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GPS Supplemental Navigation Systems for Use During the Transition to a Sole-Means-GPS
Stanford University
GPS Supplemental Navigation Systems for Use During the Transition to a Sole-Means-GPS National as part of the transition to sole-means-GPS navigation in the United States. GPS based systems are also radio-navigation aids to provide a redundant navigation system alongside GPS/WAAS during the transition
Autonomous Navigation System Based on GPS
Zhaoxiang Liu; Gang Liu
An autonomous navigation system based on GPS was developed. The system was composed of the under-controlling part and the\\u000a decision-making part; the two parts communicated with each other via wireless data transmission modules. The under-controlling\\u000a part included the ARM7 microprocessor, the wireless data transmission module, the GPS receiver and the mobile quadricycle.\\u000a The decision-making part included the laptop and the
Flight test on GPS navigation performance using low cost GPS navigation system
K. Koremura
Summary form only given. The author describes a flight test performed in Japan using a GPS (Global Positioning System) navigation system. A low-cost C\\/A code GPS navigation system (Pioneer AVIC-1) which consists of a three-channel sequential receiver and map display was installed on an experimental aircraft together with VOR\\/DME airborne experiment and a baro-altimeter. The data collected are position, velocity
RFID and GPS integrated navigation system for the visually impaired
Kumar Yelamarthi; Daniel Haas; Daniel Nielsen; Shawn Mothersell
This paper describes an RFID and GPS integrated navigation system, Smart-Robot (SR) for the visually impaired. The SR uses RFID and GPS based localization while operating indoor and outdoor respectively. The portable terminal unit is an embedded system equipped with an RFID reader, GPS, and analog compass as input devices to obtain location and orientation. The SR can guide the
Autonomous navigation system based on GPS and magnetometer data
NASA Technical Reports Server (NTRS)
Julie, Thienel K. (Inventor); Richard, Harman R. (Inventor); Bar-Itzhack, Itzhack Y. (Inventor)
This invention is drawn to an autonomous navigation system using Global Positioning System (GPS) and magnetometers for low Earth orbit satellites. As a magnetometer is reliable and always provides information on spacecraft attitude, rate, and orbit, the magnetometer-GPS configuration solves GPS initialization problem, decreasing the convergence time for navigation estimate and improving the overall accuracy. Eventually the magnetometer-GPS configuration enables the system to avoid costly and inherently less reliable gyro for rate estimation. Being autonomous, this invention would provide for black-box spacecraft navigation, producing attitude, orbit, and rate estimates without any ground input with high accuracy and reliability.
The development of an integrated GPS\\/INS\\/sonar navigation system for autonomous underwater vehicle navigation
M. Bennamoun; B. Boashash; F. Faruqi; M. Dunbar
The need to successfully navigate in an underwater environment is rapidly becoming an important concern in the 1990's. This paper presents the development of an integrated navigation system for autonomous underwater vehicles (AUV) using GPS, INS and sonar. This paper discusses the existing problems with sub-sea navigation, the motivation for an integrated system, the mathematical derivation for an integrated GPS\\/INS\\/sonar
77 FR 13350 - Certain Automotive GPS Navigation Systems, Components Thereof, and Products Containing Same...
Federal Register 2010, 2011, 2012, 2013, 2014
...TRADE COMMISSION [Investigation No. 337-TA-814] Certain Automotive GPS Navigation Systems, Components Thereof, and Products...sale within the United States after importation of certain automotive GPS navigation systems, components thereof, and...
High accuracy autonomous navigation using the global positioning system (GPS)
NASA Technical Reports Server (NTRS)
Truong, Son H.; Hart, Roger C.; Shoan, Wendy C.; Wood, Terri; Long, Anne C.; Oza, Dipak H.; Lee, Taesul
The application of global positioning system (GPS) technology to the improvement of the accuracy and economy of spacecraft navigation, is reported. High-accuracy autonomous navigation algorithms are currently being qualified in conjunction with the GPS attitude determination flyer (GADFLY) experiment for the small satellite technology initiative Lewis spacecraft. Preflight performance assessments indicated that these algorithms are able to provide a real time total position accuracy of better than 10 m and a velocity accuracy of better than 0.01 m/s, with selective availability at typical levels. It is expected that the position accuracy will be increased to 2 m if corrections are provided by the GPS wide area augmentation system.
Evaluation of Mobile Phone Interference With Aircraft GPS Navigation Systems
NASA Technical Reports Server (NTRS)
Pace, Scott; Oria, A. J.; Guckian, Paul; Nguyen, Truong X.
This report compiles and analyzes tests that were conducted to measure cell phone spurious emissions in the Global Positioning System (GPS) radio frequency band that could affect the navigation system of an aircraft. The cell phone in question had, as reported to the FAA (Federal Aviation Administration), caused interference to several GPS receivers on-board a small single engine aircraft despite being compliant with data filed at the time with the FCC by the manufacturer. NASA (National Aeronautics and Space Administration) and industry tests show that while there is an emission in the 1575 MHz GPS band due to a specific combination of amplifier output impedance and load impedance that induces instability in the power amplifier, these spurious emissions (i.e., not the intentional transmit signal) are similar to those measured on non-intentionally transmitting devices such as, for example, laptop computers. Additional testing on a wide sample of different commercial cell phones did not result in any emission in the 1575 MHz GPS Band above the noise floor of the measurement receiver.
Testing and evaluation of an integrated GPS\\/INS system for small AUV navigation
X. Yun; E. R. Bachmann; R. B. McGhee; R. H. Whalen; R. L. Roberts; R. G. Knapp; A. J. Healey; M. J. Zyda
A Small Autonomous Underwater Vehicle Navigation System (SANS) is being developed at the Naval Postgraduate School. The SANS is an integrated Global Positioning System\\/Inertial Navigation System (GPS\\/INS) navigation system composed of low-cost and small-size components. It is designed to demonstrate the feasibility of using a low-cost strap-down inertial measurement unit (IMU) to navigate between intermittent GPS fixes. The present hardware
Autonomous reconfigurable GPS/INS navigation and pointing system for rendezvous and docking
NASA Technical Reports Server (NTRS)
Upadhyay, Triveni N.; Cotterill, Stephen; Deaton, A. Wayne
This paper describes the results of an integrated navigation and pointing system software development effort sponsored by the NASA MSFC through a SBIR Phase 2 Program. The integrated Global Positioning System (GPS)/Inertial Navigation System (INS) implements an autonomous navigation filter that is reconfigurable in real-time to accommodate mission contingencies. An onboard expert system monitors the spacecraft status and reconfigures the navigation filter accordingly, to optimize the system performance. The navigation filter is a multi-mode Kalman filter to estimate the spacecraft position, velocity, and attitude. Three different GPS-based attitude determination techniques, namely, velocity vector matching, attitude vector matching, and interferometric processing, are implemented to encompass different mission contingencies. The integrated GPS/INS navigation filter will use any of these techniques depending on the mission phase and the state of the sensors. The first technique, velocity vector matching, uses the GPS velocity measurement to estimate the INS velocity errors and exploits the correlation between INS velocity and attitude errors to estimate the attitude. The second technique, attitude vector matching, uses INS gyro measurements and GPS carrier phase (integrated Doppler) measurements during a spacecraft rotation maneuver to determine the attitude. Both of these techniques require only one GPS antenna onboard to determine the spacecraft attitude. The third technique, interferometric processing, requires use of multiple GPS antennae. In order to determine 3-axis body attitude, three GPS antennae (2 no-coplanor baselines) are required.
Modular Software for Spacecraft Navigation Using the Global Positioning System (GPS)
NASA Technical Reports Server (NTRS)
Truong, S. H.; Hartman, K. R.; Weidow, D. A.; Berry, D. L.; Oza, D. H.; Long, A. C.; Joyce, E.; Steger, W. L.
The Goddard Space Flight Center Flight Dynamics and Mission Operations Divisions have jointly investigated the feasibility of engineering modular Global Positioning SYSTEM (GPS) navigation software to support both real time flight and ground postprocessing configurations. The goals of this effort are to define standard GPS data interfaces and to engineer standard, reusable navigation software components that can be used to build a broad range of GPS navigation support applications. The paper discusses the GPS modular software (GMOD) system and operations concepts, major requirements, candidate software architecture, feasibility assessment and recommended software interface standards. In additon, ongoing efforts to broaden the scope of the initial study and to develop modular software to support autonomous navigation using GPS are addressed,
FPGA-based real-time embedded system for RISS/GPS integrated navigation.
Abdelfatah, Walid Farid; Georgy, Jacques; Iqbal, Umar; Noureldin, Aboelmagd
Navigation algorithms integrating measurements from multi-sensor systems overcome the problems that arise from using GPS navigation systems in standalone mode. Algorithms which integrate the data from 2D low-cost reduced inertial sensor system (RISS), consisting of a gyroscope and an odometer or wheel encoders, along with a GPS receiver via a Kalman filter has proved to be worthy in providing a consistent and more reliable navigation solution compared to standalone GPS receivers. It has been also shown to be beneficial, especially in GPS-denied environments such as urban canyons and tunnels. The main objective of this paper is to narrow the idea-to-implementation gap that follows the algorithm development by realizing a low-cost real-time embedded navigation system capable of computing the data-fused positioning solution. The role of the developed system is to synchronize the measurements from the three sensors, relative to the pulse per second signal generated from the GPS, after which the navigation algorithm is applied to the synchronized measurements to compute the navigation solution in real-time. Employing a customizable soft-core processor on an FPGA in the kernel of the navigation system, provided the flexibility for communicating with the various sensors and the computation capability required by the Kalman filter integration algorithm. PMID:22368460
FPGA-Based Real-Time Embedded System for RISS/GPS Integrated Navigation
Abdelfatah, Walid Farid; Georgy, Jacques; Iqbal, Umar; Noureldin, Aboelmagd
Navigation algorithms integrating measurements from multi-sensor systems overcome the problems that arise from using GPS navigation systems in standalone mode. Algorithms which integrate the data from 2D low-cost reduced inertial sensor system (RISS), consisting of a gyroscope and an odometer or wheel encoders, along with a GPS receiver via a Kalman filter has proved to be worthy in providing a consistent and more reliable navigation solution compared to standalone GPS receivers. It has been also shown to be beneficial, especially in GPS-denied environments such as urban canyons and tunnels. The main objective of this paper is to narrow the idea-to-implementation gap that follows the algorithm development by realizing a low-cost real-time embedded navigation system capable of computing the data-fused positioning solution. The role of the developed system is to synchronize the measurements from the three sensors, relative to the pulse per second signal generated from the GPS, after which the navigation algorithm is applied to the synchronized measurements to compute the navigation solution in real-time. Employing a customizable soft-core processor on an FPGA in the kernel of the navigation system, provided the flexibility for communicating with the various sensors and the computation capability required by the Kalman filter integration algorithm. PMID:22368460
Error Analysis System for Spacecraft Navigation Using the Global Positioning System (GPS)
NASA Technical Reports Server (NTRS)
Truong, S. H.; Hart, R. C.; Hartman, K. R.; Tomcsik, T. L.; Searl, J. E.; Bernstein, A.
