case study of Mesoscale Convective Systems over Hungary on 29 June 2006 with satellite, radar and lightning data
NASA Astrophysics Data System (ADS)
Putsay, M�ria; Szeny�n, Ildik�; Simon, Andr�
On 29 June 2006 two Mesoscale Convective Systems (MCS) crossed Hungary causing severe weather, heavy precipitation, hail and strong wind. The first MCS transformed to a Mesoscale Convective Vortex (MCV) in its dissipating phase. The case was analyzed using different remote sensing devices: satellites, radars and a lightning detection system. Visible images from the METEOSAT-8 satellite were used to discriminate thin and thick parts of the anvil and to identify the overshooting tops. Structures like cold rings and cold-U/V shapes detected from infrared imagery indicate possible penetration of the storm top into the tropopause or lower stratosphere. The near and medium infrared solar channels (and some thermal IR channel differences) provide information on cloud top microphysics. The spatial distribution of the cloud top ice crystal size was investigated with the use of the so called "convective storms" composite imagery obtained from brightness temperature and reflectivity differences of water vapor, infrared and short-wave channels. The MODIS band 1 (0.645 �m) image of the TERRA satellite shows gravity wave generation at the top of the thunderstorm cloud, which could be connected to the strength and pulsations of the updraft. Satellite images were overlaid with radar reflectivities, which are characterized by an asymmetric bow echo. It is concluded that composites of satellite, radar and lightning data help to assess relative locations of main up- and downdrafts and important features of the severe storm.
Removing interfering clutter associated with radar pulses that an airborne radar receives from a radar transponder
Ormesher, Richard C. (Albuquerque, NM); Axline, Robert M. (Albuquerque, NM)
Interfering clutter in radar pulses received by an airborne radar system from a radar transponder can be suppressed by developing a representation of the incoming echo-voltage time-series that permits the clutter associated with predetermined parts of the time-series to be estimated. These estimates can be used to estimate and suppress the clutter associated with other parts of the time-series.
A new approach to increase the two-dimensional detection probability of CSI algorithm for WAS-GMTI mode
NASA Astrophysics Data System (ADS)
Yan, H.; Zheng, M. J.; Zhu, D. Y.; Wang, H. T.; Chang, W. S.
When using clutter suppression interferometry (CSI) algorithm to perform signal processing in a three-channel wide-area surveillance radar system, the primary concern is to effectively suppress the ground clutter. However, a portion of moving target's energy is also lost in the process of channel cancellation, which is often neglected in conventional applications. In this paper, we firstly investigate the two-dimensional (radial velocity dimension and squint angle dimension) residual amplitude of moving targets after channel cancellation with CSI algorithm. Then, a new approach is proposed to increase the two-dimensional detection probability of moving targets by reserving the maximum value of the three channel cancellation results in non-uniformly spaced channel system. Besides, theoretical expression of the false alarm probability with the proposed approach is derived in the paper. Compared with the conventional approaches in uniformly spaced channel system, simulation results validate the effectiveness of the proposed approach. To our knowledge, it is the first time that the two-dimensional detection probability of CSI algorithm is studied.
Research on the Configuration of Network Radar Based on Detectable Power and Detector's SNR
Liu Yueping; Jiang Qiuxi; Guo Hangxing
Network Radar realizes the integration of radar and radar countermeasure, thus it is a new direction for the development of radar and radar countermeasure system. This essay first introduces the existing concept and research results of the configuration of Network Radar and then it probes into how to configure the transmitters and receivers based on the method of detectable power
Australian Weather Watch Radar Home Page
NSDL National Science Digital Library
The Commonwealth Bureau of Meteorology's Weather Watch Radar website provides up-to-date radar images of the locations of rain in Australia in relation to local features such as coast lines. The newly developed Loops provide four consecutive radar images so that users can view how the weather has been changing in the last forty to fifty minutes. The website provides radar images of past cyclone events as well as updates on severe weather throughout Australia. Those interested in radar systems can discover how the weather radars work and how to interpret the maps. [RME
Cognitive processing for nonlinear radar
NASA Astrophysics Data System (ADS)
Martone, Anthony; Ranney, Kenneth; Hedden, Abigail; Mazzaro, Gregory; McNamara, David
An increasingly cluttered electromagnetic environment (EME) is a growing problem for radar systems. This problem is becoming critical as the available frequency spectrum shrinks due to growing wireless communication device usage and changing regulations. A possible solution to these problems is cognitive radar, where the cognitive radar learns from the environment and intelligently modifies the transmit waveform. In this paper, a cognitive nonlinear radar processing framework is introduced where the main components of this framework consist of spectrum sensing processing, target detection and classification, and decision making. The emphasis of this paper is to introduce a spectrum sensing processing technique that identifies a transmit-receive frequency pair for nonlinear radar. It will be shown that the proposed technique successfully identifies a transmit-receive frequency pair for nonlinear radar from data collected from the EME.
Analyzing the connectivity potential of landscape geomorphic systems: a radar remote sensing and GIS approach, Estufa Canyon, Texas, USA�
Ibrahim, ElSayed Ali Hermas
Potential of Landscape Geomorphic Systems: A Radar Remote Sensing and GIS Approach, Estufa Canyon, Texas, USA. (August 2005) ElSayed Ali Hermas Ibrahim, B.S., Mansoura University; M.S., Mansoura University Chair of Advisory Committee: Dr. John R... the slope magnitude (S) and the connectivity potential (C p ) is suggested as: C p ? S (1) Thus, C p = K 1 * S (2) where: C p is the connectivity potential of the geomorphic system, S is the mean slope of the geomorphic system...
Motion parameter estimation of multiple ground moving targets in multi-static passive radar systems
NASA Astrophysics Data System (ADS)
Subedi, Saurav; Zhang, Yimin D.; Amin, Moeness G.; Himed, Braham
Multi-static passive radar (MPR) systems typically use narrowband signals and operate under weak signal conditions, making them difficult to reliably estimate motion parameters of ground moving targets. On the other hand, the availability of multiple spatially separated illuminators of opportunity provides a means to achieve multi-static diversity and overall signal enhancement. In this paper, we consider the problem of estimating motion parameters, including velocity and acceleration, of multiple closely located ground moving targets in a typical MPR platform with focus on weak signal conditions, where traditional time-frequency analysis-based methods become unreliable or infeasible. The underlying problem is reformulated as a sparse signal reconstruction problem in a discretized parameter search space. While the different bistatic links have distinct Doppler signatures, they share the same set of motion parameters of the ground moving targets. Therefore, such motion parameters act as a common sparse support to enable the exploitation of group sparsity-based methods for robust motion parameter estimation. This provides a means of combining signal energy from all available illuminators of opportunity and, thereby, obtaining a reliable estimation even when each individual signal is weak. Because the maximum likelihood (ML) estimation of motion parameters involves a multi-dimensional search and its performance is sensitive to target position errors, we also propose a technique that decouples the target motion parameters, yielding a two-step process that sequentially estimates the acceleration and velocity vectors with a reduced dimensionality of the parameter search space. We compare the performance of the sequential method against the ML estimation with the consideration of imperfect knowledge of the initial target positions. The Cram�r-Rao bound (CRB) of the underlying parameter estimation problem is derived for a general multiple-target scenario in an MPR system. Simulation results are provided to compare the performance of the sparse signal reconstruction-based methods against the traditional time-frequency-based methods as well as the CRB.
Global mapping strategies for a synthetic aperture radar system in orbit about Venus
NASA Technical Reports Server (NTRS)
Kerridge, S. J.
An analysis of the global mapping of Venus using a synthetic aperture radar (SAR) is presented. The geometry of the side-looking radar, the narrow swath width, and the slow rotation of Venus combine to constrain the methods required to produce such a map within the primary mapping mission of 121.5 days. Parametric studies indicate that multiple strategies can satisfy the requirements of the mission with reasonable assumptions for the total recording capacity, the downlink data rate, and the operating time of the SAR on each revolution.
NASA Astrophysics Data System (ADS)
Hall, Roger B.
A radar sector blanker comprises in analog-to-digital converter and a sector controller unit. The analog-to-digital converter receives the analog synchro voltages describing the positioning of a radar antenna and changes these voltages into binary-coded decimal (BCD) information. The sector controller unit comprises a portable housing, a controller system, and a power supply. The controller system includes an OFF comparator circuit, an ON comparator circuit, an S-R latch, and a solid-state switch. Each comparator circuit comprises three cascaded transistor-transistor logic (TTL) integrated chips. The power supply gives a direct-current voltage to the solid-state switch and the TTL chips. The sector blanker blocks transmission for a predetermined rotational region or sector of a radar system.
Maritime surveillance with synthetic aperture radar (SAR) and automatic identification system (AIS) onboard a microsatellite constellation
NASA Astrophysics Data System (ADS)
Peterson, E. H.; Zee, R. E.; Fotopoulos, G.
New developments in small spacecraft capabilities will soon enable formation-flying constellations of small satellites, performing cooperative distributed remote sensing at a fraction of the cost of traditional large spacecraft missions. As part of ongoing research into applications of formation-flight technology, recent work has developed a mission concept based on combining synthetic aperture radar (SAR) with automatic identification system (AIS) data. Two or more microsatellites would trail a large SAR transmitter in orbit, each carrying a SAR receiver antenna and one carrying an AIS antenna. Spaceborne AIS can receive and decode AIS data from a large area, but accurate decoding is limited in high traffic areas, and the technology relies on voluntary vessel compliance. Furthermore, vessel detection amidst speckle in SAR imagery can be challenging. In this constellation, AIS broadcasts of position and velocity are received and decoded, and used in combination with SAR observations to form a more complete picture of maritime traffic and identify potentially non-cooperative vessels. Due to the limited transmit power and ground station downlink time of the microsatellite platform, data will be processed onboard the spacecraft. Herein we present the onboard data processing portion of the mission concept, including methods for automated SAR image registration, vessel detection, and fusion with AIS data. Georeferencing in combination with a spatial frequency domain method is used for image registration. Wavelet-based speckle reduction facilitates vessel detection using a standard CFAR algorithm, while leaving sufficient detail for registration of the filtered and compressed imagery. Moving targets appear displaced from their actual position in SAR imagery, depending on their velocity and the image acquisition geometry; multiple SAR images acquired from different locations are used to determine the actual positions of these targets. Finally, a probabilistic inference model combines the SAR target data with transmitted AIS data, taking into account nearest-neighbor position matches and uncertainty models of each observation.
OFDM waveforms for multistatic radars
Y. Paichard
In this paper, the benefits of OFDM waveforms are analyzed for multistatic radar systems, where several radar stations cooperate in the same frequency band. The signal is coded over a 2D pattern, in the time and the frequency domains, using orthogonal Golay complementary sets derived from Reed-Muller codes. Binary data are also encoded in the signal. The obtained ambiguity and
NASA Astrophysics Data System (ADS)
Cantafio, Leopold J.
The design and operation of space-based radar (SBR) systems are discussed in chapters contributed by leading experts. An overview of current and planned SBRs is presented, and particular attention is given to SBR-platform orbits, the ionospheric environment and its effects on SBR detection, space-based SARs, bistatic SBRs, rendezvous radars, radar altimeters for space vehicles, scatterometers and other modest-resolution systems, and thermal control for SBRs. Also considered are the radar cross sections of satellites and other space targets, SBR clutter and interference, space antenna technology, onboard radar-signal processors, space power systems, and SBR structures. Diagrams, drawings, graphs, maps, and tables of numerical data are provided.
46 CFR 169.726 - Radar reflector.
Code of Federal Regulations, 2011 CFR
...2011-10-01 2011-10-01 false Radar reflector. 169.726 Section 169...Systems, and Equipment � 169.726 Radar reflector. Each nonmetallic vessel less than 90 feet in length must exhibit a radar reflector of suitable size and design...
Code of Federal Regulations, 2010 CFR
...2010-10-01 2010-10-01 false Radar. 167.40-40 Section 167.40-40...Equipment Requirements � 167.40-40 Radar. All mechanically propelled vessels...coastwise service must be fitted with a marine radar system for surface navigation....
Code of Federal Regulations, 2011 CFR
...2011-10-01 2011-10-01 false Radars. 121.404 Section 121.404 Shipping... Navigation Equipment � 121.404 Radars. (a) Except as allowed by paragraph...Commission (FCC) type accepted general marine radar system for surface navigation with...
Code of Federal Regulations, 2010 CFR
...2010-10-01 2010-10-01 false Radar. 108.717 Section 108.717 Shipping...Miscellaneous Equipment � 108.717 Radar. Each self-propelled unit of 1...coastwise service must have� (a) A marine radar system for surface navigation; and...
Code of Federal Regulations, 2011 CFR
...2011-10-01 2011-10-01 false Radars. 184.404 Section 184.404 Shipping... Navigation Equipment � 184.404 Radars. (a) A vessel must be fitted with...Commission (FCC) type accepted general marine radar system for surface navigation with...
Code of Federal Regulations, 2010 CFR
...2010-10-01 2010-10-01 false Radars. 184.404 Section 184.404 Shipping... Navigation Equipment � 184.404 Radars. (a) A vessel must be fitted with...Commission (FCC) type accepted general marine radar system for surface navigation with...
Code of Federal Regulations, 2011 CFR
...2011-10-01 2011-10-01 false Radar. 167.40-40 Section 167.40-40...Equipment Requirements � 167.40-40 Radar. All mechanically propelled vessels...coastwise service must be fitted with a marine radar system for surface navigation....