The Flight Dynamics Division (FDD) at the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) is currently developing improved space-navigation filtering algorithms to use the Global Positioning System (GPS) for autonomous real-time onboard orbit determination. In connection with a GPS technology demonstration on the Small Satellite Technology Initiative (SSTI)/Lewis spacecraft, FDD analysts and programmers have teamed with the GSFC Guidance, Navigation, and Control Branch to develop the GPS Enhanced Orbit Determination Experiment (GEODE) system. The GEODE system consists of a Kalman filter operating as a navigation tool for estimating the position, velocity, and additional states required to accurately navigate the orbiting Lewis spacecraft by using astrodynamic modeling and GPS measurements from the receiver. A parallel effort at the FDD is the development of a GPS Error Analysis System (GEAS) that will be used to analyze and improve navigation filtering algorithms during development phases and during in-flight calibration. For GEAS, the Kalman filter theory is extended to estimate the errors in position, velocity, and other error states of interest. The estimation of errors in physical variables at regular intervals will allow the time, cause, and effect of navigation system weaknesses to be identified. In addition, by modeling a sufficient set of navigation system errors, a system failure that causes an observed error anomaly can be traced and accounted for. The GEAS software is formulated using Object Oriented Design (OOD) techniques implemented in the C++ programming language on a Sun SPARC workstation. The Phase 1 of this effort is the development of a basic system to be used to evaluate navigation algorithms implemented in the GEODE system. This paper presents the GEAS mathematical methodology, systems and operations concepts, and software design and implementation. Results from the use of the basic system to evaluate navigation algorithms implemented on GEODE are also discussed. In addition, recommendations for generalization of GEAS functions and for new techniques to optimize the accuracy and control of the GPS autonomous onboard navigation are presented.
A Self-Tuning Kalman Filter for Autonomous Navigation Using the Global Positioning System (GPS)
NASA Technical Reports Server (NTRS)
Truong, Son H.
Most navigation systems currently operated by NASA are ground-based, and require extensive support to produce accurate results. Recently developed systems that use Kalman filter and GPS (Global Positioning Systems) data for orbit determination greatly reduce dependency on ground support, and have potential to provide significant economies for NASA spacecraft navigation. These systems, however, still rely on manual tuning from analysts. A sophisticated neuro-fuzzy component fully integrated with the flight navigation system can perform the self-tuning capability for the Kalman filter and help the navigation system recover from estimation errors in real time.
An outdoor navigation system using GPS and inertial platform
S. Panzieri; F. Pascucci; G. Ulivi
The use of the Global Positioning System (GPS) in outdoor localization is a quite common solution in large environments where no other references are available and positioning requirements are not so pressing. Of course, fine motion without the use of an expensive differential device is not an easy task even now that available precision has been greatly improved as the
An outdoor navigation system using GPS and inertial platform
Stefano Panzieri; Federica Pascucci; Giovanni Ulivi
The use of global positioning system (GPS) in outdoor localization is quite a common solution in large environments where no other reference is available and there are not so demanding positioning requirements. Of course, fine motion without the use of an expensive differential device is not an easy task, even now that available precision has been greatly improved as the
A Self-Tuning Kalman Filter for Autonomous Navigation using the Global Positioning System (GPS)
NASA Technical Reports Server (NTRS)
Truong, S. H.
Most navigation systems currently operated by NASA are ground-based, and require extensive support to produce accurate results. Recently developed systems that use Kalman filter and GPS data for orbit determination greatly reduce dependency on ground support, and have potential to provide significant economies for NASA spacecraft navigation. These systems, however, still rely on manual tuning from analysts. A sophisticated neuro-fuzzy component fully integrated with the flight navigation system can perform the self-tuning capability for the Kalman filter and help the navigation system recover from estimation errors in real time.
Autonomous reconfigurable GPS/INS navigation and pointing system for rendezvous and docking
NASA Technical Reports Server (NTRS)
Upadhyay, Triveni M.
The briefing describes work using the Global Positioning System to determine position of spacecraft and the development of computer tools to utilize these position determinations to enable autonomous rendezvous. Using GPS data in conjunction with Inertial Navigation Systems (INS) provides the capability for absolute spacecraft navigation, navigation of one spacecraft relative to another, and attitude determination. Some results presented are based on limited observations, though simulation results are documented. A GPS/INS navigation flight experiment could provide a platform for evaluating approaches for autonomous operation and reconfigurability of the navigation and attitude determination subsystem for future space vehicles. Current emphasis is on the development and demonstration of an Onboard Mission Manager (OMM) and a Multi-Mode Navigation Kalman filter. Sensor data will be handed over to the OMM, which will determine the appropriate response and generate commands for the Kalman filter to use to reconfigure itself. Global Positioning System measurements and INS data will be processed in the integrated navigation filter and used to compute errors in position, velocity, and attitude. Inertial Navigation Systems instrument errors (biases, scale factors, etc.) also can be estimated. The OMM then will use a knowledge base to determine appropriate system response. The GPS is good for missions that have attitude pointing accuracy requirements within the 100 to 200 arcsecond range.
Land-vehicle navigation using GPS
The Global Positioning System (GPS) has made navigation systems practical for a number of land-vehicle navigation applications. Today, GPS-based navigation systems can be found in motor vehicles, farming and mining equipment, and a variety of other land-based vehicles (e.g., golf carts and mobile robots). Each of these applications is discussed and the reader is introduced to some of the issues
Space Shuttle Navigation in the GPS Era
NASA Technical Reports Server (NTRS)
Goodman, John L.
The Space Shuttle navigation architecture was originally designed in the 1970s. A variety of on-board and ground based navigation sensors and computers are used during the ascent, orbit coast, rendezvous, (including proximity operations and docking) and entry flight phases. With the advent of GPS navigation and tightly coupled GPS/INS Units employing strapdown sensors, opportunities to improve and streamline the Shuttle navigation process are being pursued. These improvements can potentially result in increased safety, reliability, and cost savings in maintenance through the replacement of older technologies and elimination of ground support systems (such as Tactical Air Control and Navigation (TACAN), Microwave Landing System (MLS) and ground radar). Selection and missionization of "off the shelf" GPS and GPS/INS units pose a unique challenge since the units in question were not originally designed for the Space Shuttle application. Various options for integrating GPS and GPS/INS units with the existing orbiter avionics system were considered in light of budget constraints, software quality concerns, and schedule limitations. An overview of Shuttle navigation methodology from 1981 to the present is given, along with how GPS and GPS/INS technology will change, or not change, the way Space Shuttle navigation is performed in the 21 5 century.
Autonomous Navigation of the SSTI/Lewis Spacecraft Using the Global Positioning System (GPS)
NASA Technical Reports Server (NTRS)
Hart, R. C.; Long, A. C.; Lee, T.
The National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD) is pursuing the application of Global Positioning System (GPS) technology to improve the accuracy and economy of spacecraft navigation. High-accuracy autonomous navigation algorithms are being flight qualified in conjunction with GSFC's GPS Attitude Determination Flyer (GADFLY) experiment on the Small Satellite Technology Initiative (SSTI) Lewis spacecraft, which is scheduled for launch in 1997. Preflight performance assessments indicate that these algorithms can provide a real-time total position accuracy of better than 10 meters (1 sigma) and velocity accuracy of better than 0.01 meter per second (1 sigma), with selective availability at typical levels. This accuracy is projected to improve to the 2-meter level if corrections to be provided by the GPS Wide Area Augmentation System (WAAS) are included.
Adaptive Resampling Particle Filters for GPS Carrier-Phase Navigation and Collision Avoidance System
NASA Astrophysics Data System (ADS)
Hwang, Soon Sik
This dissertation addresses three problems: 1) adaptive resampling technique (ART) for Particle Filters, 2) precise relative positioning using Global Positioning System (GPS) Carrier-Phase (CP) measurements applied to nonlinear integer resolution problem for GPS CP navigation using Particle Filters, and 3) collision detection system based on GPS CP broadcasts. First, Monte Carlo filters, called Particle Filters (PF), are widely used where the system is non-linear and non-Gaussian. In real-time applications, their estimation accuracies and efficiencies are significantly affected by the number of particles and the scheduling of relocating weights and samples, the so-called resampling step. In this dissertation, the appropriate number of particles is estimated adaptively such that the error of the sample mean and variance stay in bounds. These bounds are given by the confidence interval of a normal probability distribution for a multi-variate state. Two required number of samples maintaining the mean and variance error within the bounds are derived. The time of resampling is determined when the required sample number for the variance error crosses the required sample number for the mean error. Second, the PF using GPS CP measurements with adaptive resampling is applied to precise relative navigation between two GPS antennas. In order to make use of CP measurements for navigation, the unknown number of cycles between GPS antennas, the so called integer ambiguity, should be resolved. The PF is applied to this integer ambiguity resolution problem where the relative navigation states estimation involves nonlinear observations and nonlinear dynamics equation. Using the PF, the probability density function of the states is estimated by sampling from the position and velocity space and the integer ambiguities are resolved without using the usual hypothesis tests to search for the integer ambiguity. The ART manages the number of position samples and the frequency of the resampling step for real-time kinematics GPS navigation. The experimental results demonstrate the performance of the ART and the insensitivity of the proposed approach to GPS CP cycle-slips. Third, the GPS has great potential for the development of new collision avoidance systems and is being considered for the next generation Traffic alert and Collision Avoidance System (TCAS). The current TCAS equipment, is capable of broadcasting GPS code information to nearby airplanes, and also, the collision avoidance system using the navigation information based on GPS code has been studied by researchers. In this dissertation, the aircraft collision detection system using GPS CP information is addressed. The PF with position samples is employed for the CP based relative position estimation problem and the same algorithm can be used to determine the vehicle attitude if multiple GPS antennas are used. For a reliable and enhanced collision avoidance system, three dimensional trajectories are projected using the estimates of the relative position, velocity, and the attitude. It is shown that the performance of GPS CP based collision detecting algorithm meets the accuracy requirements for a precise approach of flight for auto landing with significantly less unnecessary collision false alarms and no miss alarms.
Development and Testing of a GPS-Augmented MultiSensor Vehicle Navigation System
J. Stephen; G. Lachapelle
An integrated multi-sensor vehicle navigation system is presented that uses a low-cost rate gyro and differential odometry to supplement GPS under signal masking conditions such as tree foliage and urban canyons. Signal masking is often accompanied by extreme multi-path in urban centres with tall buildings, and is also found in wooded areas, enclosed car parks, tunnels, etc. The purpose of
A step toward GPS\\/INS personal navigation systems: real-time assessment of gait by foot inertial sensing
Filippo Cavallo; Angelo M. Sabatini; Vincenzo Genovese
In this paper, we develop a system for which applications in the field of personal navigation are planned. In the current version, the system embodies a Global Positioning System (GPS) receiver and an inertial measurement unit (IMU), composed of two dual-axis accelerometers and one single-axis gyro. The IMU is positioned at a subject's foot instep, and it is intended to
Definition study of land/sea civil user navigational location monitoring systems for NAVSTAR GPS: User requirements and systems concepts
NASA Technical Reports Server (NTRS)
Devito, D. M.
A low-cost GPS civil-user mobile terminal whose purchase cost is substantially an order of magnitude less than estimates for the military counterpart is considered with focus on ground station requirements for position monitoring of civil users requiring this capability and the civil user navigation and location-monitoring requirements. Existing survey literature was examined to ascertain the potential users of a low-cost NAVSTAR receiver and to estimate their number, function, and accuracy requirements. System concepts are defined for low cost user equipments for in-situ navigation and the retransmission of low data rate positioning data via a geostationary satellite to a central computing facility.
Precise Real-Time Low-Earth-Orbiter Navigation With the Global Positioning System (GPS)
NASA Astrophysics Data System (ADS)
Bertiger, W.; Haines, B.; Kuang, D.; Lough, M.; Lichten, S.; Muellerschoen, R. J.; Vigue-Rodi, Y.; Wu, S.