Code of Federal Regulations, 2010 CFR
...2010-10-01 2010-10-01 false Radars. 121.404 Section 121.404 Shipping... Navigation Equipment � 121.404 Radars. (a) Except as allowed by paragraph...Commission (FCC) type accepted general marine radar system for surface navigation with...
Code of Federal Regulations, 2011 CFR
...2011-10-01 2011-10-01 false Radar. 108.717 Section 108.717 Shipping...Miscellaneous Equipment � 108.717 Radar. Each self-propelled unit of 1...coastwise service must have� (a) A marine radar system for surface navigation; and...
46 CFR 169.726 - Radar reflector.
Code of Federal Regulations, 2010 CFR
...2010-10-01 2010-10-01 false Radar reflector. 169.726 Section 169...Systems, and Equipment � 169.726 Radar reflector. Each nonmetallic vessel less than 90 feet in length must exhibit a radar reflector of suitable size and design...
The nature of bistatic and multistatic radar
Wang Beide
Bistatic and multistatic radar has some properties which are completely different from current monostatic radar. Some special properties that are closely related to tactical applications are derived. Through overall analysis, we believe that this will become one of the most important military radar systems
Fifty years of bistatic and multistatic radar
J. I. Glaser
The article begins with a review of bistatic and multistatic radars, including the simultaneous introduction of radar technology in several countries during the 1930s and the various areas of technology development pursued by those countries. Technical descriptions are presented of nine different experimental systems. The article continues with a discussion of the potential military and nonmilitary advantages of bistatic radars
Noise modulated multistatic surveillance radar concept
Vesa-Jukka Salminen; Timo Lensu; Pekka Eskelinen; Simo Mertanen
Noise modulated surveillance radars have many desirable properties. However, practical problems with signal processing and system design have inhibited noise modulated radars to become common. Fast improving signal processing will probably change this in future. We have studied what kind of noise modulated radar might be realistic in 15 years. Advantages are good LPI, good ECCM, good ARM avoidance, good
Dual-use air traffic control radar
Lewis Buckler
During the past seven years the Federal Aviation Administration has had a research program called the Terminal Area Surveillance System (TASS) to develop the next generation airport surveillance radar. At present the FAA has two radars for aircraft and weather surveillance at the major airports. One of these radars, the ASR-9, is for aircraft surveillance and rain intensity. The other,
AESA upgrade option for Eurofighter Captor Radar
M. Barclay; U. Pietzschmann; G. Gonzalez; P. Tellini
The Euroradar Consortium has successfully developed and demonstrated an Active Electronically Scanned Array (AESA) technology upgrade for the Eurofighter Typhoon Captor Radar. This technology demonstrator, designated Captor Active Electronically Scanned Array Radar (CAESAR), enables E-scan capability to be fully exploited by the existing Captor radar, while retaining all features and capabilities of the original system. Advanced waveforms, designed and optimized
76 FR 35176 - Operation of Radar Systems in the 76-77 GHz Band
Federal Register 2010, 2011, 2012, 2013, 2014
...power level and because both would use antennas with narrow beamwidths, thus reducing...be within the main lobe of the receive antenna of the other. In a worst case scenario...radars in the 76-77 GHz band (e.g., antenna height, operational frequency or...
Upgraded Doppler Rayleigh Lidar and Comparisonswith Stratospheric Radar: 1: Observations Following Initial System Modifications
Cho, John Y. N.
run. METHODOLOGY Changes to the Doppler Rayleigh lidar include a refitted laser transmitter and hysteresis present with the pressure scanning instrument. The two color seed laser will give an absoluteUpgraded Doppler Rayleigh Lidar and Comparisonswith Stratospheric Radar: 1: Observations Following
Radar techniques to study subsurfaces and interiors of the solar system objects
W. Kofman
The radar techniques are widely used in the planetary exploration to map the surfaces. The observations from Earth or from spacecrafts were developed during the last decades. However, the idea to use this technique to study the subsurface started to develop during the last 10-15 years. The ability of the radio waves to penetrate the ice, permafrost and arid surface
A Virtual Antenna Beamforming (VAB) Approach for Radar Systems by Using Orthogonal Coding Waveforms
Hai Deng; Braham Himed
An innovative approach is introduced to form virtual transmitting and receiving radar antenna beams simultaneously by transmitting orthogonal coding waveforms from the antenna elements and digitally processing of their echoes at the receiver. Multiple virtual transmitting-receiving beams can be formed simultaneously by employing an equal number of beamforming filters without increasing transmitting power or antenna gain or resolution loss. The
On the range resolution of point targets with FMCW radar systems
Reinhard Hammel
The spectral analysis of the low pass filtered echo signals of a stationary point target was carried out starting with the precise position of the transmit signal of a Frequency Modulated Continuous-Wave (FMCW) radar operated with sawtooth modulation and assuming a signal transit time which is short compared with the modulation period. It can be stated that the minimum detectable
Radar reflection off extensive air showers
Stasielak, J; Bertaina, M; Bl�mer, J; Chiavassa, A; Engel, R; Haungs, A; Huege, T; Kampert, K -H; Klages, H; Kleifges, M; Kr�mer, O; Ludwig, M; Mathys, S; Neunteufel, P; Pekala, J; Rautenberg, J; Riegel, M; Roth, M; Salamida, F; Schieler, H; �m�da, R; Unger, M; Weber, M; Werner, F; Wilczy?ski, H; Wochele, J
We investigate the possibility of detecting extensive air showers by the radar technique. Considering a bistatic radar system and different shower geometries, we simulate reflection of radio waves off the static plasma produced by the shower in the air. Using the Thomson cross-section for radio wave reflection, we obtain the time evolution of the signal received by the antennas. The frequency upshift of the radar echo and the power received are studied to verify the feasibility of the radar detection technique.
NASA Technical Reports Server (NTRS)
Flom, T.
Development of laser systems to acquire and track targets in applications such as the rendezvous and docking of two spacecraft. A scan technique is described whereby a narrow laser beam is simultaneously scanned with an equally narrow receiver field-of-view without the aid of mechanical gimbals. Equations are developed in order to examine the maximum acquisition and tracking rates, and the maximum target range for a scanning laser radar system. A recently built prototype of a small, lightweight, low-power-consuming scanning laser radar is described.
Development of a GPS-aided motion measurement, pointing, and stabilization system for a Synthetic Aperture Radar. [Global Positioning System (GPS)
Fellerhoff, J.R.; Kohler, S.M.
An advanced Synthetic Aperture Radar Motion Compensation System has been developed by Sandia National Laboratories (SNL). The system includes a miniaturized high accuracy ring laser gyro inertial measurement unit, a three axis gimbal pointing and stabilization assembly, a differential Global Positioning System (GPS) navigation aiding system, and a pilot guidance system. The system provides several improvements over previous SNL motion compensation systems and is capable of antenna stabilization to less than 0.01 degrees RMS and absolute position measurement to less than 5.0 meters RMS. These accuracies have been demonstrated in recent flight testing aboard a DHC-6-300 Twin Otter'' aircraft.
Investigation of laser radar systems based on mid-infrared semiconductor lasers
NASA Astrophysics Data System (ADS)
Rybaltowski, Adam
This dissertation deals with the possibility of utilizing mid-infrared semiconductor lasers in systems of optical remote sensing with range resolution, called laser radar or lidar. The main subject investigated in this dissertation is two-fold: firstly, an analysis of the signal-to-noise ratio (SNR) and related maximum sensing range calculations in this type of lidar based on available system components, and---secondly---improvements in the Random-Modulation Continuous-Wave (RM-CW) lidar technique to better utilize available mid-infrared semiconductor lasers. As far as the SNR analysis is concerned, an appropriate framework has been constructed to analyze post-demodulation noise in mid-infrared direct-detection RM-CW lidar. It is based on a generalization of the Wiener-Khintchine theorem; noise is assumed to be additive, stationary, and have an arbitrary power spectrum. This is in contrast to the SNR analysis in the literature on this subject, which is inadequate for mid-infrared RM-CW lidar as it only considers Poissonian fluctuations of the number of detected photons. In addition to regular SNR analysis, the framework derived in this dissertation allows treatment of singularities such as demodulation with an unbalanced sequence in 1/f noise. To calculate maximum lidar sensing range, the following detection limits have been considered: signal shot noise, background blackbody radiation shot noise based on the Background-Limited Photodetection (BLIP) detectivity limit, and minimum-size detector noise given by diffraction-limited focusing. The latter is found to be of greatest practical interest. Furthermore, a lidar figure of merit has been introduced, and all quantities related to lidar performance and its detection limits have been presented graphically. Since pseudo-random sequences discussed in the literature have been found highly non-optimal for most applications of RM-CW lidar, a framework for the construction of new pseudo-random sequences of desired correlation properties has been introduced. As an example, a new pseudo-random sequence has been devised, and shown to have significantly improved and nearly-ideal signal and noise properties. Also, a novel scheme of continuous-wave Differential Absorption Lidar (DIAL) using only one transmitter and one receiver has been proposed, which combined with its minimal baseband signal modulation requirements should lead to greatly simplified and improved practical chemical-sensing lidar. The results of this dissertation prove the feasibility of mid-infrared semiconductor laser based lidar in many important applications, and provide an analytical framework to advance their practical realization. The most immediate applications of this work are expected in remote detection of noxious airborne biological and chemical substances, and in automobile collision avoidance systems.
Rendezvous radar for orbital vehicles
NASA Astrophysics Data System (ADS)
Locke, John W.; Casey, Larry D.
In this paper some of the factors which relate to the system design of rendezvous radars are discussed and the system design and the capabilities of the OMV Rendezvous Radar System (RRS) are described. The potential for transferring manufacturing technologies and methods which have been developed for high-volume-production commercial and military hardware systems into the relatively low volume world of hi-rel electronics hardware for space is discussed.
Measurement of the horizontal velocity of wind perturbations in the middle atmosphere by spaced MF radar systems
NASA Technical Reports Server (NTRS)
Meek, C. E.; Manson, A. H.; Smith, M. J.
Two remote receiving sites have been set up at a distance of approx 40 km from the main MF radar system. This allows measurement of upper atmosphere winds from 60-120 km (3 km resolution) at the corners of an approximately equilateral triangle of side approx 20 km. Some preliminary data are compared through cross correlation and cross spectral analysis in an attempt to determine the horizontal velocity of wind perturbations and/or the horizontal wavelength and phase velocity of gravity waves.
NASA Astrophysics Data System (ADS)
Tompkins, R. D.
The World Administrative Radio Conference of 1979 (WARC-79) will have a significant effect on the design, development, and operation of radar systems. This paper discusses the changes in the Table of Frequency Allocations which will affect radar and notes some of the problems which will be faced by the radar community in maintaining system performance requirements. An urgent need is shown for expanding the participation by radar developers in the affairs of the International Radio Consultative Committee (CCIR). This participation is essential to create and maintain a technical basis for radar which will define spectrum needs, examine spectrum usage, and describe techniques for efficient spectrum utilization within the International Telecommunications Union (ITU).
System and method for measuring ocean surface currents at locations remote from land masses using synthetic aperture radar
NASA Technical Reports Server (NTRS)
Young, Lawrence E. (inventor)
A system for measuring ocean surface currents from an airborne platform is disclosed. A radar system having two spaced antennas wherein one antenna is driven and return signals from the ocean surface are detected by both antennas is employed to get raw ocean current data which are saved for later processing. There are a pair of global positioning system (GPS) systems including a first antenna carried by the platform at a first location and a second antenna carried by the platform at a second location displaced from the first antenna for determining the position of the antennas from signals from orbiting GPS navigational satellites. Data are also saved for later processing. The saved data are subsequently processed by a ground-based computer system to determine the position, orientation, and velocity of the platform as well as to derive measurements of currents on the ocean surface.
Modular RADAR: An Immune System Inspired Search and Response Strategy for Distributed Systems
Soumya Banerjee; Melanie E. Moses
The Natural Immune System (NIS) is a distributed system that solves\\u000achallenging search and response problems while operating under constraints\\u000aimposed by physical space and resource availability. Remarkably, NIS search and\\u000aresponse times do not scale appreciably with the physical size of the animal in\\u000awhich its search is conducted. Many distributed systems are engineered to solve\\u000aanalogous problems, and
A short-term predictive system for surface currents from a rapidly deployed coastal HF radar network
NASA Astrophysics Data System (ADS)
Barrick, Donald; Fernandez, Vicente; Ferrer, Maria I.; Whelan, Chad; Breivik, �yvind
In order to address the need for surface trajectory forecasts following deployment of coastal HF radar systems during emergency-response situations (e.g., search and rescue, oil spill), a short-term predictive system (STPS) based on only a few hours data background is presented. First, open-modal analysis (OMA) coefficients are fitted to 1-D surface currents from all available radar stations at each time interval. OMA has the effect of applying a spatial low-pass filter to the data, fills gaps, and can extend coverage to areas where radial vectors are available from a single radar only. Then, a set of temporal modes is fitted to the time series of OMA coefficients, typically over a short 12-h trailing period. These modes include tidal and inertial harmonics, as well as constant and linear trends. This temporal model is the STPS basis for producing up to a 12-h current vector forecast from which a trajectory forecast can be derived. We show results of this method applied to data gathered during the September 2010 rapid-response demonstration in northern Norway. Forecasted coefficients, currents, and trajectories are compared with the same measured quantities, and statistics of skill are assessed employing 16 24-h data sets. Forecasted and measured kinetic variances of the OMA coefficients typically agreed to within 10-15%. In one case where errors were larger, strong wind changes are suspected and examined as the cause. Sudden wind variability is not included properly within the STPS attack we presently employ and will be a subject for future improvement.