Technology currently is available to support real-time onboard knowledge of the position of a low Earth orbiter at the 5- to 15-m level using the civilian broadcast Global Positioning System (GPS) signal with sophisticated models and filtering techniques onboard the spacecraft. Without these techniques, the standard positioning service yields 50 to 100 m with the current level of selective availability (SA). Proposed augmentations and/or enhancements to the GPS system will make rms accuracies of from 10 centimeters to a few decimeters available to the real-time onboard user. Presently, near-real-time processing of GPS tracking data can routinely provide low-Earth-orbit determination accuracy at the level of 5 cm. Such processing systems can, in fact, be fully automated; recent results from the Jet Propulsion Laboratory (JPL), where ongoing daily processing of low Earth GPS tracking data has been undertaken for several years, are presented in this article, showing orbit determination accuracies at the sub-10-cm level. At the present time, such solutions can be produced with about a 10-h delay after real time, but recent improvements in JPL's processing system soon will enable turnaround at the 1-h level or better for such precise orbit determination. We anticipate that orbit determination at the 1-cm-accuracy level will be demonstrated, with some refinements to the current system, in the not too distant future. Continuing enhancements in the automation of data retrieval and precise orbit processing will result in continuing decreases in latency for ground-based generation of precise orbit products for Earth orbiters. Such ephemerides can be propagated slightly ahead to provide real-time knowledge. However, there are advantages to an onboard, real-time orbit-determination capability. These include unique mission requirements (military, strategic, and scientific), as well as the potential to dramatically lower navigation operations costs through the enabling of a fully autonomous spacecraft. JPL has bee!n actively involved in the development of technology to enable a fully autonomous spacecraft in low Earth orbit. This article includes recent results of analysis of actual and simulated GPS data collected in space that demonstrate that a 10-cm (or better) real-time onboard orbit-determination capability presently is technologically feasible. In addition to space-based data, present-day tests in real time of wide-area differential GPS (WADGPS) on aircraft in real time show upper bounds for space-based users with a global WADGPS at the level of 30-cm-rms horizontal and 60-cm-rms vertical. The article describes several alternative technology road maps that can be followed to make such a capability routinely available to a wide range of low Earth orbiters. The discussion will include the use of wide-area approaches as well as non-WADGPS approaches for achieving this capability. In addition to supporting a sub-10-cm real-time onboard positioning capability in Earth orbit, this system also could support a few-decimeters real-time kinematic positioning for ground, sea, and air users globally.
X. Wang; C. Toth; D. Grejner-Brzezinska; H. Sun
GPS\\/INS integration can provide high accuracy (centimeter level) navigation under good satellite geometry and atmospheric conditions. However, due to GPS signal blockage and accumulative error attributes of INS, a GPS\\/INS system cannot continuously maintain such high accuracy navigation during GPS outages, which may frequently happen in terrestrial applications, such as when navigating in forested areas. Imaging sensors can provide adequate
Multiple mobile robot navigation using the indoor global positioning system (iGPS)
Yoshiro HADA; Kunikatsu TAKASE
We propose a practical method of multiple mobile robot navigation aimed at the realization of service robots that deliver letters, parcels and documents in an office building. For robust execution of delivery tasks by mobile robots, navigation is important, and localization of robots is a key function for designing robust navigation. We developed a global positioning system for indoor mobile
Abstract--There is an increasing demand for use of the Global Positioning System (GPS) to navigate or track objects in the
Washington at Seattle, University of
Abstract--There is an increasing demand for use of the Global Positioning System (GPS) to navigate--Forest, Global Positioning System, Image processing, Otsu' algorithm I. INTRODUCTION here is an increasing demand for use of the Global Positioning System (GPS) in the forest environment. For example, tree harvesters
GPS Navigation for Outdoor and Indoor Environments
Abidi, Mongi A.
of this would matter. #12;i ABSTRACT The Global Positioning System (GPS) is an accurate positioning system..................................................................................................... 1 2 GLOBAL POSITIONING SYSTEM OVERVIEW .............................................. 2 3 GPS
Evaluation of the impact of ionospheric disturbances on air navigation augmentation system using multi-point GPS receivers
NASA Astrophysics Data System (ADS)
Omatsu, N.; Otsuka, Y.; Shiokawa, K.; Saito, S.
In recent years, GPS has been utilized for navigation system for airplanes. Propagation delays in the ionosphere due to total electron content (TEC) between GPS satellite and receiver cause large positioning errors. In precision measurement using GPS, the ionospheric delay correction is generally conducted using both GPS L1 and L2 frequencies. However, L2 frequency is not internationally accepted as air navigation band, so it is not available for positioning directly in air navigation. In air navigation, not only positioning accuracy but safety is important, so augmentation systems are required to ensure the safety. Augmentation systems such as the satellite-based augmentation system (SBAS) or the ground-based augmentation system (GBAS) are being developed and some of them are already in operation. GBAS is available in a relatively narrow area around airports. In general, it corrects for the combined effects of multiple sources of positioning errors simultaneously, including satellite clock and orbital information errors, ionospheric delay errors, and tropospheric delay errors, using the differential corrections broadcast by GBAS ground station. However, if the spatial ionospheric delay gradient exists in the area, correction errors remain even after correction by GBAS. It must be a threat to GBAS. In this study, we use the GPS data provided by the Geographical Survey Institute in Japan. From the GPS data, TEC is obtained every 30 seconds. We select 4 observation points from 24.4 to 35.6 degrees north latitude in Japan, and analyze TEC data of these points from 2001 to 2011. Then we reveal dependences of Rate of TEC change Index (ROTI) on latitude, season, and solar activity statistically. ROTI is the root-mean-square deviation of time subtraction of TEC within 5 minutes. In the result, it is the midnight of the spring and the summer of the solar maximum in the point of 26.4 degrees north latitude that the value of ROTI becomes the largest. We think it is caused by plasma bubbles, and the maximum value of ROTI is about 6 TECU/min. Since it is thought that ROTI is an index representing the spatial ionospheric delay gradient, we can evaluate the effect of spatial ionospheric delay gradient to GBAS. In addition, we will discuss azimuth angle dependence of ROTI. We have found that ROTI tends to be high when the GPS satellites are seen westward. Initial analysis results in Indonesia show a similar feature. This feature could arise from the westward tilt of the plasma bubbles with altitude. More detailed results will be reported in this presentation.
Integrated navigation system and experiment of a low-cost and low-accuracy SINS\\/GPS
LIN Xueyuan XU; Jin Xu; Min Zhou
When SINS (strap-down inertial navigation system) is combined with GPS, the observability of the course angle is weak. Although\\u000a the course angle error is improved to some extent through Kalman filtering, the course angle still assumes a divergent trend.\\u000a This trend is aggravated further when using low-cost and low-accuracy SINS. In order to restrain this trend, a method that\\u000a uses
DARPA looks beyond GPS for positioning, navigating, and timing
Kramer, David
Cold-atom interferometry, microelectromechanical systems, signals of opportunity, and atomic clocks are some of the technologies the defense agency is pursuing to provide precise navigation when GPS is unavailable.
Position, Navigation, and Timing: GPS Scientific Applications
NASA Technical Reports Server (NTRS)
Neilan, Ruth E.
This slide presentation reviews the development and deployment of the Global Positioning System (GPS). This presentation also includes measuring space and time, GPS as a tool for science, development of high precision JPL GPS receivers, and technology and applications developments.
Research into navigation Algorithm for unmanned ground vehicle using Real Time Kinemtatic (RTK)GPS
Hoon-Je Woo; Bok-Joong Yoon; Bong-Geun Cho; Jung-Ha Kim
A navigation algorithm is very important on UGV. So, in this research, we propose the algorithm of navigation method by using RTK-GPS units and encoders. GPS systems sometimes lose their signals and receive inaccurate position data due to many factors, such as obstructions. This paper shows that GPS failure can be solved by using a DR navigation method with encoders
Next Generation GPS Ground Control Segment (OCX) Navigation Design
NASA Technical Reports Server (NTRS)
Bertiger, Willy; Bar-Sever, Yoaz; Harvey, Nate; Miller, Kevin; Romans, Larry; Weiss, Jan; Doyle, Larry; Solorzano, Tara; Petzinger, John; Stell, Al
In February 2010, a Raytheon-led team was selected by The Air Force to develop, implement, and operate the next generation GPS ground control segment (OCX). To meet and exceed the demanding OCX navigation performance requirements, the Raytheon team partnered with ITT (Navigation lead) and JPL to adapt major elements of JPL's navigation technology, proven in the operations of the Global Differential GPS (GDGPS) System. Key design goals for the navigation subsystem include accurate ephemeris and clock accuracy (user range error), ease of model upgrades, and a smooth and safe transition from the legacy system to OCX.We will describe key elements of the innovative architecture of the OCX navigation subsystem,and demonstrate the anticipated performance of the system through high fidelity simulations withactual GPS measurements.
Autonomous GPS/INS navigation experiment for Space Transfer Vehicle
NASA Technical Reports Server (NTRS)
Upadhyay, Triveni N.; Cotterill, Stephen; Deaton, A. W.
An experiment to validate the concept of developing an autonomous integrated spacecraft navigation system using on board Global Positioning System (GPS) and Inertial Navigation System (INS) measurements is described. The feasibility of integrating GPS measurements with INS measurements to provide a total improvement in spacecraft navigation performance, i.e. improvement in position, velocity and attitude information, was previously demonstrated. An important aspect of this research is the automatic real time reconfiguration capability of the system designed to respond to changes in a spacecraft mission under the control of an expert system.
Operational use of GPS navigation for space shuttle entry
John L. Goodman; Carolyn A. Propst
The STS-118 flight of the Space Shuttle Endeavour was the first shuttle mission flown with three Global Positioning System (GPS) receivers in place of the three legacy Tactical Air Navigation (TACAN) units. This marked the conclusion of a 15 year effort involving procurement, missionization, integration, and flight testing of a GPS receiver and a parallel effort to formulate and implement
Passive GPS-Free Navigation for Small UAVs
Jack Langelaan; Steve Rock
A method for passive GPS-free navigation of a small unmanned aerial vehicle with a minimal sensor suite (limited to an inertial measurement unit and a monocular camera) is presented. The navigation task is cast as a simultaneous localization and mapping (SLAM) problem. While SLAM has been the subject of a great deal of research, the highly non-linear system dynamics and
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.
Integrated INS/GPS Navigation from a Popular Perspective
NASA Technical Reports Server (NTRS)
Omerbashich, Mensur
Inertial navigation, blended with other navigation aids, Global Positioning System (GPS) in particular, has gained significance due to enhanced navigation and inertial reference performance and dissimilarity for fault tolerance and anti-jamming. Relatively new concepts based upon using Differential GPS (DGPS) blended with Inertial (and visual) Navigation Sensors (INS) offer the possibility of low cost, autonomous aircraft landing. The FAA has decided to implement the system in a sophisticated form as a new standard navigation tool during this decade. There have been a number of new inertial sensor concepts in the recent past that emphasize increased accuracy of INS/GPS versus INS and reliability of navigation, as well as lower size and weight, and higher power, fault tolerance, and long life. The principles of GPS are not discussed; rather the attention is directed towards general concepts and comparative advantages. A short introduction to the problems faced in kinematics is presented. The intention is to relate the basic principles of kinematics to probably the most used navigation method in the future-INS/GPS. An example of the airborne INS is presented, with emphasis on how it works. The discussion of the error types and sources in navigation, and of the role of filters in optimal estimation of the errors then follows. The main question this paper is trying to answer is 'What are the benefits of the integration of INS and GPS and how is this, navigation concept of the future achieved in reality?' The main goal is to communicate the idea about what stands behind a modern navigation method.
Evaluating the velocity accuracy of an integrated GPS/INS system: Flight test results. [Global positioning system/inertial navigation systems (GPS/INS)
Owen, T.E.; Wardlaw, R.
Verifying the velocity accuracy of a GPS receiver or an integrated GPS/INS system in a dynamic environment is a difficult proposition when many of the commonly used reference systems have velocity uncertainities of the same order of magnitude or greater than the GPS system. The results of flight tests aboard an aircraft in which multiple reference systems simultaneously collected data to evaluate the accuracy of an integrated GPS/INS system are reported. Emphasis is placed on obtaining high accuracy estimates of the velocity error of the integrated system in order to verify that velocity accuracy is maintained during both linear and circular trajectories. Three different reference systems operating in parallel during flight tests are used to independently determine the position and velocity of an aircraft in flight. They are a transponder/interrogator ranging system, a laser tracker, and GPS carrier phase processing. Results obtained from these reference systems are compared against each other and against an integrated real time differential based GPS/INS system to arrive at a set of conclusions about the accuracy of the integrated system.
Operational Use of GPS Navigation for Space Shuttle Entry
NASA Technical Reports Server (NTRS)
Goodman, John L.; Propst, Carolyn A.
The STS-118 flight of the Space Shuttle Endeavour was the first shuttle mission flown with three Global Positioning System (GPS) receivers in place of the three legacy Tactical Air Navigation (TACAN) units. This marked the conclusion of a 15 year effort involving procurement, missionization, integration, and flight testing of a GPS receiver and a parallel effort to formulate and implement shuttle computer software changes to support GPS. The use of GPS data from a single receiver in parallel with TACAN during entry was successfully demonstrated by the orbiters Discovery and Atlantis during four shuttle missions in 2006 and 2007. This provided the confidence needed before flying the first all GPS, no TACAN flight with Endeavour. A significant number of lessons were learned concerning the integration of a software intensive navigation unit into a legacy avionics system. These lessons have been taken into consideration during vehicle design by other flight programs, including the vehicle that will replace the Space Shuttle, Orion.
Airborne gravimetry, altimetry, and GPS navigation errors
NASA Technical Reports Server (NTRS)
Colombo, Oscar L.
Proper interpretation of airborne gravimetry and altimetry requires good knowledge of aircraft trajectory. Recent advances in precise navigation with differential GPS have made it possible to measure gravity from the air with accuracies of a few milligals, and to obtain altimeter profiles of terrain or sea surface correct to one decimeter. These developments are opening otherwise inaccessible regions to detailed geophysical mapping. Navigation with GPS presents some problems that grow worse with increasing distance from a fixed receiver: the effect of errors in tropospheric refraction correction, GPS ephemerides, and the coordinates of the fixed receivers. Ionospheric refraction and orbit error complicate ambiguity resolution. Optimal navigation should treat all error sources as unknowns, together with the instantaneous vehicle position. To do so, fast and reliable numerical techniques are needed: efficient and stable Kalman filter-smoother algorithms, together with data compression and, sometimes, the use of simplified dynamics.
NSDL National Science Digital Library
Leske, Cavin.
The Global Positioning System (GPS) has been in operation for several years, and its use is continually rising. GPS is the main satellite navigation system developed by the United States. There are countless applications of this technology, and numerous international efforts are currently underway.The Topcon Positioning Systems company provides an excellent introduction to GPS technology in its online book (1). The first couple chapters describe the evolution of GPS and its fundamentals, and the remaining material focuses on some specific issues. A more advanced tutorial is given through the IBM Web site (2). A brief, free registration is required to view it, and some familiarity with Java is recommended. The European Space Agency provides this page about satellite navigation (3), which describes, among other things, Galileo. This is not the astronomer; Galileo is Europe's version of GPS, scheduled for completion in 2008. Another system, developed by Russia, is detailed on the Space and Technology Web site (4). The short summary describes the 20-year history of the Global Navigation Satellite System (GLONASS), as well as upgrades that are in progress. Differential GPS, a service that is more accurate than standard GPS in areas with poor coverage, is operated by the US Coast Guard Navigation Center (5). Some information about the status of nationwide DGPS expansion is given. Several research and development projects, technology highlights, and GPS implementations are covered on the UNAVCO home page (6). The facility primarily fosters work to expand the applications of satellite navigation. With the wave of kidnapping cases reported across the country, a novel use of GPS is being marketed to keep track of children (7). These portable devices can be worn on the wrist, like a watch, so parents can always know where their kids are. Another news story describes the use of GPS in mining operations (8). The technology allows operators of huge three-story dump trucks to detect obstacles and maneuver the vehicle with only limited visibility.
Vibrotactile Feedback in Steering Wheel Reduces Navigation Errors during GPS-Guided Car Driving
Basdogan, Cagatay
Vibrotactile Feedback in Steering Wheel Reduces Navigation Errors during GPS-Guided Car Driving feedback displayed through the steering wheel of a car can reduce the perceptual and cognitive load with the GPS-based voice commands. KEYWORDS: vibrotactile, haptics, car navigation systems, GPS, steering wheel
Loosely Coupled GPS-Aided Inertial Navigation System for Range Safety
NASA Technical Reports Server (NTRS)
Heatwole, Scott; Lanzi, Raymond J.
The Autonomous Flight Safety System (AFSS) aims to replace the human element of range safety operations, as well as reduce reliance on expensive, downrange assets for launches of expendable launch vehicles (ELVs). The system consists of multiple navigation sensors and flight computers that provide a highly reliable platform. It is designed to ensure that single-event failures in a flight computer or sensor will not bring down the whole system. The flight computer uses a rules-based structure derived from range safety requirements to make decisions whether or not to destroy the rocket.
Autonomous Ground Vehicle Navigation Using Integrated GPS and Laser-scanner Measurements
Mathieu Joerger; Boris Pervan
This paper describes the design, analysis and testing of a navigation system based on combined GPS and laser-scanner measurements. Using carrier phase differential GPS, centimeter- level positioning of autonomous ground vehicles (AGVs) is achievable. However, GPS signals are easily attenuated or blocked, so their use is generally restricted to open-sky areas. In response, in this work we augment GPS with
Spacecraft orbit determination using GPS navigation solutions
Jae-Cheol Yoon; Byoung-Sun Lee; Kyu-Hong Choi
The orbit determination using the GPS navigation solutions for the KOMPSAT-1 spacecraft has been studied. The Cowell method of special perturbation theories was employed to develop a precision orbit propagation, and the perturbations due to geopotential, the gravity of the Sun and the Moon, solid Earth tides, ocean tides, the Earth's dynamic polar motion, solar radiation pressure, and atmospheric drag
GPS compound eye attitude and navigation sensor and method
NASA Technical Reports Server (NTRS)
Quinn, David A. (Inventor)
The present invention is a GPS system for navigation and attitude determination, comprising a sensor array including a convex hemispherical mounting structure having a plurality of mounting surfaces, and a plurality of antennas mounted to the mounting surfaces for receiving signals from space vehicles of a GPS constellation. The present invention also includes a receiver for collecting the signals and making navigation and attitude determinations. In an alternate embodiment the present invention may include two opposing convex hemispherical mounting structures, each of the mounting structures having a plurality of mounting surfaces, and a plurality of antennas mounted to the mounting surfaces.
GPS - Global Positioning System. Theory and practice
B. Hofmann-Wellenhof; H. Lichtenegger; J. Collins
This book shows in comprehensive manner how the Global Positioning System (GPS) works. The use of GPS for precise measurements (i.e. surveying) is treated as well as navigation and attitude determination. The basic mathematical models for various modes of GPS operations and detailed explanation of the practical use of GPS are developed precisely in this book. Additionally, the text shows
Satellite systems for maritime navigation
NASA Astrophysics Data System (ADS)
Bogdanov, Valerii Anatol'evich; Sorochinskii, Valentin Alekseevich; Iakshevich, Evgenii Viktorovich
The principles underlying the design of Doppler satellite navigation systems are examined, and the characteristics of existing and proposed satellite systems for maritime navigation are described. Particular attention is given to the COSPAS-SARSAT system, GPS/Navstar, and the Navsat, Granas, and Geostar projects. The features of shipboard navigation instruments are examined.
GPS Auto-Navigation Design for Unmanned Air Vehicles
NASA Technical Reports Server (NTRS)
Nilsson, Caroline C. A.; Heinzen, Stearns N.; Hall, Charles E., Jr.; Chokani, Ndaona
A GPS auto-navigation system is designed for Unmanned Air Vehicles. The objective is to enable the air vehicle to be used as a test-bed for novel flow control concepts. The navigation system uses pre-programmed GPS waypoints. The actual GPS position, heading, and velocity are collected by the flight computer, a PC104 system running in Real-Time Linux, and compared with the desired waypoint. The navigator then determines the necessity of a heading correction and outputs the correction in the form of a commanded bank angle, for a level coordinated turn, to the controller system. This controller system consists of 5 controller! (pitch rate PID, yaw damper, bank angle PID, velocity hold, and altitude hold) designed for a closed loop non-linear aircraft model with linear aerodynamic coefficients. The ability and accuracy of using GPS data, is validated by a GPS flight. The autopilots are also validated in flight. The autopilot unit flight validations show that the designed autopilots function as designed. The aircraft model, generated on Matlab SIMULINK is also enhanced by the flight data to accurately represent the actual aircraft.
Geomagnetic storms, super-storms, and their impacts on GPS-based navigation systems
NASA Astrophysics Data System (ADS)
Astafyeva, E.; Yasyukevich, Yu.; Maksikov, A.; Zhivetiev, I.
Using data of GPS receivers located worldwide, we analyze the quality of GPS performance during four geomagnetic storms of different intensity: two super-storms and two intense storms. We show that during super-storms the density of GPS Losses-of-Lock (LoL) increases up to 0.25% at L1 frequency and up to 3% at L2 frequency, and up to 0.15% (at L1) and 1% (at L2) during less intense storms. Also, depending on the intensity of the storm time ionospheric disturbances, the total number of total electron content (TEC) slips can exceed from 4 to 40 times the quiet time level. Both GPS LoL and TEC slips occur during abrupt changes of SYM-H index of geomagnetic activity, i.e., during the main phase of geomagnetic storms and during development of ionospheric storms. The main contribution in the total number of GPS LoL was found to be done by GPS sites located at low and high latitudes, whereas the area of numerous TEC slips seemed to mostly correspond to the boundary of the auroral oval, i.e., region with intensive ionospheric irregularities. Our global maps of TEC slips show where the regions with intense irregularities of electron density occur during geomagnetic storms and will let us in future predict appearance of GPS errors for geomagnetically disturbed conditions.
A GPS/Shuttle orbital navigation experiment
NASA Astrophysics Data System (ADS)
Peters, G.
A proposal is made to fly a Texas Instruments GPS geodetic receiver (GEOSTAR) on the Space Shuttle to evaluate its ability to perform autonomous orbit determination. GEOSTAR receiver and recorder units would be flown in the Shuttle's middeck for the purposes of computing real-time solutions and recording tracking data for post-flight analysis. Feasibility study results are presented which show that the GEOSTAR should be able to withstand flight induced loads, and to acquire and track GPS satellites in an orbital dynamic environment. Real-time navigation accuracies from 20 m to 400 m are anticipated.
Ready To Navigate: Classroom GPS Applications.
ERIC Educational Resources Information Center
Lucking, Robert A.; Christmann, Edwin P.