Modelling the performance of USV manoeuvring and target tracking: an approach using frequency modulated continuous wave radar rotary system.
Onunka, Chiemela; Nnadozie, Remigius Chidozie
The performance of frequency modulated continuous wave (FMCW) radar in tracking targets is presented and analysed. Obstacle detection, target tracking and radar target tracking performance models are developed and were used to investigate and to propose ways of improving the autonomous motion of unmanned surface vehicle (USV). Possible factors affecting the performance of FMCW radar in tracking targets are discussed and analysed. PMID:23853743
Regional and Diurnal Variability of the Vertical Structure of Precipitation Systems in Africa Based on Spaceborne Radar Data
Geerts, Bart
on Spaceborne Radar Data BART GEERTS AND TEFERI DEJENE Department of Atmospheric Science, University of Wyoming on an instantaneous basis, but also cumulatively (Kummerow et al. 2000). Spaceborne radar data can be used also Rainfall Measuring Mission (TRMM) 2A25 radar reflectivity profiles and derived surface rain rates are used
The RADAR Test Methodology: Evaluating a MultiTask Machine Learning System with Humans in the Loop
Aaron Steinfeld; Rachael Bennett; Kyle Cunningham; Matt Lahut; Pablo-Alejandro Quinones; Django Wexler; Dan Siewiorek; Paul Cohen; Julie Fitzgerald; Othar Hansson; Jordan Hayes; Mike Pool; Mark Drummond
The RADAR project involves a collection of machine learning research thrusts that are integrated into a cognitive personal assistant. Progress is examined with a test developed to measure the impact of learning when used by a human user. Three conditions (conventional tools, Radar without learning, and Radar with learning) are evaluated in a large-scale, between- subjects study. This paper describes
A Method to Merge WSR-88D Data with ARM SGP Millimeter Cloud Radar Data by Studying Deep Convective Systems
Dong, Xiquan
A Method to Merge WSR-88D Data with ARM SGP Millimeter Cloud Radar Data by Studying Deep Convective A decade of collocated Atmospheric Radiation Measurement Program (ARM) 35-GHz Millimeter Cloud Radar (MMCR) and Weather Surveillance Radar-1988 Doppler (WSR-88D) data over the ARM Southern Great Plains (SGP) site have
An airport wind shear detection and warning system using Doppler radar: A feasibility study
NASA Technical Reports Server (NTRS)
Mccarthy, J.; Blick, E. F.; Elmore, K. L.
A feasibility study was conducted to determine whether ground based Doppler radar could measure the wind along the path of an approaching aircraft with sufficient accuracy to predict aircraft performance. Forty-three PAR approaches were conducted, with 16 examined in detail. In each, Doppler derived longitudinal winds were compared to aircraft measured winds; in approximately 75 percent of the cases, the Doppler and aircraft winds were in acceptable agreement. In the remaining cases, errors may have been due to a lack of Doppler resolution, a lack of co-location of the two sampling volumes, the presence of eddy or vortex like disturbances within the pulse volume, or the presence of point targets in antenna side lobes. It was further concluded that shrouding techniques would have reduced the side lobe problem. A ground based Doppler radar operating in the optically clear air, provides the appropriate longitudinal winds along an aircraft's intended flight path.
Instantaneous Radar Polarimetry with Multiple Dually-polarized Antennas
Pezeshki, Ali
1 Instantaneous Radar Polarimetry with Multiple Dually-polarized Antennas A. R. Calderbank,1 S. D radar systems are capable of simultaneously transmitting and receiving in two orthogonal polarizations. Instantaneous radar polarimetry exploits both polarization modes of a dually-polarized radar transmitter
Multi-static Synthetic Aperture Radar Image Formation
Yazici, Birsen
Multi-static Synthetic Aperture Radar Image Formation V. P. Krishnan Department of Electrical a multi-static synthetic aperture radar (SAR) imaging scenario where a swarm of airborne antennas, some-static radar are less effective against distributed radar systems [3], [4]. Finally, multi-static measurements
When Target Motion Matters: Doppler Coverage in Radar Sensor Networks
Reisslein, Martin
that are not of interest as well as objects of interest (e.g., targets). The detection performance of radar systems-covered if, regardless of its direction of motion, there exists some radar in the network whose signal- to for arbitrarily deployed radars. Then we design an algorithm for deriving the minimum radar density required
Status and trends in AESA-based radar
W. Holpp
Radar technology, predominantly in the area of defence applications, is in a continuous process of extending its present capabilities. Especially Active Electronically Scanned Array (AESA) radars, with their unprecedented degree of operational flexibility, are currently about to revolutionise the performance of air- and spaceborne, naval and ground radars. The current status of AESA radar and the trends in system and
The gust-front detection and wind-shift algorithms for the Terminal Doppler Weather Radar system
NASA Technical Reports Server (NTRS)
Hermes, Laurie G.; Witt, Arthur; Smith, Steven D.; Klingle-Wilson, Diana; Morris, Dale; Stumpf, Gregory J.; Eilts, Michael D.
The Federal Aviation Administration's (FAA) Terminal Doppler Weather Radar (TDWR) system was primarily designed to address the operational needs of pilots in the avoidance of low-altitude wind shears upon takeoff and landing at airports. One of the primary methods of wind-shear detection for the TDWR system is the gust-front detection algorithm. The algorithm is designed to detect gust fronts that produce a wind-shear hazard and/or sustained wind shifts. It serves the hazard warning function by providing an estimate of the wind-speed gain for aircraft penetrating the gust front. The gust-front detection and wind-shift algorithms together serve a planning function by providing forecasted gust-front locations and estimates of the horizontal wind vector behind the front, respectively. This information is used by air traffic managers to determine arrival and departure runway configurations and aircraft movements to minimize the impact of wind shifts on airport capacity. This paper describes the gust-front detection and wind-shift algorithms to be fielded in the initial TDWR systems. Results of a quantitative performance evaluation using Doppler radar data collected during TDWR operational demonstrations at the Denver, Kansas City, and Orlando airports are presented. The algorithms were found to be operationally useful by the FAA airport controllers and supervisors.
Dynamic Experiment Design Regularization Approach to Adaptive Imaging with Array Radar/SAR Sensor Systems
Shkvarko, Yuriy; Tuxpan, Jos�; Santos, Stewart
We consider a problem of high-resolution array radar/SAR imaging formalized in terms of a nonlinear ill-posed inverse problem of nonparametric estimation of the power spatial spectrum pattern (SSP) of the random wavefield scattered from a remotely sensed scene observed through a kernel signal formation operator and contaminated with random Gaussian noise. First, the Sobolev-type solution space is constructed to specify the class of consistent kernel SSP estimators with the reproducing kernel structures adapted to the metrics in such the solution space. Next, the �model-free� variational analysis (VA)-based image enhancement approach and the �model-based� descriptive experiment design (DEED) regularization paradigm are unified into a new dynamic experiment design (DYED) regularization framework. Application of the proposed DYED framework to the adaptive array radar/SAR imaging problem leads to a class of two-level (DEED-VA) regularized SSP reconstruction techniques that aggregate the kernel adaptive anisotropic windowing with the projections onto convex sets to enforce the consistency and robustness of the overall iterative SSP estimators. We also show how the proposed DYED regularization method may be considered as a generalization of the MVDR, APES and other high-resolution nonparametric adaptive radar sensing techniques. A family of the DYED-related algorithms is constructed and their effectiveness is finally illustrated via numerical simulations. PMID:22163859
Dynamic experiment design regularization approach to adaptive imaging with array radar/SAR sensor systems.
Shkvarko, Yuriy; Tuxpan, Jos�; Santos, Stewart
We consider a problem of high-resolution array radar/SAR imaging formalized in terms of a nonlinear ill-posed inverse problem of nonparametric estimation of the power spatial spectrum pattern (SSP) of the random wavefield scattered from a remotely sensed scene observed through a kernel signal formation operator and contaminated with random Gaussian noise. First, the Sobolev-type solution space is constructed to specify the class of consistent kernel SSP estimators with the reproducing kernel structures adapted to the metrics in such the solution space. Next, the "model-free" variational analysis (VA)-based image enhancement approach and the "model-based" descriptive experiment design (DEED) regularization paradigm are unified into a new dynamic experiment design (DYED) regularization framework. Application of the proposed DYED framework to the adaptive array radar/SAR imaging problem leads to a class of two-level (DEED-VA) regularized SSP reconstruction techniques that aggregate the kernel adaptive anisotropic windowing with the projections onto convex sets to enforce the consistency and robustness of the overall iterative SSP estimators. We also show how the proposed DYED regularization method may be considered as a generalization of the MVDR, APES and other high-resolution nonparametric adaptive radar sensing techniques. A family of the DYED-related algorithms is constructed and their effectiveness is finally illustrated via numerical simulations. PMID:22163859
The DEFENSE (debris Flows triggEred by storms - nowcasting system): An early warning system for torrential processes by radar storm tracking using a Geographic Information System (GIS)
NASA Astrophysics Data System (ADS)
Tiranti, Davide; Cremonini, Roberto; Marco, Federica; Gaeta, Armando Riccardo; Barbero, Secondo
Debris flows, responsible for economic losses and occasionally casualties in the alpine region, are mainly triggered by heavy rains characterized by hourly peaks of varying intensity, depending on the features of the basin under consideration. By integrating a recent classification of alpine basins with the radar storm tracking method, an innovative early warning system called DEFENSE (DEbris Flows triggEred by storms - Nowcasting SystEm) was developed using a Geographical Information System (GIS). Alpine catchments were classified into three main classes based on the weathering capacity of the bedrock into clay or clay-like minerals, the amount of which, in unconsolidated material, directly influences the debris flow rheology, and thus the sedimentary processes, the alluvial fan architecture, as well as the triggering frequency and seasonal occurrence probability of debris flows. Storms were identified and tracked by processing weather radar observations; subsequently, rainfall intensities and storm severity were estimated over each classified basin. Due to rainfall threshold values determined for each basin class, based on statistical analysis of historical records, an automatic corresponding warning could be issued to municipalities.
International Radar Conference, Arlington, VA, May 6-9, 1985, Record and Supplement
NASA Astrophysics Data System (ADS)
The topics discussed in this volume include advanced antennas and transmitters, targets and environments, signal processing, specialized radars adn techniques, synthetic aperture radar, and radar automation, as well as some novel radar system designs. Papers are presented on an efficient three-dimensional radar design, monitoring and calibration of active phased arrays, the solid state transmitter for the AN/SPS-40 radar system, and the superresolution application in tracking radar. Consideration is given to Doppler estimation accuracy of linear FM waveforms, a bistatic pulse-Doppler intruder detection radar, detectability of low flying targets in real terrain using a diffraction model, a technique for adaptive polarization filtering in radars, and the effects of polarization on the marine radar detection of icebergs. In addition, strategies for radar frequency selection, low probability of intercept radar, synthetic aperture imaging airborne radar, and optical techniques for signal distribution and control in phased array radars are discussed.
NASA Technical Reports Server (NTRS)
Leberl, F.; Fuchs, H.; Ford, J. P.
A set of ten side-looking radar images of a mining area in Arizona that were aquired over a period of 14 yr are studied to demonstrate the photogrammetric differential-rectification technique applied to radar images and to examine changes that occurred in the area over time. Five of the images are rectified by using ground control points and a digital height model taken from a map. Residual coordinate errors in ground control are reduced from several hundred meters in all cases to + or - 19 to 70 m. The contents of the radar images are compared with a Landsat image and with aerial photographs. Effects of radar system parameters on radar images are briefly reviewed.
Weather and radar interactions
J. P. Booth
This paper discusses the effects of weather on radar system performance. This discussion were based on computer simulations and climatological data. The relationships between frequency and range were explored as they interact with the weather. This effort is being conducted in the RF Technology Division of the Applied Sensors, Guidance, and Electronics Directorate, US Army Aviation and Missile Research, Development,
Multistatic radar detection - Synthesis and comparison of optimum and suboptimum receivers
Ernesto Conte; E. Daddio; Alfonso Farina; Maurizio Longo
Multistatic radar systems can be regarded as radars having one or more transmitting antennas, which are associated with one or more receiving antennas. The antennas are placed in separate locations. For some time monostatic radars have been predominantly used. However, in the case of military radars, techniques have to be found to make the radar systems less vulnerable to attack
The Weather Radar Toolkit, National Oceanic and Atmospheric Administration (NOAA) National Climatic Data Center's support of interoperability and the Global Earth Observation System of Systems (GEOSS)
NASA Astrophysics Data System (ADS)
Ansari, S.; Del Greco, S.
In February 2005, 61 countries around the World agreed on a 10 year plan to work towards building open systems for sharing geospatial data and services across different platforms worldwide. This system is known as the Global Earth Observation System of Systems (GEOSS). The objective of GEOSS focuses on easy access to environmental data and interoperability across different systems allowing participating countries to measure the "pulse" of the planet in an effort to advance society. In support of GEOSS goals, NOAA's National Climatic Data Center (NCDC) has developed radar visualization and data exporter tools in an open systems environment. The NCDC Weather Radar Toolkit (WRT) loads Weather Surveillance Radar 1988 Doppler (WSR-88D) volume scan (S-band) data, known as Level-II, and derived products, known as Level-III, into an Open Geospatial Consortium (OGC) compliant environment. The application is written entirely in Java and will run on any Java- supported platform including Windows, Macintosh and Linux/Unix. The application is launched via Java Web Start and runs on the client machine while accessing these data locally or remotely from the NCDC archive, NOAA FTP server or any URL or THREDDS Data Server. The WRT allows the data to be manipulated to create custom mosaics, composites and precipitation estimates. The WRT Viewer provides tools for custom data overlays, Web Map Service backgrounds, animations and basic filtering. The export of images and movies is provided in multiple formats. The WRT Data Exporter allows for data export in both vector polygon (Shapefile, Well-Known Text) and raster (GeoTIFF, ESRI Grid, VTK, NetCDF, GrADS) formats. By decoding the various Radar formats into the NetCDF Common Data Model, the exported NetCDF data becomes interoperable with existing software packages including THREDDS Data Server and the Integrated Data Viewer (IDV). The NCDC recently partnered with NOAA's National Severe Storms Lab (NSSL) to decode Sigmet C-band Doppler radar data providing the NCDC Viewer/Data Exporter the functionality to read C-Band. This also supports a bilateral agreement between the United States and Canada for data sharing and to support interoperability with the US WSR-88D and Environment Canada radar networks. In addition, the NCDC partnered with the University of Oklahoma to develop decoders to read a test bed of distributed X- band radars that are funded through the Collaborative Adaptive Sensing of the Atmosphere (CASA) project. The NCDC is also archiving the National Mosaic and Next Generation QPE (Q2) products from NSSL, which provide products such as three-dimensional reflectivity, composite reflectivity and precipitation estimates at a 1 km resolution. These three sources of Radar data are also supported in the WRT.
Advantages to Geoscience and Disaster Response from the QuakeSim Implementation of Interferometric Radar Maps in a GIS Database System.
Radar Maps in a GIS Database System. Jay Parker (1), Andrea Donnellan (1), Margaret Glasscoe (1 Maps in GIS System Abstract: High-resolution maps of earth surface deformation, which are becoming, but primarily as bulky downloads. Selection through browsers and initial exploratory analysis have been tedious
Adaptiv hardware innen radar og radarapplikasjoner, Forsvarets forskningsinstitutt, Kjeller Forsvarets forskningsinstitutt (FFI) har mer enn 30 rs erfaring med forskningsarbeider innen radar
Sahay, Sundeep
Adaptiv hardware innen radar og radarapplikasjoner, Forsvarets forskningsinstitutt, Kjeller Forsvarets forskningsinstitutt (FFI) har mer enn 30 �rs erfaring med forskningsarbeider innen radar og radarapplikasjoner. Dette omhandler b�de passive systemer som brukes for � kartlegge radar scenen, kalt
L-band radar scattering from grass
NASA Technical Reports Server (NTRS)
Chauhan, N.; O'Neill, P.; Le Vine, D.; Lang, R.; Khadr, N.
A radar system based on a network analyzer has been developed to study the backscatter from vegetation. The radar is operated at L-band. Radar measurements of a grass field were made in 1991. The radar returns from the grass were measured at three incidence angles. Ground truth and canopy parameters such as blade and stem dimensions, moisture content of the grass and the soil, and blade and stem density, were measured. These parameters are used in a distorted Born approximation model to compute the backscatter coefficients from the grass layer. The model results are compared with the radar data.
Bistatic radar meteorological satellite
NASA Technical Reports Server (NTRS)
Nathanson, F. E.
A technique is discussed that employs a radar transmitter with a moderate size antenna placed in a geosynchronous orbit with either a 0 degree or a low inclination orbit. The reflected signals from the precipitation are then received either on a single beam from a satellite having a beamwidth of about 6 degrees or preferably with a beam that scans the U.S. in a raster pattern with about 0.9 degrees beamwidth. While it would seem that a bistatic system with the transmitter at synchronous altitude and the receivers near the surface would not be a very efficient way of designing a radar system, it is somewhat surprising that the required power and antenna sizes are not that great. Two factors make the meteorological application somewhat more attractive than the bistatic detection of point targets. First, the bistatic reflections of radar signals from precipitation are to a large extent omnidirectional, and while raindrops are spheriods rather than spheres, the relationship of the reflectivity of the rain to rainfall rate can be easily derived. The second reason is that the rain echo signal level is independent of range from a receive only radar, and if the bistatic system works at all, it will work at long ranges.
Fabrication of Radar Absorbing Shells Made of Hybrid Composites and Evaluation of Radar Cross Section
Woo-Kyun Jung; Sung-Hoon Ahn; Bierng-Chearl Ahn
** , Seoung-Bae Park ** and Myung-Shik Won *** ABSTRACT The avoidance of enemy's radar detection is very important issue in the modern electronic weapon system. Researchers have been studied to minimize reflected signals of radar. In this research, two types of radar absorbing structure (RAS), \\
Using doppler radar images to estimate aircraft navigational heading error
Doerry, Armin W. (Albuquerque, NM); Jordan, Jay D. (Albuquerque, NM); Kim, Theodore J. (Albuquerque, NM)
A yaw angle error of a motion measurement system carried on an aircraft for navigation is estimated from Doppler radar images captured using the aircraft. At least two radar pulses aimed at respectively different physical locations in a targeted area are transmitted from a radar antenna carried on the aircraft. At least two Doppler radar images that respectively correspond to the at least two transmitted radar pulses are produced. These images are used to produce an estimate of the yaw angle error.
Contaminants in a soil-plant-lemming food chain system at a military radar site in the Canadian Arctic
Dushenko, W.T.; Bright, D.A.; Grundy, S.L.; Reimer, K.J. [Royal Roads Military College, Victoria, British Columbia (Canada). Environmental Sciences Group
Environmental assessment and impact studies have been conducted at Distant Early Warning (DEW) Line and other radar sites across the Canadian Arctic and Labrador, as well as Arctic background locations since 1989. Some of the major contaminants found in soils and plants in the vicinity of the stations include PCBs and inorganic elements such as lead, copper and zinc. The impact of these contaminants at higher levels of the food chain were examined using a soil-plant-lemming system in a sewage outfall (containing high soil concentrations of contaminants) and background areas at a radar site located at Cambridge Bay, NWT. Concentrations of PCBs in tissue samples from the sewage outfall were all significantly larger than background values with averages, in some cases, differing by an order of magnitude or more. Although the average PCB concentration declines from soils (average 1,600 ppb) to plants (average 9.3 ppb) in the outfall, plant-herbivore food chain biomagnification is indicated by a 6.5 fold increase in PCB concentration between whole lemming tissues (average 61 ppb) and plants. Levels in liver tissue were double this value (123 ppb) being comparable to values reported for predators of this species. The implications of these levels are discussed in terms of ecosystem toxicity using congener specific analysis.
Using X-band Weather Radar Measurements to Monitor the Integrity of Digital Elevation Models for Synthetic Vision Systems
NASA Technical Reports Server (NTRS)
Young, Steve; UijtdeHaag, Maarten; Sayre, Jonathon
Synthetic Vision Systems (SVS) provide pilots with displays of stored geo-spatial data representing terrain, obstacles, and cultural features. As comprehensive validation is impractical, these databases typically have no quantifiable level of integrity. Further, updates to the databases may not be provided as changes occur. These issues limit the certification level and constrain the operational context of SVS for civil aviation. Previous work demonstrated the feasibility of using a realtime monitor to bound the integrity of Digital Elevation Models (DEMs) by using radar altimeter measurements during flight. This paper describes an extension of this concept to include X-band Weather Radar (WxR) measurements. This enables the monitor to detect additional classes of DEM errors and to reduce the exposure time associated with integrity threats. Feature extraction techniques are used along with a statistical assessment of similarity measures between the sensed and stored features that are detected. Recent flight-testing in the area around the Juneau, Alaska Airport (JNU) has resulted in a comprehensive set of sensor data that is being used to assess the feasibility of the proposed monitor technology. Initial results of this assessment are presented.
RADAR PRINCIPLES I Introduction
Sato, Toru
) bands. Antenna size of weather radarsis a few to about ten metersin diameter, but an} atmospheric radar atmospheric radars have antennas witli dialneter of 10- 300 in. Weather radars cover a wide horizontal areaRADAR PRINCIPLES I Introduction Radar is a general technique, willcli has a wide range
C. T. Pham; A. L. Leonard
The Shuttle Ku-band system is a dual mode system that can be operated either as a two-way communications with the ground via the Tracking and Data Relay Satellite System or as a radar system to track another spacecraft. The radar mode is used during rendezvous and proximity operations to provide range, range rate, angle, and angle rate information to the
NSDL National Science Digital Library
Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR), part of NASA's Mission to Planet Earth, is studying how our global environment is changing. From the unique vantage point of space, the radar system observes, monitors and assesses large-scale environmental processes with a focus on climate change. The spaceborne data, complemented by aircraft and ground studies, gives scientists highly detailed information that will help them distinguish natural environmental changes from those that are the result of human activity. The images are divided into nine categories for easier viewing.
Middle Atmosphere Program. Handbook for MAP. Volume 30: International School on Atmospheric Radar
NASA Technical Reports Server (NTRS)
Fukao, Shoichiro (editor)
Broad, tutorial coverage is given to the technical and scientific aspects of mesosphere stratosphere troposphere (MST) meteorological radar systems. Control issues, signal processing, atmospheric waves, the historical aspects of radar atmospheric dynamics, incoherent scatter radars, radar echoes, radar targets, and gravity waves are among the topics covered.
Electromagnetic approaches to wall characterization, wall mitigation, and antenna design for through-the-wall radar systems
NASA Astrophysics Data System (ADS)
Thajudeen, Christopher
Through-the-wall imaging (TWI) is a topic of current interest due to its wide range of public safety, law enforcement, and defense applications. Among the various available technologies such as, acoustic, thermal, and optical imaging, which can be employed to sense and image targets of interest, electromagnetic (EM) imaging, in the microwave frequency bands, is the most widely utilized technology and has been at the forefront of research in recent years. The primary objectives for any Through-the-Wall Radar Imaging (TWRI) system are to obtain a layout of the building and/or inner rooms, detect if there are targets of interest including humans or weapons, determine if there are countermeasures being employed to further obscure the contents of a building or room of interest, and finally to classify the detected targets. Unlike conventional radar scenarios, the presence of walls, made of common construction materials such as brick, drywall, plywood, cinder block, and solid concrete, adversely affects the ability of any conventional imaging technique to properly image targets enclosed within building structures as the propagation through the wall can induce shadowing effects on targets of interest which may result in image degradation, errors in target localization, and even complete target masking. For many applications of TWR systems, the wall ringing signals are strong enough to mask the returns from targets not located a sufficient distance behind the wall, beyond the distance of the wall ringing, and thus without proper wall mitigation, target detection becomes extremely difficult. The results presented in this thesis focus on the development of wall parameter estimation, and intra-wall and wall-type characterization techniques for use in both the time and frequency domains as well as analysis of these techniques under various real world scenarios such as reduced system bandwidth scenarios, various wall backing scenarios, the case of inhomogeneous walls, presence of ground reflections, and situations where they may be applied to the estimation of the parameters associated with an interior wall. It is demonstrated through extensive computer simulations and laboratory experiments that, by proper exploitation of the electromagnetic characteristics of walls, one can efficiently extract the constitutive parameters associated with unknown wall(s) as well as to characterize and image the intra-wall region. Additionally, it is possible, to a large extent, to remove the negative wall effects, such as shadowing and incorrect target localization, as well as to enhance the imaging and classification of targets behind walls. In addition to the discussion of post processing the radar data to account for wall effects, the design of antenna elements used for transmit (Tx) and receive (Rx) operations in TWR radars is also discussed but limited to antennas for mobile, handheld, or UAV TWR systems which impose design requirements such as low profiles, wide operational bands, and in most cases lend themselves to fabrication using surface printing techniques. A new class of wideband antennas, formed though the use of printed metallic paths in the form of Peano and Hilbert space-filling curves (SFC) to provide top-loading properties that miniaturize monopole antenna elements, has been developed for applications in conformal and/or low profile antennas systems, such as mobile platforms for TWRI and communication systems. Additionally, boresight gain enhancements of a stair-like antenna geometry, through the addition of parasitic self-similar patches and gate like ground plane structures, are presented.
Rain radar instrument definition
NASA Astrophysics Data System (ADS)
Vincent, Nicolas; Chenebault, J.; Suinot, Noel; Mancini, Paolo L.
As a result of a pre-phase a study, founded by ESA, this paper presents the definition of a spaceborne Rain Radar, candidate instrument for earth explorer precipitation mission. Based upon the description of user requirements for such a dedicated mission, a mission analysis defines the most suitable space segment. At system level, a parametric analysis compares pros and cons of instrument concepts associated with rain rate retrieval algorithms in order to select the most performing one. Several trade-off analysis at subsystem level leads then to the definition of the proposed design. In particular, as pulse compression is implemented in order to increase the radar sensitivity, the selected method to achieve a pulse response with a side-lobe level below--60 dB is presented. Antenna is another critical rain radar subsystem and several designs are com pared: direct radiating array, single or dual reflector illuminated by single or dual feed arrays. At least, feasibility of centralized amplification using TWTA is compared with criticality of Tx/Rx modules for distributed amplification. Mass and power budgets of the designed instrument are summarized as well as standard deviations and bias of simulated rain rate retrieval profiles. The feasibility of a compliant rain radar instrument is therefore demonstrated.
Agricultural and hydrological applications of radar
NASA Technical Reports Server (NTRS)
Ulaby, F. T.