Discusses the potential contribution of GPS and related Geographic Information Systems (GIS) technology to education. Provides resources for teachers to plan a lesson on exploring with the help of a GPS device in order to increase students' awareness of their surroundings and broaden understanding of their place in the world. (KHR)
A low-cost hand-held GPS navigation system receiver
P. G. Mattos
In practice, it has been found that GPS service receivers cannot have an adequately accurate clock, satellite orbits are not adequately circular, and spherical intersections are not analytically soluble. The position calculation problem is presently approached by a method in which the major computational load is that of signal processing, rather than position-estimation; a high-speed general-purpose microprocessor is used to
U.S. Space Shuttle GPS navigation capability for all mission phases
NASA Astrophysics Data System (ADS)
Kachmar, Peter; Chu, William; Montez, Moises
Incorporating a GPS capability on the Space Shuttle presented unique system integration design considerations and has led to an integration concept that has minimum impact on the existing Shuttle hardware and software systems. This paper presents the Space Shuttle GPS integrated design and the concepts used in implementing this GPS capability. The major focus of the paper is on the modifications that will be made to the navigation systems in the Space Shuttle General Purpose Computers (GPC) and on the Operational Requirements of the integrated GPS/GPC system. Shuttle navigation system architecture, functions and operations are discussed for the current system and with the GPS integrated navigation capability. The GPS system integration design presented in this paper has been formally submitted to the Shuttle Avionics Software Control Board for implementation in the on-board GPC software.
Navigation Overview Types of Navigation
Navigation � Inertial Navigation System (INS) � Satellite Navigation Systems � Global Positioning System (GPS latitude, longitude, groundpseed, ..." � Accelerometers exhibit drift over time � Global Positioning System
X marks the spot, maybe [GPS navigation
E. A. Bretz
Navigation has long been considered an art form best practiced by experienced sailors. But today, thanks to the multitude of affordable, hand-held, Global Positioning System receivers on the market, almost anyone can be a navigational Magellan. The US Department of Defense (DOD) is at an advantage: it reserves for its own use the most accurate form of geolocation available, which
Anna Wu; Xiaolong Zhang; Wei Zhang
The proliferation of GPS units in our life has greatly changed how people find their ways in the real world. However, overreliance on step-by-step route directions from these automated navigation systems may result in less consciously building spatial knowledge of the environment, which is critical to wayfinding. Also, GPS devices may divert people's attention from objects in the physical world
Two-Filter Smoothing for Accurate INS\\/GPS Land-Vehicle Navigation in Urban Centers
Hang Liu; Sameh Nassar; Naser El-Sheimy
Currently, the concept of multisensor system integration is implemented in land-vehicle navigation (LVN) applications. The most common LVN multisensor configuration incorporates an integrated Inertial Navigation System\\/Global Positioning System (INS\\/GPS) system based on the Kalman filter (KF). For LVN, the demand is directed toward low-cost inertial sensors such as microelectromechanical systems (MEMS). Due to the combined problem of frequent GPS signal
GPS Navigation for the Magnetospheric Multi-Scale Mission
NASA Technical Reports Server (NTRS)
Bamford, William; Mitchell, Jason; Southward, Michael; Baldwin, Philip; Winternitz, Luke; Heckler, Gregory; Kurichh, Rishi; Sirotzky, Steve
In 2014. NASA is scheduled to launch the Magnetospheric Multiscale Mission (MMS), a four-satellite formation designed to monitor fluctuations in the Earth's magnetosphere. This mission has two planned phases with different orbits (1? x 12Re and 1.2 x 25Re) to allow for varying science regions of interest. To minimize ground resources and to mitigate the probability of collisions between formation members, an on-board orbit determination system consisting of a Global Positioning System (GPS) receiver and crosslink transceiver was desired. Candidate sensors would be required to acquire GPS signals both below and above the constellation while spinning at three revolutions-per-minute (RPM) and exchanging state and science information among the constellation. The Intersatellite Ranging and Alarm System (IRAS), developed by Goddard Space Flight Center (GSFC) was selected to meet this challenge. IRAS leverages the eight years of development GSFC has invested in the Navigator GPS receiver and its spacecraft communication expertise, culminating in a sensor capable of absolute and relative navigation as well as intersatellite communication. The Navigator is a state-of-the-art receiver designed to acquire and track weak GPS signals down to -147dBm. This innovation allows the receiver to track both the main lobe and the much weaker side lobe signals. The Navigator's four antenna inputs and 24 tracking channels, together with customized hardware and software, allow it to seamlessly maintain visibility while rotating. Additionally, an extended Kalman filter provides autonomous, near real-time, absolute state and time estimates. The Navigator made its maiden voyage on the Space Shuttle during the Hubble Servicing Mission, and is scheduled to fly on MMS as well as the Global Precipitation Measurement Mission (GPM). Additionally, Navigator's acquisition engine will be featured in the receiver being developed for the Orion vehicle. The crosslink transceiver is a 1/4 Watt transmitter utilizing a TDMA schedule to distribute a science quality message to all constellation members every ten seconds. Additionally the system generates one-way range measurements between formation members which is used as input to the Kalman filter. In preparation for the MMS Preliminary Design Review (PDR), the Navigator was required to pass a series of Technology Readiness Level (TRL) tests to earn the necessary TRL-6 classification. The TRL-6 level is achieved by demonstrating a prototype unit in a relevant end-to-end environment. The IRAS unit was able to meet all requirements during the testing phase, and has thus been TRL-6 qualified
A Comparative Study of Kalman Filter Implementations for Relative GPS Navigation�
Fritz, Matthew Peyton
filter used for relative GPS navigation. A spaceborne GPS model is developed to generate simulated GPS measurements for a spacecraft located on any orbit around the Earth below the GPS constellation. Position and velocity estimation algorithms for GPS...
Absolute and relative satellite-to-satellite navigation using GPS
NASA Astrophysics Data System (ADS)
Binning, Patrick William
This dissertation describes the methods and implementation of extended Kalman filtering, backwards smoothing and carrier phase integer ambiguity resolution for the problem of absolute satellite orbit determination and satellite to satellite relative navigation while using measurements from the Global Positioning System (GPS). All data are considered to be taken from both frequencies of the GPS constellation. Also, the data is considered to be free from the effects of Selective Availability (SA) although this feature is briefly addressed. The absolute navigation techniques are applied to actual data obtained from the TOPEX/Poseidon satellite as well as simulated data. The algorithms are used to estimate the position, velocity, clock offset, and frequency offset. The simulated data are derived from two sources: a software simulator, and a Northern Telecom GPS signal simulator used in conjunction with an Allen Osborne Associates TurboRogue receiver. Four algorithms are presented in the area of relative satellite to satellite navigation. These can be separated into two categories: those that base the relative state update using only the GPS pseudorange, and those that base the relative state update on the GPS carrier phase only. There are three pseudorange techniques investigated. The first involves straight differencing of two absolute estimates when using the pseudoranges from all observable GPS satellites from each receiver. The second involves using a correlated process noise matrix while processing simultaneous pseudoranges from common view GPS satellites. The relative state for this process is then the difference of the two absolute states. The measurements for both user spacecraft must be taken at the same instant in time for this process to work. A measurement interpolation algorithm is presented in order to solve this problem. The third pseudorange method is the first to estimate the relative state explicitly by employing the single difference pseudorange measurement. The carrier phase technique shows the highest accuracy for relative state estimation. The algorithm in this dissertation utilizes the widelane carrier phase combination of GPS observables. The single difference is then taken between two simultaneous widelane carrier phase measurements. Inherent in this process is the need to determine the widelane integer. A robust algorithm is presented which allows this problem to be solved. The relative navigation algorithms are applied to software and hardware simulated data. A unique aspect of this research involves using a Northern Telecom GPS RF signal generator with an Allen Osborne Associates TurboRogue receiver to simulate measurements from 2 coorbiting receivers. In addition, a software simulator is developed which allows more control over the simulation errors. The absolute navigation 1sigma position errors are 50 cm for a smoothed solution using precise GPS information and 3 to 7 meters when using the broadcast navigation parameters. The most precise pseudorange relative technique demonstrates 1sigma position errors of between 10 cm and 25 cm. The carrier phase technique shows 1sigma position errors on the order of 1.5 cm to 3.0 cm. These statistics are derived from 24 software simulations as well as 20 hardware simulations. A discussion of the cumulative results as well as individual test cases is presented.
76 FR 50808 - Airborne Supplemental Navigation Equipment Using the Global Positioning System (GPS)
Federal Register 2010, 2011, 2012, 2013, 2014
...Positioning System Augmented by the Satellite-Based Augmentation System...receiver to properly account for satellite range error if it is reflected...noise environment as other satellite systems become available...in new TSO-C129a product designs. Issued in Washington,...
Integrated GPS\\/INS navigation system design for autonomous spacecraft rendezvous
David Edward Gaylor
The goal of the NASA Space Launch Initiative (SLI) program is to advance the technologies for the next generation reusable launch vehicle (RLV). The SLI program has identified automated rendezvous and docking as an area requiring further research and development. Currently, the Space Shuttle uses a partially manual system for rendezvous, but a fully automated system could be safer and
Guarded Process Spaces (GPS): A Navigation System towards Creation and Dynamic Change of Healthcare
Pfeifer, Holger
independence. Keywords: Healthcare process, clinical pathway, process flexibility, domain specific languages 1, hospitals start with the introduction and deployment of standard processes (so called "clinical pathways. In principle, modern BPMSs (Business Process Management Systems) could help to support clinical pathways
Vehicular GPS Monitor System Based on GPRS Network
Ning tao
The new vehicular monitor system is combined with Global Positioning System (GPS) and general packet radio service (GPRS) by researching the GPS navigation technology and the shortcomings of current vehicular GPS monitor system. The design characteristics of vehicular GPS monitor system based on GPRS network are analyzed in the thesis.
Integration of Omega and satellite navigation systems
NASA Astrophysics Data System (ADS)
Schlachta, Henry B.
An extensive series of laboratory tests and flight trials has established that the hybrid Omega/VLF/GPS system effectively applies GPS to the enhancement of Omega with a cost-effective operator installation. The accuracy enhancement thus achieved also increases the reliability of navigation and furnishes aviation fuel savings superior to those of Omega, as a result of reduced flight-path wavering. The prospective GPS/GLONASS navigation system currently undergoing definition will be the first certifiable as a sole means on navigation; the Omega/VLF/GPS hybrid can serve as a transitional system.
A high integrity IMU\\/GPS navigation loop for autonomous land vehicle applications
Salah Sukkarieh; Eduardo M. Nebot; Hugh F. Durrant-Whyte
This paper describes the development and implementation of a high integrity navigation system, based on the combined use of the Global Positioning System (GPS) and an inertial measurement unit (IMU), for autonomous land vehicle applications. The paper focuses on the issue of achieving the integrity required of the navigation loop for use in autonomous systems. The paper highlights the detection
Perspective\\/navigation-The Global Positioning System
A brief history of navigation is given, highlighting the needs that led ultimately to the development of 3-D satellite based navigation. The evolution of Navstar, commonly known as GPS (Global Positioning System), is traced from its initial conception in 1960. The use of bandwidth compression to overcome the SNR problem is discussed. An explanation of how the GPS works is
Global Positioning System Tutorial: All About GPS
NSDL National Science Digital Library
The Global Positioning System (GPS) is a very popular and useful tool, whether you're navigating on a long hike or just driving through an unfamiliar town. A good tutorial that introduces the basics of the technology is found on the Web site of a leading GPS company, Trimble. It starts by describing the underlying concepts of GPS and how it compares to other positioning systems. Then, the principle of satellite triangulation is explained with as little technical jargon as possible. A large section of the tutorial covers differential GPS, a developing technology with profound implications. Lastly, some applications that use GPS are mentioned, and a glossary clarifies a few special terms.
Autonomous GPS/INS navigation experiment for Space Transfer Vehicle (STV)
NASA Technical Reports Server (NTRS)
Upadhyay, Triveni N.; Cotterill, Stephen; Deaton, A. Wayne
An experiment to validate the concept of developing an autonomous integrated spacecraft navigation system using on board Global Positioning System (GPS) and Inertial Navigation System (INS) measurements is described. The feasibility of integrating GPS measurements with INS measurements to provide a total improvement in spacecraft navigation performance, i.e. improvement in position, velocity and attitude information, was previously demonstrated. An important aspect of this research is the automatic real time reconfiguration capability of the system designed to respond to changes in a spacecraft mission under the control of an expert system.
Ultra-tightly Coupled GPS/Vehicle Sensor Integration for Land Vehicle Navigation
Calgary, University of
Ultra-tightly Coupled GPS/Vehicle Sensor Integration for Land Vehicle Navigation TAO LI, MARK G, and attitude information. This paper investigates an ultra-tight integration strategy to fuse GPS and a vehicle the fea- sibility of implementing the proposed system. Results demonstrate that the ultra-tight approach
Integrating GIS and GPS to realise autonomous navigation of farm machinery
Meng Xiangjian; Liu Gang
Path planning is a key technique to realise autonomous navigation of farm machines. Based on MapObjects, a Geographic Information System (GIS) for autonomous navigation was developed with Visual C++. A path search algorithm used to guide machines to track the desired path was designed. A Global Positioning System (GPS) was adopted in this algorithm to determine the current position of
Long-term evolution of navigation satellite orbits: GPS\\/GLONASS\\/GALILEO
C. C. Chao; R. A Gick
A recent study was performed to examine whether long-term growth in the eccentricity evolution exists for the disposal orbits of navigation satellite systems such as GPS, GLONASS, and GALILEO. Previous studies examined the orbit stability for GPS Block II satellites. The orbits of the non-operational GPS Block I satellites are included in this study because they are at 63.4� inclination,
Ship navigation using Navstar GPS - An application study
NASA Technical Reports Server (NTRS)
Mohan, S. N.
Ocean current measurement applications in physical oceanography require knowledge of inertial ship velocity to a precision of 1-2 cm/sec over a typical five minute averaging interval. The navigation accuracy must be commensurate with data precision obtainable from ship borne acoustic profilers used in sensing ocean currents. The Navstar Global Positioning System is viewed as a step in user technological simplification, extension in coverage availability, and enhancement in performance accuracy as well as reliability over the existing systems, namely, Loran-C, Transit, and Omega. Error analyses have shown the possibility of attaining the 1-2 cm/sec accuracy during active GPS coverage at a data rate of four position fixes per minute under varying sea-states. This paper is intended to present results of data validation exercises leading to design of an experiment at sea for deployment of both a GPS y-set and a direct Doppler measurement system as the autonomous navigation system used in conjunction with an acoustic Doppler as the sensor for ocean current measurement.
Decentralised approach to UAV navigation: without the use of GPS and preloaded maps
Jonghyuk Kim; Lee Ling; Eric Nettleton; Salah Sukkarieh
In this paper we address the issue of autonomous navigation, that is, the ability for a navigation system to provide information about the states of a vehicle without the need for a priori infrastructures such as GPS, beacons, or preloaded maps of the area of interest. The algorithm applied is known as Simultaneous Localisation and Mapping (SLAM). It is a
A Leo Satellite Navigation Algorithm Based on GPS and Magnetometer Data
NASA Technical Reports Server (NTRS)
Deutschmann, Julie; Harman, Rick; Bar-Itzhack, Itzhack
The Global Positioning System (GPS) has become a standard method for low cost onboard satellite orbit determination. The use of a GPS receiver as an attitude and rate sensor has also been developed in the recent past. Additionally, focus has been given to attitude and orbit estimation using the magnetometer, a low cost, reliable sensor. Combining measurements from both GPS and a magnetometer can provide a robust navigation system that takes advantage of the estimation qualities of both measurements. Ultimately, a low cost, accurate navigation system can result, potentially eliminating the need for more costly sensors, including gyroscopes. This work presents the development of a technique to eliminate numerical differentiation of the GPS phase measurements and also compares the use of one versus two GPS satellites.
Institute of Navigation GPS-99/Nashville/September 13-17, 1999 1 PSEUDOLITE-BASED INVERTED GPS
Calgary, University of
Institute of Navigation GPS-99/Nashville/September 13-17, 1999 1 PSEUDOLITE-BASED INVERTED GPS at the University of Calgary. She has been involved with GPS research since 1984 and has published numerous papers on static and kinematic GPS positioning. She is also the author of several GPS related software programs. Dr
Proceedings of NTM 2004 Conference (Session E3), San Diego, CA, January 26-28, The Institute of Navigation. 1 Kinematic Azimuth Alignment of INS using GPS
Calgary, University of
of Navigation. 1 Kinematic Azimuth Alignment of INS using GPS Velocity Information A. O. Salycheva and M is on the integration of GPS with medium accuracy inertial navigation systems. Dr. M. Elizabeth Cannon is Professor of Geomatics Engineering at the University of Calgary. She has been involved in GPS research and development
77 FR 16860 - Certain GPS Navigation Products, Components Thereof, and Related Software; Termination of...
Federal Register 2010, 2011, 2012, 2013, 2014
...TRADE COMMISSION [Investigation No. 337-TA-783] Certain GPS Navigation Products, Components Thereof, and Related Software...and sale within the United States after importation of certain GPS navigation products, components thereof, and related...
GPS Navigation Results from the Low Power Transceiver CANDOS Experiment on STS-107
NASA Technical Reports Server (NTRS)
Haas, Lin; Massey, Chris; Baraban, Dmitri; Kelbel, David; Lee, Taesul; Long, Anne; Carpenter, J. Russell
This paper presents the Global Positioning System (GPS) navigation results from the Communications and Savigation Demonstration on Shuttle (CANDOS) experiment flown on STS- 107. The CAkDOS experiment consisted of the Low Power Transceiver (LPT) that hosted the GPS Enhanced Orbit Determination Experiment (GEODE) orbit determination software. All CANDOS test data were recovered during the mission using the LPT's Tracking and Data Relay Satellite System (TDRSS) uplinh'downlink communications capabilit! . An overview of the LPT's navigation software and the GPS experiment timeline is presented. In addition. this paper discusses GEODE performance results. including comparisons ibith the Best Estimate of Trajectory (BET). N.ASA Johnson Space Center (JSC) real-time ground navigation vectors. and post-processed solutions using the Goddard Trajectory Determination System (GTDS).
GPSIM: A Personal Computer-Based GPS Simulator System
D. Ibrahim
Global Positioning Systems (GPS) are now in use in many applications, ranging from GIS to route guidance, automatic vehicle location (AVL), air, land, and marine navigation, and many other transportation and geographical based applications. In many applications, the GPS receiver is connected to some form of intelligent electronic system which receives the positional data from the GPS unit and then
Lightsey, Glenn
SPACECRAFT NAVIGATION USING THE MODERNIZED GLOBAL POSITIONING SYSTEM SIGNAL E. G. Lightsey and R. B The utility of the Global Positioning System (GPS) for spacecraft navigation and timing has been widely
Abstract--There is an increasing demand for use of the Global Positioning System (GPS) to navigate or track objects in the
Wang, Yinhai
1 Abstract--There is an increasing demand for use of the Global Positioning System (GPS--Forest, Global Positioning System, Image processing, Otsu' algorithm I. INTRODUCTION here is an increasing demand for use of the Global Positioning System (GPS) in the forest environment. For example, tree harvesters
GPS-based relative navigation for the Proba-3 formation flying mission
NASA Astrophysics Data System (ADS)
Ardaens, Jean-S�bastien; D'Amico, Simone; Cropp, Alexander
The primary objective of the Proba-3 mission is to build a solar coronagraph composed of two satellites flying in close formation on a high elliptical orbit and tightly controlled at apogee. Both spacecraft will embark a low-cost GPS receiver, originally designed for low-Earth orbits, to support the mission operations and planning during the perigee passage, when the GPS constellation is visible. The paper demonstrates the possibility of extending the utilization range of the GPS-based navigation system to serve as sensor for formation acquisition and coarse formation keeping. The results presented in the paper aim at achieving an unprecedented degree of realism using a high-fidelity simulation environment with hardware-in-the-loop capabilities. A modified version of the flight-proven PRISMA navigation system, composed of two single-frequency Phoenix GPS receivers and an advanced real-time onboard navigation filter, has been retained for this analysis. For several-day long simulations, the GPS receivers are replaced by software emulation to accelerate the simulation process. Special attention has been paid to the receiver link budget and to the selection of a proper attitude profile. Overall the paper demonstrates that, despite a limited GPS tracking time, the onboard navigation filter gets enough measurements to perform a relative orbit determination accurate at the centimeter level at perigee. Afterwards, the orbit prediction performance depends mainly on the quality of the onboard modeling of the differential solar radiation pressure acting on the satellites. When not taken into account, this perturbation is responsible for relative navigation errors at apogee up to 50 m. The errors can be reduced to only 10 m if the navigation filter is able to model this disturbance with 70% fidelity.
The ionosphere, radio navigation, and global navigation satellite systems
Paul M. Kintner; Brent M. Ledvina
This article is a review of Global Navigation Satellite Systems (GNSS) for space scientists who are interested in how GNSS signals and observables can be used to understand ionospheric dynamics and, conversely, how ionospheric dynamics affect the operational capabilities of GNSS receivers. The most common form of GNSS is the Global Positioning System (GPS); we will first review its operating
Non-GPS Navigation for Emergency Responders Lauro Ojeda and Johann Borenstein*
Borenstein, Johann
- This paper introduces a novel navigation system for walking persons. The system is of particular benefit of a walking person relative to a known starting position, such as the entrance to a building (POS) for measuring and tracking the momentary location and trajectory of a walking person, even if GPS
It's a long way to Monte Carlo: probabilistic display in GPS navigation
John Williamson; Steven Strachan; Roderick Murray-smith
We present a mobile, GPS-based multimodal navigation system, equipped with inertial control that allows users to explore and na- vigate through an augmented physical space, incorporating and displaying the uncertainty resulting from inaccurate sensing and unknown user intentions. The system propagates uncertainty ap- propriately via Monte Carlo sampling and predicts at a user- controllable time horizon. Control of the Monte
Integration of Omega and satellite navigation systems
Henry B. Schlachta
An extensive series of laboratory tests and flight trials has established that the hybrid Omega\\/VLF\\/GPS system effectively applies GPS to the enhancement of Omega with a cost-effective operator installation. The accuracy enhancement thus achieved also increases the reliability of navigation and furnishes aviation fuel savings superior to those of Omega, as a result of reduced flight-path wavering. The prospective GPS\\/GLONASS
Large magnetic storm-induced nighttime ionospheric flows at midlatitudes and their impacts on GPS-based navigation systems
Su. Basu; S. Basu; E. MacKenzie; P. Doherty; J. W. Wright; F. Rich; M. J. Keskinen; R. E. Sheehan
Analysis of GPS phase fluctuations in conjunction with regional total electron content (TEC) maps, in situ measurements of subauroral polarization streams (SAPS) and auroral convection from several Defense Meteorological Satellite Program spacecraft, and dynasonde measurements at the Bear Lake Observatory obtained during the intense magnetic storm of 7�8 November 2004 have indicated the serious impact of large ionospheric velocities on
Using GPS and GPS/INS Systems to Assess Relative Antenna Motion Onboard an Aircraft
Calgary, University of
Using GPS and GPS/INS Systems to Assess Relative Antenna Motion Onboard an Aircraft Carrier navigation systems for precise aircraft positioning. Dr. Cannon is a Past President of the ION. ABSTRACT provide auto-landing capability for an inbound aircraft. An inherent requirement therefore is to know
Development of a Frequency Dependent INS\\/GPS System Response Model for Bridging GPS Outages
M. El-Diasty; S. Pagiatakis
The integration of Inertial Navigation System (INS) and Global Positioning System (GPS) architectures can be achieved through the use of many time domain filters such as, an extended Kalman filter, an unscented Kalman filter, divided difference filter, and particle filter. The main objective of all the above filters is to achieve precise fusion of the data from GPS and INS
Low Earth orbit satellite navigation errors and vertical total electron content in single-frequency GPS tracking
Miquel Garcia-Fern�ndez; Oliver Montenbruck
In the context of space applications, the GPS system is presently a well-established and accepted tracking system. To meet the basic navigation requirements, most satellites in a low Earth orbit are equipped with single-frequency GPS receivers that measure the coarse acquisition code as well as the L1 phase. However, the resulting kinematic navigation solutions exhibit systematic position errors caused by
Global Navigation Satellite Systems (GNSSs) for Monitoring Long Suspension Bridges
Santerre, Rock
, Nanjing, China 1 A Brief Introduction to the Global Positioning System 1 2 GPS for Structural Health 16 1 A BRIEF INTRODUCTION TO THE GLOBAL POSITIONING SYSTEM 1.1 GPS constellation The full term of the well-known acronym GPS is NAVSTAR global positioning system, where NAVSTAR stands for NAVigation System
Results from Navigator GPS Flight Testing for the Magnetospheric MultiScale Mission
NASA Technical Reports Server (NTRS)
Lulich, Tyler D.; Bamford, William A.; Wintermitz, Luke M. B.; Price, Samuel R.