Program objectives, covering a wide range of disciplines and activities in radar remote sensing, include radar systems development and analysis, data processing and display, and data interpretation in geology, geography and oceanography. Research was focused on the evaluation of radar remote sensing applications in hydrology and agriculture based on data acquired with the Microwave Active Spectrometer (MAS) system. The title, author(s) and abstract of each of the 62 technical reports generated under this contract are appended.
From Bursts to Back-Projection: Signal Processing Techniques for Earth and Planetary Observing Radars
NASA Technical Reports Server (NTRS)
Rosen, Paul A.
Discusses: (1) JPL Radar Overview and Historical Perspective (2) Signal Processing Needs in Earth and Planetary Radars (3) Examples of Current Systems and techniques (4) Future Perspectives in signal processing for radar missions
An Integrated Navigation System using GPS Carrier Phase for Real-Time Airborne Synthetic Aperture Radar (SAR)
Fellerhoff, J. Rick; Kim, Theodore J.; Kohler, Stewart M.
A Synthetic Aperture Radar (SAR) requires accu- rate measurement of the motion of the imaging plat- form to produce well-focused images with minimal absolute position error. The motion measurement (MoMeas) system consists of a inertial measurement unit (IMU) and a P-code GPS receiver that outputs corrected ephemeris, L1 & L2 pseudoranges, and L1 & L2 carrier phase measurements. The unknown initial carrier phase biases to the GPS satellites are modeled as states in an extended Kalman filter and the resulting integrated navigation solution has po- sition errors that change slowly with time. Position error drifts less than 1- cm/sec have been measured from the SAR imagery for various length apertures.
The development of a power spectral density processor for C and L band airborne radar scatterometer sensor systems
NASA Technical Reports Server (NTRS)
Harrison, D. A., III; Chladek, J. T.
A real-time signal processor was developed for the NASA/JSC L-and C-band airborne radar scatterometer sensor systems. The purpose of the effort was to reduce ground data processing costs. Conversion of two quadrature channels of data (like and cross polarized) was made to obtain Power Spectral Density (PSD) values. A chirp-z transform (CZT) approach was used to filter the Doppler return signal and improved high frequency and angular resolution was realized. The processors have been tested with record signals and excellent results were obtained. CZT filtering can be readily applied to scatterometers operating at other wavelengths by altering the sample frequency. The design of the hardware and software and the results of the performance tests are described in detail.
The Arecibo Observatory as an MST radar
NASA Technical Reports Server (NTRS)
Woodman, R. F.
The radars and other systems at the Arecibo Observatory were designed and built, originally, for incoherent-scatter and radio-astronomy research. More recently, important additions have been made for planetary radar and artificial RF heating of the ionosphere. Although designed and built for a different application, these systems have shown to be very powerful tools for tropospheric, stratospheric and mesospheric research. The Observatory at present has two main radars: one at 430 and the other at 2380 MHz. In addition, 50-MHz MST radar work has been done using portable transmitters brought to the Observatory for this purpose. This capability will become permanent with the recent acquisition of a transmitter at this frequency. Furthermore, control and data processing systems have been developed to use the powerful HF transmitter and antennas of the HF-heating facility as an HF bistatic radar. A brief description of the four radars available at the Observatory is presented.
Radar and sonar probing of rocks
The purpose of this paper is to summarize the research of the past sixteen years on methods of probing into solid rock. For these purposes, there are three completely different systems: radar, sonar, and nonlinear sonar. In dry salt all of the systems work. Five radar systems of different frequencies have been used to probe salt for different purposes and
Diurnal variation of precipitation by moving mesoscale systems: Radar observations in northern Thailand
NASA Astrophysics Data System (ADS)
Okumura, K.; Satomura, T.; Oki, T.; Khantiyanan, Warawut
The diurnal cycle of radar echo data observed at Om Koi, northern Thailand, during three rainy seasons (May to October, 1998, 1999 and 2000) are analyzed. From May to July when southwesterly monsoons blow over the observation area, the diurnal cycles in the leeward regions (inland of Thailand) show a phase delay that corresponds to the distance from the mountains. In October when the wind direction reverses and blows from the east or northeast, inland regions correspond to the upwind side of the mountains and do not show clear phase shifts. The regions near the coast of the Andaman Sea, which is the leeward in October, show a similar phase shift of the diurnal cycle as the inland area during May-July. The echo tracking analysis reveals that echoes, which are triggered near the mountains and moved to leeward regions, caused phase delays, which depended on the lee distance.
The NASA Polarimetric Radar (NPOL)
NASA Technical Reports Server (NTRS)
Petersen, Walter A.; Wolff, David B.
Characteristics of the NASA NPOL S-band dual-polarimetric radar are presented including its operating characteristics, field configuration, scanning capabilities and calibration approaches. Examples of precipitation science data collections conducted using various scan types, and associated products, are presented for different convective system types and previous field campaign deployments. Finally, the NASA NPOL radar location is depicted in its home base configuration within the greater Wallops Flight Facility precipitation research array supporting NASA Global Precipitation Measurement Mission ground validation.
A combined QC methodology in Ebro Delta HF radar system: real time web monitoring of diagnostic parameters and offline validation of current data
NASA Astrophysics Data System (ADS)
Lorente, Pablo; Piedracoba, Silvia; Soto-Navarro, Javier; Ruiz, Maria Isabel; Alvarez Fanjul, Enrique
Over recent years, special attention has been focused on the development of protocols for near real-time quality control (QC) of HF radar derived current measurements. However, no agreement has been worldwide achieved to date to establish a standardized QC methodology, although a number of valuable international initiatives have been launched. In this context, Puertos del Estado (PdE) aims to implement a fully operational HF radar network with four different Codar SeaSonde HF radar systems by means of: - The development of a best-practices robust protocol for data processing and QC procedures to routinely monitor sites performance under a wide variety of ocean conditions. - The execution of validation works with in-situ observations to assess the accuracy of HF radar-derived current measurements. The main goal of the present work is to show this combined methodology for the specific case of Ebro HF radar (although easily expandable to the rest of PdE radar systems), deployed to manage Ebro River deltaic area and promote the conservation of an important aquatic ecosystem exposed to a severe erosion and reshape. To this aim, a web interface has been developed to efficiently monitor in real time the evolution of several diagnostic parameters provided by the manufacturer (CODAR) and used as indicators of HF radar system health. This web, updated automatically every hour, examines sites performance on different time basis in terms of: - Hardware parameters: power and temperature. - Radial parameters, among others: Signal-to-Noise Ratio (SNR), number of radial vectors provided by time step, maximum radial range and bearing. - Total uncertainty metrics provided by CODAR: zonal and meridional standard deviations and covariance between both components. - Additionally, a widget embedded in the web interface executes queries against PdE database, providing the chance to compare current time series observed by Tarragona buoy (located within Ebro HF radar spatial domain) and those measured by the closest radar grid point. A thorough analysis of the temporal evolution of the aforementioned parameters allows to define the standard thresholds for each site within which they are considered to be running optimally. In contrast, a site performance could be categorized as sub-optimal if an erratic and/or anomalous behavior is persistently detected in radial parameters values, related to a significant discrepancy from the mean and clearly outside the limits defined by the associated standard deviations. Consequently, a three colored-based alert system is activated according to each site's current status: green (OK), yellow (acceptable, but issue detected) and red (KO). Since this approach is constrained by the fact that it can not state the intrinsic quality of surface current data, a complementary validation analysis is required: HF radar-derived radial and total vectors are compared with observations from a current meter installed in Tarragona buoy. This validation, conducted for the entire 2014, aims to complete the proposed methodology through the exploration of the existence of bearing errors and the evaluation of intrinsic uncertainties related to HF radar technology by means of objective quality indicators.
Railway level crossing obstruction detection using MIMO radar
Arvind Hari Narayanan; Paul Brennan; Ralph Benjamin; Nadia Mazzino; Giovanni Bochetti; Antonio Lancia
Level crossing obstruction detection is an important safety feature that is prominent in rail operations, with detection systems currently deployed use various radio and optical imaging technologies. This paper proposes a prototype radar system for level crossing obstruction detection which utilises the Multiple In - Multiple Out principle. The radar system to be used is an FMCW radar which operates
Design of intelligent testing device for airplane navigation radar
ZENG Xianlin; LI Lizhen
Modern airborne radar systems are very complex electronic equipment systems, high reliability is demanded, and fine functions of automatic detect is needed for guarantee. In this dissertation, we have studied the detect method of a new kind of airborne radar systems. With Embed machinery control as its core, adoption unit wooden blocks type construction, examining the faults of radar one
Radar interferometer calibration of the EISCAT Svalbard Radar and a additional receiver station
NASA Astrophysics Data System (ADS)
Schlatter, N. M.; Grydeland, T.; Ivchenko, N.; Belyey, V.; Sullivan, J.; La Hoz, C.; Blixt, M.
The EISCAT Svalbard Radar has two parabolic dishes. In order to attempt to implement radar aperture synthesis imaging methods three smaller, passive receive array antennas were built. Several science goals for this new receiver system exist, the primary of which is to study so called naturally enhanced ion acoustic lines. In order to compare radar aperture synthesis imaging results with measurements from optical imagers, calibration of the radar interferometer system is necessary. In this work we present the phase calibration of the EISCAT Svalbard interferometer including one array antenna. The calibration was done using the coherent scatter from satellites passing through the radar beam. Optical signatures of the satellite transits provide accurate position for the satellites. Using transits of a number of satellites sufficient for mapping the radar beam, the interferometric cross-phase was fitted within the radar beam. The calibration technique presented in this work will be applied to all antenna pairs of the antenna configuration for future interferometry studies.
NASA Astrophysics Data System (ADS)
Maggs, William Ward
What would you call the next generation of radar for severe weather prediction? NEXRAD, of course. A prototype for the new system was recently completed in Norman, Okla., and by the early 1990s up to 195 stations around the United States will be tracking dangerous weather and sending faster, more accurate, and more detailed warnings to the public.NEXRAD is being built for the Departments of Commerce, Transportation, and Defense by the Unisys Corporation under a $450 million contract signed in December 1987. Th e system will be used by the National Weather Service, the Federal Aviation Administration (FAA), and the U.S. Air Force and Navy. The NEXRAD radar tower in Norman is expected to be operational in October.
Radar: The Cassini Titan Radar Mapper
C. Elachi; M. D. Allison; L. Borgarelli; P. Encrenaz; E. Im; M. A. Janssen; W. T. K. Johnson; R. L. Kirk; R. D. Lorenz; J. I. Lunine; D. O. Muhleman; S. J. Ostro; G. Picardi; F. Posa; C. G. Rapley; L. E. Roth; R. Seu; L. A. Soderblom; S. Vetrella; S. D. Wall; C. A. Wood; H. A. Zebker
The Cassini RADAR instrument is a multimode 13.8 GHz multiple-beam sensor that can operate as a synthetic-aperture radar (SAR) imager, altimeter, scatterometer, and radiometer. The principal objective of the RADAR is to map the surface of Titan. This will be done in the imaging, scatterometer, and radiometer modes. The RADAR altimeter data will provide information on relative elevations in selected
TerraSAR-X high-resolution radar remote sensing: an operational warning system for Rift Valley fever risk.
Vignolles, C�cile; Tourre, Yves M; Mora, Oscar; Imanache, Laurent; Lafaye, Murielle
In the vicinity of the Barkedji village (in the Ferlo region of Senegal), the abundance and aggressiveness of the vector mosquitoes for Rift Valley fever (RVF) are strongly linked to rainfall events and associated ponds dynamics. Initially, these results were obtained from spectral analysis of high-resolution (~10 m) Spot-5 images, but, as a part of the French AdaptFVR project, identification of the free water dynamics within ponds was made with the new high-resolution (down to 3-meter pixels), Synthetic Aperture Radar satellite (TerraSAR-X) produced by Infoterra GmbH, Friedrichshafen/Potsdam, Germany. During summer 2008, within a 30 x 50 km radar image, it was found that identified free water fell well within the footprints of ponds localized by optical data (i.e. Spot-5 images), which increased the confidence in this new and complementary remote sensing technique. Moreover, by using near real-time rainfall data from the Tropical Rainfall Measuring Mission (TRMM), NASA/JAXA joint mission, the filling-up and flushing-out rates of the ponds can be accurately determined. The latter allows for a precise, spatio-temporal mapping of the zones potentially occupied by mosquitoes capable of revealing the variability of pond surfaces. The risk for RVF infection of gathered bovines and small ruminants (~1 park/km(2)) can thus be assessed. This new operational approach (which is independent of weather conditions) is an important development in the mapping of risk components (i.e. hazards plus vulnerability) related to RVF transmission during the summer monsoon, thus contributing to a RVF early warning system. PMID:21080318
Solid state transmitters for modern radar applications
Donald J. Hoft; Fuat Agi
To exemplify the advancing state-of-the-art in radar SS transmitters, this paper describes in some detail three major systems covering a broad range of frequencies: HF, UHF and L-band, which utilize SS transmitters. At HF a 200 kW CW transmitter is described which is applicable in an over-the-horizon radar application; at UHF the Pave Paws (AN\\/FPS-115) long-range phased array radar transmitter
Radar and the DSN. [Deep Space Network
NASA Technical Reports Server (NTRS)
Reid, M. S.
This paper describes how a station, designed, built, and operated for spacecraft communications has been used for scientific planetary radar studies. The thrust of the paper is the mutual advantage that the NASA/JPL Deep Space Network (DSN) and the Goldstone Solar System Radar have derived from sharing some equipment. It is concluded that, by allocating a small fraction of a DSN station's tracking time to planetary radar studies, a superb scientific instrument has been developed.