The recent delivery of the first Goddard Space Flight Center (GSFC) Navigator Global Positioning System (GPS) receivers to the Magnetospheric MultiScale (MMS) mission spacecraft is a high water mark crowning a decade of research and development in high-altitude space-based GPS. Preceding MMS delivery, the engineering team had developed receivers to support multiple missions and mission studies, such as Low Earth Orbit (LEO) navigation for the Global Precipitation Mission (GPM), above the constellation navigation for the Geostationary Operational Environmental Satellite (GOES) proof-of-concept studies, cis-Lunar navigation with rapid re-acquisition during re-entry for the Orion Project and an orbital demonstration on the Space Shuttle during the Hubble Servicing Mission (HSM-4).
Navigation and slope detection system design for autonomous mobile robot
Boyu Wei; Junyao Gao; Kejie Li; Hu Chen
Autonomous mobile robot navigation is a hot research field in recent years. We design a four-tracked autonomous mobile robot with a main-controller based on ARM s3c2410 and sub-controller based on ATmega128. The navigation system consists of GPS, INS, ultrasonic and infrared sensors. The used of the GPS and inertial navigation system for autonomous mobile robot makes its navigation precision and
Development And Test of A Digitally Steered Antenna Array for The Navigator GPS Receiver
NASA Technical Reports Server (NTRS)
Pinto, Heitor David; Valdez, Jennifer E.; Winternitz, Luke M. B.; Hassouneh, Munther A.; Price, Samuel R.
Global Positioning System (GPS)-based navigation has become common for low-Earth orbit spacecraft as the signal environment is similar to that on the Earth s surface. The situation changes abruptly, however, for spacecraft whose orbital altitudes exceed that of the GPS constellation. Visibility is dramatically reduced and signals that are present may be very weak and more susceptible to interference. GPS receivers effective at these altitudes require increased sensitivity, which often requires a high-gain antenna. Pointing such an antenna can pose a challenge. One efficient approach to mitigate these problems is the use of a digitally steered antenna array. Such an antenna can optimally allocate gain toward desired signal sources and away from interferers. This paper presents preliminary results in the development and test of a digitally steered antenna array for the Navigator GPS research program at NASA s Goddard Space Flight Center. In particular, this paper highlights the development of an array and front-end electronics, the development and test of a real-time software GPS receiver, and implementation of three beamforming methods for combining the signals from the array. Additionally, this paper discusses the development of a GPS signal simulator which produces digital samples of the GPS L1C/A signals as they would be received by an arbitrary antenna array configuration. The simulator models transmitter and receiver dynamics, near-far and multipath interference, and has been a critical component in both the development and test of the GPS receiver. The GPS receiver system was tested with real and simulated GPS signals. Preliminary results show that performance improvement was achieved in both the weak signal and interference environments, matching analytical predictions. This paper summarizes our initial findings and discusses the advantages and limitations of the antenna array and the various beamforming methods.
Benefits of Combined GPS/GLONASS with Low-Cost MEMS IMUs for Vehicular Urban Navigation
Angrisano, Antonio; Petovello, Mark; Pugliano, Giovanni
The integration of Global Navigation Satellite Systems (GNSS) with Inertial Navigation Systems (INS) has been very actively researched for many years due to the complementary nature of the two systems. In particular, during the last few years the integration with micro-electromechanical system (MEMS) inertial measurement units (IMUs) has been investigated. In fact, recent advances in MEMS technology have made possible the development of a new generation of low cost inertial sensors characterized by small size and light weight, which represents an attractive option for mass-market applications such as vehicular and pedestrian navigation. However, whereas there has been much interest in the integration of GPS with a MEMS-based INS, few research studies have been conducted on expanding this application to the revitalized GLONASS system. This paper looks at the benefits of adding GLONASS to existing GPS/INS(MEMS) systems using loose and tight integration strategies. The relative benefits of various constraints are also assessed. Results show that when satellite visibility is poor (approximately 50% solution availability) the benefits of GLONASS are only seen with tight integration algorithms. For more benign environments, a loosely coupled GPS/GLONASS/INS system offers performance comparable to that of a tightly coupled GPS/INS system, but with reduced complexity and development time. PMID:22666079
A LEO Satellite Navigation Algorithm Based on GPS and Magnetometer Data
NASA Technical Reports Server (NTRS)
Deutschmann, Julie; Bar-Itzhack, Itzhack Y.; Harman, Rick
The Global Position System (GPS) has become a standard method for low cost onboard satellite orbit determination. The use of GPS as an attitude and rate sensor has also been developed in the recent past. Additionally, focus has been given to attitude and orbit estimation using the magnetometer, a low cost, reliable sensor. Combining measurements from both GPS and a magnetometer can provide a robust navigation system which takes advantage of the estimation qualities of both measurements. Ultimately a low cost, accurate navigation system can result, potentially eliminating the need for more costly sensors, including gyroscopes. This work presents the development and preliminary testing of a unified navigation algorithm which produces estimates of attitude, angular rate, position, and velocity for a low earth orbit (LEO) spacecraft. The system relies on GPS phase, range, and range rate data as well as magnetometer data. The algorithm used is an extended Kalman filter (EKF) developed to provide LEO attitude, orbit, and rate estimates using magnetometer and sun sensor data. Incorporating sun sensor data into the EKF improved the attitude and rate estimates. For many LEO spacecraft the sun data is available during only a portion of the orbit. However, GPS data is available continuously throughout the orbit. GPS can produce accurate orbit estimates and combining GPS and magnetometer data improves the attitude and rate estimates. The magnetometer based EKF can converge from large initial errors in position, velocity, and 3 attitude . Combining the magnetometer and GPS data into a single EKF will provide a more robust and accurate system. The EKF is based on an existing EKF. The GPS measurement models for phase, range, and range rate are incorporated into the existing structure of the filter. The original EKF produced the orbit estimates in terms of Keplerian elements. Due to the nature of the GPS measurements and ease of computation, the orbit estimates are converted to the Cartesian position and velocity. The measurement model for the magnetometer is adjusted for this change in the state and the measurements. Preliminary test results based on simulated GPS and magnetometer data are included.
Meta-image navigation augmenters for GPS denied mountain navigation of small UAS
NASA Astrophysics Data System (ADS)
Wang, Teng; ?elik, Koray; Somani, Arun K.
We present a novel approach to use mountain drainage patterns for GPS-Denied navigation of small unmanned aerial systems (UAS) such as the ScanEagle, utilizing a down-looking fixed focus monocular imager. Our proposal allows extension of missions to GPS-denied mountain areas, with no assumption of human-made geographic objects. We leverage the analogy between mountain drainage patterns, human arteriograms, and human fingerprints, to match local drainage patterns to Graphics Processing Unit (GPU) rendered parallax occlusion maps of geo-registered radar returns (GRRR). Details of our actual GPU algorithm is beyond the subject of this paper, and is planned as a future paper. The matching occurs in real-time, while GRRR data is loaded on-board the aircraft pre-mission, so as not to require a scanning aperture radar during the mission. For recognition purposes, we represent a given mountain area with a set of spatially distributed mountain minutiae, i.e., details found in the drainage patterns, so that conventional minutiae-based fingerprint matching approaches can be used to match real-time camera image against template images in the training set. We use medical arteriography processing techniques to extract the patterns. The minutiae-based representation of mountains is achieved by first exposing mountain ridges and valleys with a series of filters and then extracting mountain minutiae from these ridges/valleys. Our results are experimentally validated on actual terrain data and show the effectiveness of minutiae-based mountain representation method. Furthermore, we study how to select landmarks for UAS navigation based on the proposed mountain representation and give a set of examples to show its feasibility. This research was in part funded by Rockwell Collins Inc.
GPS Receiver Architecture and Expected Performance for Autonomous Navigation in High Earth Orbits
GPS is an enabling technology for autonomous spacecraft navigation, including mission concepts involving formation flying in highly eccentric orbits. However, to date most spaceborne GPS applications have been limited to low earth orbits or postprocessing applications. This paper describes the problems associated with () using GPS in the high earth orbit HEO environment and presents a GPS receiver design optimized
Robust Real-Time Wide-Area Differential GPS Navigation
NASA Technical Reports Server (NTRS)
Yunck, Thomas P. (Inventor); Bertiger, William I. (Inventor); Lichten, Stephen M. (Inventor); Mannucci, Anthony J. (Inventor); Muellerschoen, Ronald J. (Inventor); Wu, Sien-Chong (Inventor)
The present invention provides a method and a device for providing superior differential GPS positioning data. The system includes a group of GPS receiving ground stations covering a wide area of the Earth's surface. Unlike other differential GPS systems wherein the known position of each ground station is used to geometrically compute an ephemeris for each GPS satellite. the present system utilizes real-time computation of satellite orbits based on GPS data received from fixed ground stations through a Kalman-type filter/smoother whose output adjusts a real-time orbital model. ne orbital model produces and outputs orbital corrections allowing satellite ephemerides to be known with considerable greater accuracy than from die GPS system broadcasts. The modeled orbits are propagated ahead in time and differenced with actual pseudorange data to compute clock offsets at rapid intervals to compensate for SA clock dither. The orbital and dock calculations are based on dual frequency GPS data which allow computation of estimated signal delay at each ionospheric point. These delay data are used in real-time to construct and update an ionospheric shell map of total electron content which is output as part of the orbital correction data. thereby allowing single frequency users to estimate ionospheric delay with an accuracy approaching that of dual frequency users.
Navigation and Attitude Estimation from GPS Pseudorange, Carrier Phase and dopples Observables
NASA Astrophysics Data System (ADS)
Vieira, D.