SBS-based radar true time delay
NASA Astrophysics Data System (ADS)
Bashkansky, Mark; Walker, David; Gulian, Armen; Steiner, Michael
Stimulated Brillouin scattering (SBS) based slow light is considered for application to squint-free (true time delay) steering of phased array radar antennae. Results are presented on true time delay radar requirements, including delay precision and bandwidth. We experimentally investigated the level of delay precision that exists in actual slow-light systems (based on Brillouin scattering). The practical use of SBS to meet the necessary requirements for radar use is discussed.
On Probing Signal Design For MIMO Radar
Petre Stoica; Jian Li; Yao Xie
A multiple-input multiple-output (MIMO) radar system, unlike a standard phased-array radar, can choose freely the probing signals transmitted via its antennas to maximize the power around the locations of the targets of interest, or more generally to approximate a given transmit beampattern, and also to minimize the cross-correlation of the signals reflected back to the radar by the targets of
On Probing Signal Design for MIMO Radar
Jian Li; Petre Stoica; Yao Xie
A MIMO (multi-input multi-output) radar system, unlike a standard phased-array radar, can choose freely the probing signals transmitted via its antennas to maximize the power around the locations of the targets of interest, or more generally to approximate a given transmit beampattern, and also to minimize the cross-correlation of the signals reflected back to the radar by the targets of
Range ambiguity suppression for multiple-input, multiple-output synthetic aperture radar system using azimuth phase coding technique
NASA Astrophysics Data System (ADS)
Guo, Lei; Wang, Robert; Deng, Yunkai; Wang, Wei; Luo, Xiulian
For synthetic aperture radar (SAR), range ambiguity causes a great deterioration in imaging performance. To suppress range ambiguity, the azimuth phase coding (APC) technique stands out for its effectiveness with a low implementation complexity among the available approaches. With proper phase modulation and demodulation, the position of an ambiguous signal is shifted in Doppler spectrum and then part of the ambiguity can be filtered out by an azimuth filter. However, since the suppression performance heavily depends on the system oversampling rate, the APC technique cannot achieve the same suppression performance for a multichannel SAR system compared with a single-channel SAR system. A method to suppress the range ambiguity for multiple-input, multiple-output (MIMO) SAR system based on APC technique is presented. By taking advantage of more phase centers of the MIMO SAR, a proper azimuth beamformer weight vector can be computed to null out the ambiguity position in the azimuth frequency domain and reconstruct the useful signal; thus most of the ambiguity components can be significantly suppressed. Finally, the simulation results validate the effectiveness of the proposed method.
Space Shuttle radar performance predictions and verification
Chau Pham; P. L. Harton; S. K. Simhal
The Space Shuttle Ku-band integrated radar and communication system is operated in a communications mode for transmissions between astronauts in the orbiting Shuttle and mission controllers at the Lyndon B. Johnson Space Center (JSC). In the radar mode the Ku-band system provides a relative position vector, range rate, and angle rates for flight control purposes during operations with other spacecraft.
Ku band integrated radar and communication equipment
L. C. Parode
The Ku Band Subsystem for the NASA Space Shuttle Orbiter operates as a radar during rendezvous with other space vehicles and provides two way communications with the ground through the Tracking and Data Relay Satellite System (TDRSS). As a radar system it searches for, acquires, tracks, and provides the spatial data needed to make a quick and efficient rendezvous. As
Waveform Diversity for Different Multistatic Radar Configurations
I. Bradaric; G. T. Capraro; M. C. Wicks
The multistatic ambiguity function has recently been proposed as a tool for analyzing and designing multistatic radar systems. It was demonstrated through examples that multistatic radar system performances can be improved by shaping the multistatic ambiguity function through waveform selection and adequate weighting of different receivers during pre-detection fusion. In this work we study sensor repositioning as a third way
Passive radar in the high frequency band
Giuseppe Fabrizio; Fabiola Colone; Pierfrancesco Lombardo; Alfonso Farina
Passive radar systems using emitters of opportunity for target detection and tracking have received significant interest recently, especially those which exploit frequency modulated (FM) radio stations and TV transmitters as signal sources. This paper is concerned with passive radar systems that utilize signal sources in the high frequency (HF) band (3-30 MHz), where due to long-distance ionospheric propagation, the transmitter
MESAR, Sampson & Radar Technology for BMD
W. K. Stafford
Over more than 20 years BAE Systems Integrated System Technologies Ltd. (Insyte) in the UK have been participating in the innovative Multi-function Electronically Scanned Adaptive Radar (MESAR) Programme. This has led to the Engineering Development and first of class production contract for the Sampson radar which is to be fitted for the UK T45 Destroyer as part of the PAAMS
Advanced Borehole Radar for Hydrogeology
NASA Astrophysics Data System (ADS)
Sato, M.
Ground Penetrating Radar is a useful tool for monitoring the hydrogeological environment. We have developed GPR systems which can be applied to these purposes, and we will demonstrate examples borehole radar measurements. In order to have longer radar detection range, frequency lower than100MHz has been normally adopted in borehole radar. Typical subsurface fractures of our interests have a few mm aperture and radar resolution is much poorer than a few cm in this frequency range. We are proposing and demonstrating to use radar polarimetry to solve this problem. We have demonstrated that a full-polarimetry borehole radar can be used for characterization of subsurface fractures. Together with signal processing for antenna characteristic compensation to equalize the signal by a dipole antenna and slot antennas, we could demonstrate that polarimetric borehole radar can estimate the surface roughness of subsurface fractures, We believe the surface roughness is closely related to water permeability through the fractures. We then developed a directional borehole radar, which uses optical field sensor. A dipole antenna in a borehole has omni-directional radiation pattern, and we cannot get azimuthal information about the scatterers. We use multiple dipole antennas set around the borehole axis, and from the phase differences, we can estimate the 3-diemnational orientation of subsurface structures. We are using optical electric field sensor for receiver of borehole radar. This is a passive sensor and connected only with optical fibers and does not require any electric power supply to operate the receiver. It has two major advantages; the first one is that the receiver can be electrically isolated from other parts, and wave coupling to a logging cable is avoided. Then, secondary, it can operate for a long time, because it does not require battery installed inside the system. It makes it possible to set sensors in fixed positions to monitor the change of environmental conditions for a long period. We demonstrated this idea using cross- hole borehole radar measurement. We think this method is useful for detecting any changes in hydrogeological situations, which will be useful for subsurface storage such as LNG and nuclear waste.
Structural aspects of meteoroid streams observed by a forward scatter radar system
NASA Astrophysics Data System (ADS)
Cevolani, G.; Gabucci, M. F.; Grassi, G.; Trivellone, G.
Forward scatter (FS) continuous wave (CW) meteor radar observations carried out during 1992-96 over the long baseline Bologna-Lecce in Italy, enable us to investigate the structure of the main meteoroid streams and of the sporadic background by the cumulative distributions vs durations of the recorded echoes. The trends of the mass-distribution of particles belonging to the quoted meteor complexes are discussed in terms of variations of the mass index s against echo durations and in terms of steady-state conditions for each meteor population. The mass index values of the sporadic background are generally higher than for meteor showers in the duration range of 0.1? T?10 s. Observational evidence indicates that the combined cumulative distributions of meteor trails vs peak signal amplitudes and vs durations represent a more sensitive indicator of the meteoroid stream activity, and consequently, of the mass-index variation. The unexpected high proportion of short-lived echoes which produce very faint meteors is interpreted in terms of fragmenting particles which form filaments younger than those present in other parts of the stream. The effects of non-gravitational forces as the solar radiation pressure, the Poynting-Robertson (P-R) effect, mutual collisions, etc., are taken into account to justify the observed widespread radiants and unstable populations of particles.
Classification of radar clutter in an air traffic control environment
The results of an experimental study aimed at the classification of radar clutter encountered on ground-based coherent scanning radar systems used for air traffic control are presented. The clutter signals of interest are primarily those due to birds and to clouds and weather systems. A historical perspective on the radar clutter classification problem is given, and related issues are discussed.
Target Tracking for Multistatic Radar with Transmitter Uncertainty
Zhou, Shengli
Target Tracking for Multistatic Radar with Transmitter Uncertainty Sora Choi, Christian R. Berger CT 06269 ABSTRACT We present a target tracking system for a specific sort of passive radar the numerical load. 1. INTRODUCTION Passive radar is a bi-static system [5] that uses illuminators
NASA Technical Reports Server (NTRS)
Britt, Charles L.
Viewgraphs used in a presentation on wind shear radar simulation are given. Information on a microburst model of radar reflectivity and wind velocity, radar pulse output, the calculation of radar return, microburst power spectrum, and simulation plans are given. A question and answer session is transcribed.
Structure of precipitating systems over Taiwan�s complex terrain during Typhoon Morakot (2009) as revealed by weather radar and rain gauge observations
NASA Astrophysics Data System (ADS)
Liou, Yu-Chieng; Wang, Tai-Chi Chen; Tsai, Yi-Chun; Tang, Yu-Shuang; Lin, Pay-Liam; Lee, Yung-An
This study documents from an observational perspective the structure of precipitation systems over the complex topography of Taiwan as Typhoon Morakot (2009) impinged on the island on 8 August 2009. An advanced multiple-Doppler radar synthesis technique particularly designed for dealing with non-flat surfaces is applied to analyze the three-dimensional wind fields over the ocean and terrain. In the northern and southern portion of the analysis domain where the mountain slope is relatively gentle and steep, respectively, the radar reflectivity measurements indicate that the precipitation systems exhibit very distinct features, namely, horizontal translation in the north and abrupt intensification in the south. While still far from the southern mountainous region, a north-south oscillation of an east-west-oriented band of strong radar reflectivity (>40 dBZ) with a horizontal span of 20 km is observed. Along the mountain slopes, the band of strong radar reflectivity has a much wider north-south extent. Both the radar and rain gauge observations show that the major precipitation is primarily confined to the windward side of the mountains. An analysis of the saturated Brunt-V�is�l� frequency reveals that the upstream atmosphere is statically unstable, which implies that the lifting of the incoming convective cells by the topography will easily trigger precipitation. Thus, most of the moisture will be consumed before the air reaches the leeward side of the mountains. The long duration and the wide range of heavy precipitation in the mountainous regions resulted in a record-breaking average (over the gauges) rainfall amount of 2000 mm over 4 days. The prevailing winds approaching the mountains are from the west. The cross-barrier wind speed has a maximum (?40 m s-1) above the mountain crest that can be reasonably explained by a simplified shallow water model. The capability of applying the weather radar to provide a reliable quantitative estimate of the rainfall over a large area with high temporal and spatial resolution is demonstrated using dual-polarimetric radar data. The potential applications of the knowledge of the wind and precipitation characteristics in hydrology and other fields are addressed in this manuscript.
NASA Technical Reports Server (NTRS)
Muhleman, Duane O.; Butler, Bryan J.; Grossman, Arie W.; Slade, Martin A.
VLA radar-reflected flux-density mappings have yielded full disk images of Mars which reveal near-surface features, including a region in the Tharsis volcano area that displayed no echo to the very low level of the radar-system noise. This feature is interpreted as a deposit of dust or ash whose density is less than about 0.5 g/cu cm; it must be several meters thick, and may be much deeper. The most strongly reflecting geological feature was the south polar ice cap, which is interpretable as arising from nearly-pure CO2 or H2O ice, with less than 2 vol pct Martian dust. Only one anomalous reflecting feature was identified outside the Tharsis region.
Surveillance radars - State of the art, research and perspectives
NASA Astrophysics Data System (ADS)
Farina, A.; Galati, G.
An assessment is made of the signal processing techniques currently employed by ground-based surveillance radars, and a projection is made of those techniques that are likely to be applied to such radars in the future. Further applications of such techniques in such diverse fields as multistatic and dispersed radars, AEW, and space-based radars are also considered. Attention is given to prospective technological advancements that will facilitate radar systems' future dealings with antiradiation missiles and stealth aircraft, which may include digital beam forming, adaptivity, and high resolution multidimensional processing and target classification. The advantages of multistatic radar are examined in detail.
UWB Array-Based Radar for Landmine Detection
Alexander Yarovoy; Pascal Aubry; Pidio Lys; Leo Ligthart
In this paper, the development of an UWB array-based time-domain radar sensor is described. The radar sensor is designed to be used within a vehicle-mounted multi-sensor system for humanitarian demining. The main novelty of the radar lies in the modular approach, design of the antenna system and waveform of the transmit antenna feeding pulse. The radar has focusing capability via
Distributed Coherent Aperture Measurements for Next Generation BMD Radar
S. Coutts; K. Cuomo; J. McHarg; F. Robey; D. Weikle
This paper describes the distributed coherent aperture work being carried out at MIT Lincoln Laboratory in support of the next generation radar (NGR) program under the direction of the Radar Systems Technology (RST) group within the Missile Defense Agency\\/Advanced Systems (MDA\\/AS) Directorate. The NGR concept achieves transportability and high-radar sensitivity by coherently combining multiple distributed radar apertures in a building
NASA Technical Reports Server (NTRS)
Quirk, Kevin J.; Srinivasan, Meera
The minimum-shift-keying (MSK) radar waveform is formed by periodically extending a waveform that separately modulates the in-phase and quadrature- phase components of the carrier with offset pulse-shaped pseudo noise (PN) sequences. To generate this waveform, a pair of periodic PN sequences is each passed through a pulse-shaping filter with a half sinusoid impulse response. These shaped PN waveforms are then offset by half a chip time and are separately modulated on the in-phase and quadrature phase components of an RF carrier. This new radar waveform allows an increase in radar resolution without the need for additional spectrum. In addition, it provides self-interference suppression and configurable peak sidelobes. Compared strictly on the basis of the expressions for delay resolution, main-lobe bandwidth, effective Doppler bandwidth, and peak ambiguity sidelobe, it appears that bi-phase coded (BPC) outperforms the new MSK waveform. However, a radar waveform must meet certain constraints imposed by the transmission and reception of the modulation, as well as criteria dictated by the observation. In particular, the phase discontinuity of the BPC waveform presents a significant impediment to the achievement of finer resolutions in radar measurements a limitation that is overcome by using the continuous phase MSK waveform. The phase continuity, and the lower fractional out-of-band power of MSK, increases the allowable bandwidth compared with BPC, resulting in a factor of two increase in the range resolution of the radar. The MSK waveform also has been demonstrated to have an ambiguity sidelobe structure very similar to BPC, where the sidelobe levels can be decreased by increasing the length of the m-sequence used in its generation. This ability to set the peak sidelobe level is advantageous as it allows the system to be configured to a variety of targets, including those with a larger dynamic range. Other conventionally used waveforms that possess an even greater spectral efficiency than the MSK waveform, such as linear frequency modulation (LFM) and Costas frequency hopping, have a fixed peak sidelobe level that is therefore not configurable, and can be exceeded by high contrast targets. Furthermore, in the case of a multistatic experiment observing a target in motion, self-interference from the transmitter to the receiver is mitigated by the MSK waveform. Waveforms that have delay Doppler coupling, such as LFM, provide no such protection.
Radar observations in low earth orbit
NASA Astrophysics Data System (ADS)
Mehrholz, Dieter
This paper presents an overview on radar techniques for the observation of space debris in low Earth orbits which were developed at FGAN in the frame of DARA and ESA/ESOC study contracts for the employment of the Tracking and Imaging Radar (TIRA) system in the past five years. For space debris observations TIRA is mainly operated in two different modes: In a tracking mode and in a beam-park mode of operation. Methods and algorithms were developed to analyse raw radar data, to compute radar images, and to estimate physical characteristics of space objects like size, shape, attitude, orbit, orbital lifetime, ballistic coefficient, mass, and material composition.
A satellite-based radar wind sensor
NASA Technical Reports Server (NTRS)
Xin, Weizhuang
The objective is to investigate the application of Doppler radar systems for global wind measurement. A model of the satellite-based radar wind sounder (RAWS) is discussed, and many critical problems in the designing process, such as the antenna scan pattern, tracking the Doppler shift caused by satellite motion, and backscattering of radar signals from different types of clouds, are discussed along with their computer simulations. In addition, algorithms for measuring mean frequency of radar echoes, such as the Fast Fourier Transform (FFT) estimator, the covariance estimator, and the estimators based on autoregressive models, are discussed. Monte Carlo computer simulations were used to compare the performance of these algorithms. Anti-alias methods are discussed for the FFT and the autoregressive methods. Several algorithms for reducing radar ambiguity were studied, such as random phase coding methods and staggered pulse repitition frequncy (PRF) methods. Computer simulations showed that these methods are not applicable to the RAWS because of the broad spectral widths of the radar echoes from clouds. A waveform modulation method using the concept of spread spectrum and correlation detection was developed to solve the radar ambiguity. Radar ambiguity functions were used to analyze the effective signal-to-noise ratios for the waveform modulation method. The results showed that, with suitable bandwidth product and modulation of the waveform, this method can achieve the desired maximum range and maximum frequency of the radar system.
Optimization and performance assessment of a self-aligned heterodyne laser radar system for surface displacement monitoring
NASA Astrophysics Data System (ADS)
Rodr�guez, Alejandro; Garcia, David; Comeron, Adolfo; Dios, Federico
The optimization and performance assessment of a reference-beam, continuous-wave, heterodyne low-power laser radar prototype is presented, based on previous homodyne prototypes. It measures both magnitude and sign of the radial component of the displacement velocity. The basic set-up includes a low power (~3 mW) commercial HeNe laser, a beam-splitter, an acousto-optic modulator, and a two-lens system that both focuses the transmitted beam on the target surface and collects the scattered light. Both the reference beam and the radiation collected are focussed onto a Si avalanche photo-detector. The self-aligned configuration of the receiver makes possible, theoretically, to perform optimal mixing between the received scattered radiation and the reference beam. The resulting electrical signal is fed to a transimpedance amplifier and displayed on a spectrum analyser. Laboratory experiments employing as a target the rim of a 50 cm-diameter rotating wheel placed at several distances have been performed. Results concerning detected signal-to-noise ratio, detected-signal spectral width, accuracy of the radial component of the velocity under measurement and system working range will be presented and discussed.
Spaceborne Imaging Radar Project
NASA Technical Reports Server (NTRS)
Herman, Neil
In June of 1985 the Project Initiation Agreement was signed by the Jet Propulsion Laboratory and the NASA Office of Space Science and Applications for the Spaceborne Imaging Radar Project (SIR). The thrust of the Spaceborne Imaging Radar Project is to continue the evolution of synthetic aperture radar (SAR) science and technology developed during SEASAT, SIR-A and SIR-B missions to meet the needs of the Earth Observing System (EOS) in the mid 1990's. As originally formulated, the Project plans were for a reflight of the SIR-B in 1987, the development of a new SAR, SIR-C, for missions in mid 1989 and early 1990, and the upgrade of SIR-C to EOS configuration with a qualification flight aboard the shuttle in the 1993 time frame (SIR-D). However, the loss of the shuttle Challenger has delayed the first manifest for SIR to early 1990. This delay prompted the decision to drop SIR-B reflight plans and move ahead with SIR-C to more effectively utilize this first mission opportunity. The planning for this project is discussed.
An analysis of the data collection modes of a digital weather radar system with respect to significant severe weather features�
Neyland, Michael Arthur
LIST OF ACROBYMS EWER CAPPI CAZM DVIP PPI bounded weak echo region constant altitude plan position indi. cator constant altitude reflectivity map digital video integrator and processor plan position indicator. minimum detectable signal PRF... of radar, it was recognized that the device could locate and tracR areas of severe weather and precipitation. Since that time, radar has come to be considered one of the most important tools available to the meteoro- logist for the detection of severe...
Stereo radar for mapping and interpretation
NASA Technical Reports Server (NTRS)
Graham, L.
The use of terrain imaging radar to extract elevation information by stereo viewing and measurement is discussed. Either a three dimensional visual model or elevation measurements may be obtained by simultaneous viewing or differential measurement of images obtained by a side-looking radar from two different flightpaths. Expressions describing radar image geometry, model vertical exaggeration, and stereo measurement accuracy are derived. The dependence of the exaggeration and accuracy on system parameters and key system errors is derived, discussed, and illustrated by application to several airborne and spaceborne systems and system concepts, and the results of some preliminary measurements of imagery from two airborne and one spaceborne system are given.
Analysis of thin-wire ground penetrating radar systems for buried target detection, using a hybrid MoM-FDTD technique
N. Farnoosh; A. Shoory; R. Moini; S. H. H. Sadeghi
A hybrid method combining the finite difference time domain (FDTD) method and the method of moments (MoM) in the frequency domain is proposed to model the electromagnetic behavior of a realistic ground penetrating radar (GPR) system. The GPR is a non-destructive testing (NDT) technique. It consists of a broadband thin-wire vee-dipole antenna located in the vicinity of a lossy ground
Use of Sandia's Central Receiver Test Facility as a high-intensity heat source for testing missile nose-cone (Radome) radar systems
Porter, D.R.
A series of tests at Sandia's Central Receiver Test Facility in support of the US Navy's SM-2 Blk 2 Radome Improvement Program is described. The CRTF was the source of high-intensity solar radiation for testing onboard radar-tracking systems under heating conditions intended to simulate those that occur in supersonic flight. Also discussed are the hardware used and the software developed at the CRTF.
Fully Integrated SiGe-BiCMOS Receiver(RX) and Transmitter(TX) Chips for 76.5 GHz FMCW Automotive Radar Systems Including Demonstrator Board Design
R. Reuter; H. Li; I. To; Y. Yin; A. Ghazinour; D. Jahn; D. Morgan; J. Feige; P. Welch; S. Braithwaite; B. Knappenberger; D. Scheitlin; J. John; M. Huang; P. Wennekers; M. Tutt; C. Trigas; J. Kirchgessner
Advancements in SiGe device development enable the realization of 76.5 GHz FMCW automotive long range radar systems using relatively low-cost silicon technology. This paper presents fully integrated receiver (RX) and transmitter (TX) circuits for wide temperature range operations. The TX chips consists of a VCO with two stage power amplifier, frequency divider chain, power detector circuit and operational amplifier to
STAP with medium PRF mode for non-side-looking airborne radar
Yong-Liang Wang; Zheng Bao; Ying-Ning Peng
Space-time adaptive processing (STAP) has been widely discussed for airborne radar systems to improve the system performance of detecting targets. This is especially true for airborne early warning (AEW) radar, which should find long-range and small radar cross section (RCS) targets such as the stealth aircraft and missiles. However, in existing airborne radar literature, STAP is mainly considered for clutter
MIMO Radar with Frequency Diversity Jun Jason Zhang and Antonia Papandreou-Suppappola
Nehorai, Arye
MIMO Radar with Frequency Diversity Jun Jason Zhang and Antonia Papandreou-Suppappola email@example.com Abstract-- We propose a new multiple-input, multiple-output (MIMO) radar system with colocated antennas. The proposed MIMO radar system results in a radar array with frequency-division multiplexing that can also
Understanding the relationships between radar response patterns and the bio- and geophysical parameters of urban areas
Zong-Guo Xia; Floyd M. Henderson
This paper reviews the current understanding of the relationships between radar response patterns and the bio- and geophysical parameters of urban areas. Specifically, it examines the effects of radar system, ground target, and environmental factors on the intensity and pattern of radar returns from urban features. System parameters considered include radar signal wavelength, polarization, incident angle, and look direction. Ground
UAV based collision avoidance radar sensor
Young K. Kwag; C. H. Chung
In this paper, the critical requirement for obstacle awareness and avoidance is assessed with the compliance of the equivalent level of safety regulation, and then the collision avoidance radar sensor system is presented with the key design parameters for the requirement of the smart unmanned aerial vehicle in low-altitude flight. Based on the assessment of various sensors, small-sized radar sensor
Meteor radiant mapping with MU radar
NASA Technical Reports Server (NTRS)
Watanabe, Jun-Ichi; Nakamura, Tsuko; Tsuda, T.; Tsutsumi, M.; Miyashita, A.; Yoshikawa, M.
The radiant point mapping of meteor showers with the MU radar by using a modified mapping method originally proposed by Morton and Jones (1982) was carried out. The modification is that each meteor echo was weighted by using the beam pattern of the radar system. A preliminary result of the radiant point mapping of the Geminids meteor shower in 1989 is presented.
Analysis of UWB Radar Sensor Networks
Stefania Bartoletti; Andrea Conti; Andrea Giorgetti
Radar sensor networks (RSNs) are gaining importance in the context of passive localization and tracking. The performance of RSNs is affected by disturbances, system's parameters, network topology, and the number of radar elements. In this paper, we derive a unified analytical framework that takes all this aspects into account and allows the derivation of probability of detection and localization uncertainty.
GSFC short pulse radar, JONSWAP-75
NASA Technical Reports Server (NTRS)
Levine, D. M.; Walton, W. T.; Eckerman, J.; Kutz, R. L.; Dombrowski, M.; Kalshoven, J. E., Jr.
In September 1975, the Goddard Space Flight Center operated a short pulse radar during ocean wave measuring experiments off the coast of West Germany in the North Sea. The experiment was part of JONSWAP-75. The radar system and operations during the experiment are described along with examples of data.
European near-Earth object radar
NASA Astrophysics Data System (ADS)
Zaitsev, Alexander L.
Radar astronomy paradox (RAP): practically everybody agree with essential contributions of active radar observations to Solar System and especially to near-Earth object (NEO) explorations, but despite everything prefer to develop new and new passive telescopes and disposable space missions, only, and nobody want to build at least one dedicated multipurpose radar telescope (neither Arecibo nor Goldstone and Evpatoria radars were created as dedicated radar astronomy instruments). Also, as of June 2002, among of 188 radar detected asteroids and comets there are only 3 NEOs, which were investigated in Europe, with single European radar facility, sited in Evpatoria. The main reason of such deep gap is a low sensitivity of Evpatoria radar, which is in 10 and 300 times less powerful than Goldstone and Arecibo. Therefore, I guess the first dedicated European NEO Radar (ENEOR) is earnestly needful now. From time to time we discuss this problem, but it is not solve for the present moment, perhaps because of above formulated RAP. Origin and concept of the ENEOR, as well as the ENEOR project, based on the being under construction 64-m Sardinia Radio Telescope, will be presented below.
Robust Sparse Sensing Using Weather Radar
NASA Astrophysics Data System (ADS)
Mishra, K. V.; Kruger, A.; Krajewski, W. F.; Xu, W.
The ability of a weather radar to detect weak echoes is limited by the presence of noise or unwanted echoes. Some of these unwanted signals originate externally to the radar system, such as cosmic noise, radome reflections, interference from co-located radars, and power transmission lines. The internal source of noise in microwave radar receiver is mainly thermal. The thermal noise from various microwave devices in the radar receiver tends to lower the signal-to-noise ratio, thereby masking the weaker signals. Recently, the compressed sensing (CS) technique has emerged as a novel signal sampling paradigm that allows perfect reconstruction of signals sampled at frequencies lower than the Nyquist rate. Many radar and remote sensing applications require efficient and rapid data acquisition. The application of CS to weather radars may allow for faster target update rates without compromising the accuracy of target information. In our previous work, we demonstrated recovery of an entire precipitation scene from its compressed-sensed version by using the matrix completion approach. In this study, we characterize the performance of such a CS-based weather radar in the presence of additive noise. We use a signal model where the precipitation signals form a low-rank matrix that is corrupted with (bounded) noise. Using recent advances in algorithms for matrix completion from few noisy observations, we reconstruct the precipitation scene with reasonable accuracy. We test and demonstrate our approach using the data collected by Iowa X-band Polarimetric (XPOL) weather radars.
MIMO Radar Moving Target Detection in Homogeneous Clutter
Haimovich, Alexander
1 MIMO Radar Moving Target Detection in Homogeneous Clutter Qian He, Nikolaus H. Lehmann, Rick S-output (MIMO) radar approach employing widely-dispersed transmit and receive an- tennas is studied the overall system to "view" the target simultaneously from several different directions. The MIMO radar
Code of Federal Regulations, 2010 CFR
...2010-10-01 2010-10-01 false Radar-T/OC. 32.15-30 Section 32...Navigation Equipment � 32.15-30 Radar�T/OC. All tankships of 1,600...coastwise service must be fitted with a marine radar system for surface navigation....
46 CFR 28.400 - Radar and depth sounding devices.
Code of Federal Regulations, 2010 CFR
...2010-10-01 2010-10-01 false Radar and depth sounding devices. 28.400...16 Individuals on Board � 28.400 Radar and depth sounding devices. (a) Each vessel must be fitted with a general marine radar system for surface navigation with a...
Code of Federal Regulations, 2011 CFR
...2011-10-01 2011-10-01 false Radar-T/OC. 32.15-30 Section 32...Navigation Equipment � 32.15-30 Radar�T/OC. All tankships of 1,600...coastwise service must be fitted with a marine radar system for surface navigation....
46 CFR 28.400 - Radar and depth sounding devices.
Code of Federal Regulations, 2011 CFR
...2011-10-01 2011-10-01 false Radar and depth sounding devices. 28.400...16 Individuals on Board � 28.400 Radar and depth sounding devices. (a) Each vessel must be fitted with a general marine radar system for surface navigation with a...
Spectrum Sharing with Rotating Radar: Implications for Cognitive Radio Rendezvous
Buehrer, R. Michael
Spectrum Sharing with Rotating Radar: Implications for Cognitive Radio Rendezvous Jeffrey D. Poston in time & frequency. Even prior work specifically on sharing with radar systems typically proposes switching to another frequency upon detection of radar activity. An opportunity exists for a more
A microwave interferometer radar for spacecraft rendezvous missions
Werner Koppl; Rusty Smith
A microwave interferometer docking radar is described. This system employs a pulse radar to measure the relative angles between two spacecraft at close ranges. A phase interferometer is implemented to provide accurate measurements of the angular location of the target spacecraft. A preliminary design of an interferometer radar is performed to illustrate the advantages of this approach.
New techniques applied to air-traffic control radars
CHARLES E. MUEHE; LINCOLN CARTLEDGE; WILLIAM H. DRURY; EDWARD M. HOFSTETTER; MELVIN LABITT; PETER B. McCORISON; VINCENT J. SFERRINO
During the past two years a program has been carried out to show how new techniques can greatly improve the performance of radars used for air-traffic control. A survey of problems associated with presently used radars was undertaken. This survey indicates that primary radar in an automated air-traffic control system can be made significantly more effective by the use of
FR/GE/US radar receiver pulse compression ratio
NASA Astrophysics Data System (ADS)
This ITOP describes procedures for measuring radar receiver pulse compression ratio. Procedures described are limited to measuring the performance of the radar receiver under test as a major component. Receiver pulse compression ratio must be measured with the total radar system.
Ultrawideband radar clutter measurements of forested terrain, 1991--1992
D. M. Sheen; R. H. Severtsen; J. M. Prince; K. C. Davis; H. D. Collins
The ultrawideband (UWB) radar clutter measurements project was conducted to provide radar clutter data for new ultrawideband radar systems which are currently under development. A particular goal of this project is to determine if conventional narrow band clutter data may be extrapolated to the UWB case. This report documents measurements conducted in 1991 and additional measurements conducted in 1992. The
Specific Emitter Identification: Analysis on real radar signal data
S. D'Agostino; G. Foglia; D. Pistoia
This paper focuses on the specific emitter identification (SEI) technique applied to electronic support measure (ESM) systems. The main idea is to analyze the radar pulses and characterize those by extracting features that should be different for each radar. In the paper, feature extraction algorithms are used to characterize the radar pulses: a measurement campaign has been conducted to acquire
Recursive Bayesian electromagnetic refractivity estimation from radar sea clutter
Buckingham, Michael
from radar sea clutter, Radio Sci., 42, RS2014, doi:10.1029/2005RS003423. 1. Introduction [2] The determination of microwave propagation con- ditions in the troposphere is important for assessing the performance of both communications and radar systems. In general, radar coverage over the sea surface
Ultrawideband Random Noise Radar Design for Through-Wall Surveillance
Chieh-Ping Lai; RAM M. NARAYANAN
We have developed an ultrawideband (UWB) random noise radar for through-wall surveillance applications. The operating frequency is in the ultrahigh frequency range, and the entire system is built around the concept of software defined radio. The radar receiver performance is statistically evaluated using both simulation studies and actual measurement results. We also discuss the phenomena of interference level and radar
Profiles of radio refractive index and humidity derived from radar wind profilers and the Global Positioning System
NASA Astrophysics Data System (ADS)
Gossard, Earl E.; Gutman, Seth; Stankov, B. Boba; Wolfe, Daniel E.
It has often been pointed out that the Bragg backscatter of radar waves from elevated turbulent layers is very highly correlated with the height gradient of radio refractive index (RI) through these layers. However, many users need the profiles of RI, or the associated humidity, rather than profiles of their gradients. Simple integration of the gradients is usually not feasible because of ground or sea clutter and because biological scatterers such as insects and birds often severely contaminate the lower range gates. We show that if the total height-integrated RI is independently available (say, from the Global Positioning System (GPS)), and if the surface value of RI is known, the profiles of RI are retrievable with good accuracy. For those profiler systems equipped with a radio acoustic sounding system to measure temperature, the humidity is also retrievable. The method is demonstrated with data collected in southern California, where 7 hours of profiler data were recorded at 449 MHZ along with GPS data. Three radiosonde balloons were launched during the period, and the profiles of RI from the balloon and the profiler are compared. The advantages of the system are its invulnerability to nonprecipitating clouds (at frequencies of 449 MHZ or lower) and that it uses only facilities that will soon be deployed globally. Simulations are used to assess errors from various factors such as loss of sign of the gradient of the potential RI (important especially during some frontal events) and the presence of biological contaminants in some geographical areas (such as coastal zones and some agricultural areas at night).
Study to investigate and evaluate means of optimizing the radar function for the space shuttle. [(pulse radar)
NASA Technical Reports Server (NTRS)
Results are discussed of a study to define a radar and antenna system which best suits the space shuttle rendezvous requirements. Topics considered include antenna characteristics and antenna size tradeoffs, fundamental sources of measurement errors inherent in the target itself, backscattering crosssection models of the target and three basic candidate radar types. Antennas up to 1.5 meters in diameter are within specified installation constraints, however, a 1 meter diameter paraboloid and a folding, four slot backfeed on a two gimbal mount implemented for a spiral acquisition scan is recommended. The candidate radar types discussed are: (1) noncoherent pulse radar (2) coherent pulse radar and (3) pulse Doppler radar with linear FM ranging. The radar type recommended is a pulse Doppler with linear FM ranging. Block diagrams of each radar system are shown.
SIR-C\\/X-SAR: An Advanced Radar
Frederick Stuhr; Rolando Jordan; Marian Werner
The Spaceborne Imaging Radar-C\\/X-band Synthetic Aperture Radar (SIR-C\\/X-SAR) is the most advanced civilian spaceborne radar yet flown. It is the world's first spaceborne multifrequency, multipolarization system and incorporates a number of advanced capabilities and innovative features and modes, including SCANSAR and interferometry. SIR-C\\/X-SAR was successfully flown twice in 1994 aboard the Shuttle Endeavour as part of an international imaging radar
New Electronically Scanned Array Radars for Airborne Applications
Wolfgang Holpp; Christian Worning
High performance fire control radars like CAPTOR for Eurofighter attain the limit of technical performance that can be realised by systems with mechanically scanned antennas. Today active electronically scanned array (AESA) radars are about to revolutionise the capabilities of state-of-the-art fighter aircraft. In the frame of different European activities towards E-Scan Radar the CAESAR (CAPTOR AESA Radar) demonstrator has successfully
Sub-band processing for grating lobe disambiguation in sparse arrays
NASA Astrophysics Data System (ADS)
Hersey, Ryan K.; Culpepper, Edwin
Combined synthetic aperture radar (SAR) and ground moving target indication (GMTI) radar modes simultaneously generate SAR and GMTI products from the same radar data. This hybrid mode provides the benefit of combined imaging and moving target displays as well as improved target recognition. However, the differing system, antenna, and waveform requirements between SAR and GMTI modes make implementing the hybrid mode challenging. The Air Force Research Laboratory (AFRL) Gotcha radar has collected wide-bandwidth, multi-channel data that can be used for both SAR and GMTI applications. The spatial channels on the Gotcha array are sparsely separated, which causes spatial grating lobes during the digital beamforming process. Grating lobes have little impact on SAR, which typically uses a single spatial channel. However, grating lobes have a large impact on GMTI, where spatial channels are used to mitigate clutter and estimate the target angle of arrival (AOA). The AOA ambiguity has a significant impact in the Gotcha data, where detections from the sidelobes and skirts of the mainlobe wrap back into the main scene causing a significant number of false alarms. This paper presents a sub-banding method to disambiguate grating lobes in the GMTI processing. This method divides the wideband SAR data into multiple frequency sub-bands. Since each sub-band has a different center frequency, the grating lobes for each sub-band appear at different angles. The method uses this variation to disambiguate target returns and places them at the correct angle of arrival (AOA). Results are presented using AFRL Gotcha radar data.
Fusion of data received FM-CW radar and AIS � analysis of functionality: Topic 3. Radar application
Stupak Tadeusz; Wawruch Ryszard; P. S?awomir
Development of Frequency Modulated Continuous Wave (FM-CW) radars and universal shipborne Automatic Identification System (AIS) creates new questions in practical application of these technologies for purposes of ships traffic monitoring and control. Accuracy of FM-CW radar distance measurement, not achievable for pulse radars, causes questions of correctness of charted data presented by ECDIS and information about ship's position transmitted by
Spaceborne Synthetic Aperture Radar (SAR) Systems: State of the Art and Future Developments
Alberto Moreira; Gerhard Krieger
This paper first summarizes the state of the art in spaceborne SAR systems and applications. The second part of this paper gives an overview of new concepts, techniques and technologies for future SAR systems, allowing an increase of flexibility in the SAR operation mode as well as a reduction in the overall system costs. Several innovative concepts and technologies as
Electronically scanned millimeter-wave radar for pre-crash safety and adaptive cruise control system
S. Tokoro; K. Kuroda; A. Kawakubo; K. Fujita; H. Fujinami
An objective of developing intelligent transport systems (ITS) is to enhance driving convenience. As an ITS technology that meets this objective, an adaptive cruise control (ACC) system has already been commercialized. Another objective is to enhance the vehicle safety performance. With the aim of attaining this objective, we have developed a Pre-crash Safety system by evolving the ITS technology used
A Parallel, High-Fidelity Radar Model
NASA Astrophysics Data System (ADS)
Horsley, M.; Fasenfest, B.
Accurate modeling of Space Surveillance sensors is necessary for a variety of applications. Accurate models can be used to perform trade studies on sensor designs, locations, and scheduling. In addition, they can be used to predict system-level performance of the Space Surveillance Network to a collision or satellite break-up event. A high fidelity physics-based radar simulator has been developed for Space Surveillance applications. This simulator is designed in a modular fashion, where each module describes a particular physical process or radar function (radio wave propagation & scattering, waveform generation, noise sources, etc.) involved in simulating the radar and its environment. For each of these modules, multiple versions are available in order to meet the end-users needs and requirements. For instance, the radar simulator supports different atmospheric models in order to facilitate different methods of simulating refraction of the radar beam. The radar model also has the capability to use highly accurate radar cross sections generated by the method of moments, accelerated by the fast multipole method. To accelerate this computationally expensive model, it is parallelized using MPI. As a testing framework for the radar model, it is incorporated into the Testbed Environment for Space Situational Awareness (TESSA). TESSA is based on a flexible, scalable architecture, designed to exploit high-performance computing resources and allow physics-based simulation of the SSA enterprise. In addition to the radar models, TESSA includes hydrodynamic models of satellite intercept and debris generation, orbital propagation algorithms, optical brightness calculations, optical system models, object detection algorithms, orbit determination algorithms, simulation analysis and visualization tools. Within this framework, observations and tracks generated by the new radar model are compared to results from a phenomenological radar model. In particular, the new model will be used to simulate an S-band upgrade to the space fence.