This paper describes a procedure for navigation solution and attitude determination based on GPS observables only. The algorithm is supposed to be a contribution to the INPE's development project of a GPS receiver and antennas for space applications. Usually, the subjects of GPS-based navigation solution and attitude determination have been addressed separately. Several algorithms have been presented for navigation fix, velocity determination, orbit determination and attitude determination. In some cases the algorithms are based on the pseudoranges alone while in other cases the Doppler is used or the carrier phase. Also, there are a number of algorithms integrating inertial sensors with GPS in order to improve the dynamical model, especially in applications where GPS signal outages are likely to happen. The proposed procedure estimates the satellite position, velocity, attitude and angular rate from all pseudorange C/A, carrier phase L1 and Doppler D1 observables from multiple antennas. One considers a class of applications including, but not restricted to, Earth stabilized LEO satellites. In this case, the visibility condition is stable and allows continuous locking of several GPS satellites simultaneously, even in polar latitudes. Furthermore, the dynamics of a three-axis stabilized satellite is quite smooth. One takes advantage from the redundant information on the GPS observables to eliminate the need of inertial sensors or any sophisticate dynamical model, by means of dynamic compensation of non-modeled accelerations. Local, least squares estimates from the GPS observables are taken as state observations for a Kalman filter. Both observation errors and dynamic noise are modeled as locally stationary, first order Markovian processes with correlation time constant and noise intensity empirically adjusted by a technique based on the mean time between signal inversions. The algorithm was tested with simulated data and the Kalman filter converged to a steady-state accuracy level considerably better than the one given by the local estimates. Preliminary results using real data taken from a ground experiment with a Beeline GPS receiver indicates that the algorithm is promising and should be considered for use in the integrated navigation and attitude system by GPS being currently developed at INPE.
Applications of Clocks to Space Navigation & "Planetary GPS"
NASA Technical Reports Server (NTRS)
Lichten, Stephen M.
The ability to fly atomic clocks on GPS satellites has profoundly defined the capabilities and limitations of GPS in near-Earth applications. It is likely that future infrastructure for Lunar and Mars applications will be constrained by financial factors. The development of a low cost, small, high performance space clock -- or ultrahigh performance space clocks -- could revolutionize and drive the entire approach to GPS-like systems at the Moon (or Mars), and possibly even change the future of GPS at Earth. Many system trade studies are required. The performance of future GPS-like tracking systems at the Moon or Mars will depend critically on clock performance, availability of inertial sensors, and constellation coverage. Example: present-day GPS carry 10(exp -13) clocks and require several updates per day. With 10(exp -15) clocks, a constellation at Mars could operate autonomously with updates just once per month. Use of GPS tracking at the Moon should be evaluated in a technical study.
Institute of Navigation National Technical Meeting/Anaheim, CA/January 26-28,2000 1 Analysis of Multiple GPS Antennas for
Calgary, University of
based on statistical reliability testing is presented. INTRODUCTION The Global Positioning System (GPS of Multiple GPS Antennas for Multipath Mitigation in Vehicular Navigation R. A. Nayak, M. E. Cannon Department, India. He has been involved in GPS research since 1994 in the area of receiver hardware and software
Networked differential GPS system
NASA Technical Reports Server (NTRS)
Mueller, K. Tysen (Inventor); Loomis, Peter V. W. (Inventor); Kalafus, Rudolph M. (Inventor); Sheynblat, Leonid (Inventor)
An embodiment of the present invention relates to a worldwide network of differential GPS reference stations (NDGPS) that continually track the entire GPS satellite constellation and provide interpolations of reference station corrections tailored for particular user locations between the reference stations Each reference station takes real-time ionospheric measurements with codeless cross-correlating dual-frequency carrier GPS receivers and computes real-time orbit ephemerides independently. An absolute pseudorange correction (PRC) is defined for each satellite as a function of a particular user's location. A map of the function is constructed, with iso-PRC contours. The network measures the PRCs at a few points, so-called reference stations and constructs an iso-PRC map for each satellite. Corrections are interpolated for each user's site on a subscription basis. The data bandwidths are kept to a minimum by transmitting information that cannot be obtained directly by the user and by updating information by classes and according to how quickly each class of data goes stale given the realities of the GPS system. Sub-decimeter-level kinematic accuracy over a given area is accomplished by establishing a mini-fiducial network.
Testing the Preliminary X-33 Navigation System
NASA Technical Reports Server (NTRS)
Lomas, James J.; Mitchell, Daniel W.; Freestone, Todd M.; Lee, Charles; Lessman, Craig; Foster, Lee D. (Technical Monitor)
The X-33 Reusable Launch Vehicle (RLV) must meet the demanding requirements of landing autonomously on a narrow landing strip following a flight that reaches an altitude of up to 200,000 feet and a speed in excess of Mach 9 with significant in-flight energy bleed-off maneuvers. To execute this flight regimen a highly reliable avionics system has been designed that includes three LN-100G Inertial Navigation System/Global Positioning System (INS/GPS) units as the primary navigation system for the X-33. NASA's Marshall Space Flight Center (MSFC) tested an INS/GPS system in real-time simulations to determine the ability of this navigation suite to meet the in flight and autonomous landing requirements of the X-33 RLV. A total of sixty-one open loop tests were performed to characterize the navigation accuracy of the LN-100G. Twenty-seven closed-loop tests were also performed to evaluate the performance of the X-33 Guidance, Navigation and Control (GN&C) algorithms with the real navigation hardware. These closed-loop tests were also designed to expose any integration or operational issues with the real-time X-33 vehicle simulation. Dynamic road tests of the INS/GPS were conducted by Litton to assess the performance of differential and nondifferential INS/GPS hybrid navigation solutions. The results of the simulations and road testing demonstrate that this novel solution is capable of meeting the demanding requirements of take-off, in-flight navigation, and autonomous landing of the X-33 RLV. This paper describes the test environment developed to stimulate the LN-100G and discusses the results of this test effort. This paper also presents recommendations for a navigation system suitable to an operational RLV system.
Development of a Frequency Dependent INS/GPS System Response Model for Bridging GPS Outages
NASA Astrophysics Data System (ADS)
El-Diasty, M.; Pagiatakis, S.
The integration of Inertial Navigation System (INS) and Global Positioning System (GPS) architectures can be achieved through the use of many time domain filters such as, an extended Kalman filter, an unscented Kalman filter, divided difference filter, and particle filter. The main objective of all the above filters is to achieve precise fusion of the data from GPS and INS to provide INS only navigation solution during GPS outages. The prediction mode performance of all state of the art time domain filters is poor with significant drift in the INS only solution. In this paper, a new frequency domain dynamic response method with variable frequency bandwidth is proposed to model the INS/GPS system. The Least Squares Spectral Analysis (LSSA), Parzen window based smoothing, and the Inverse Least Squares Fourier Transform (ILSFT) are employed to develop the INS/GPS system frequency response (transfer function). The input to this dynamic system is the INS only solution and the output is the INS/GPS integration solution. The discrete inverse ILSFT of the transfer function is applied to estimate the impulse response of the INS/GPS system. The focus of this paper is the improvement in velocity solution, which leads to almost the same level of improvement in the position solution in an INS/GPS system. To examine the performance of the proposed approach, a kinematic dataset (Dual frequency GPS data from a Trimble BD950 receiver and inertial data from DQI100 IMU) is collected in Hamilton Harbour, Ontario, onboard a hydrographic surveying vessel owned by the Canadian Hydrographic Service. The loosely coupled INS/GPS with unscented Kalman filter is developed to obtain an INS/GPS integrated navigation solution and an INS only solution. Then, the INS/GPS and INS only navigation solutions are used to develop the impulse response of the INS/GPS system. It is shown that the developed impulse response can be used to detect and recover the long term motion dynamics of DQI100 IMU during 300s GPS outages with about 65% dynamic recovery of the north velocity and 45% dynamic recovery of east velocity solution when compared with the INS only solution. We will present and discuss many examples from a variety of GPS outages that exemplify the effectiveness of our method.
Conceptual deliberations on the global use of satellite navigation systems
NASA Astrophysics Data System (ADS)
Hartl, Ph.
The increase in demand for navigation services worldwide is reviewed, and the use of satellite navigation systems to help satisfy navigation-related needs is discussed. The applications and availabiilty of GPS are addressed, and the roles of the FAA National Airspace System, Glonass, Inmarsat, Geostar/Locstar are described.
Testing Microwave Landing Systems With Satellite Navigation
NASA Technical Reports Server (NTRS)
Kiriazes, John J.
Less time and equipment needed to perform tests. Satellite-based Global Positioning System (GPS) measures accuracy of microwave scanning-beam landing system (MSBLS) at airports used to support Shuttle landings. Provides time and three-dimensional information on position and velocity with unprecedented accuracy. Useful for testing other electronic navigation aids like LORAN, TACAN and microwave landing systems (MLS).
Simulation of a navigator algorithm for a low-cost GPS receiver
NASA Technical Reports Server (NTRS)
Hodge, W. F.
The analytical structure of an existing navigator algorithm for a low cost global positioning system receiver is described in detail to facilitate its implementation on in-house digital computers and real-time simulators. The material presented includes a simulation of GPS pseudorange measurements, based on a two-body representation of the NAVSTAR spacecraft orbits, and a four component model of the receiver bias errors. A simpler test for loss of pseudorange measurements due to spacecraft shielding is also noted.
Electric compass aided global positioning system navigation for powered wheelchairs.
Chien, Jen-Chien; Lu, Bing-Yuh; Lai, Jin-Shin; Luh, Jerjunn; Chong, Fok-Ching; Kuo, Te-Son
Powered wheelchairs are an important mobility aid for the elderly and for persons with disability. According to World Health Organization statistics, most of the accidents were due to personal mistakes; if there is an auto-navigating system such as auxiliary, mistaken manipulation will decrease efficiency. This study attempted to improve the global positioning system (GPS) navigation of electric powered wheelchairs (EPWs) through the addition of an electric compass (EC) and tested the navigation of EPWs with EC-aided and non-EC-aided GPS navigation along a 25 m road. According to these tests, the use of the EC significantly reduces the errors in GPS navigation during movements such as go straight ahead, turn right and turn left. Therefore, the navigation reduced the error of the expected trajectories with the EC-aided navigation. PMID:20415531
GPS(global positioning system) , , . D. Patterson GPS(Global Positioning
Cho, Sung-Bae
. . . GPS(global positioning system) , , , , [1]. , . . . . D. Patterson GPS(Global Positioning System) GPS [2]. D. Ashbrook GPS k-means [3]. . . GPS . GPS 10m . SOM(self-organizing map) . SOM GPS . . 1 . , . RSOM(recurrent SOM) . SOM . RSOM SOM [4]. SOM . GPS . #12;GPS Sensor Train SOM Build Local
Matching Raw GPS Measurements on a Navigable Map Without Computing a Global Position
Paris-Sud XI, Université de
1 Matching Raw GPS Measurements on a Navigable Map Without Computing a Global Position Clément with respect to a road network description stored in a digital map. This problem is usually addressed using GPS because of outages due to tall buildings. In this paper, map-matching is solved using raw GPS measurements
GpsTunes: controlling navigation via audio feedback
Steven Strachan; Parisa Eslambolchilar; Roderick Murray-Smith; Stephen Hughes; Sile O'Modhrain
We combine the functionality of a mobile Global Positioning System (GPS) with that of an MP3 player, implemented on a PocketPC, to produce a handheld system capable of guiding a user to their desired target location via continuously adapted music feedback. We illustrate how the approach to presentation of the audio display can benefit from insights from control theory, such
Regional Navigation System Using Geosynchronous Satellites and Stratospheric Airships
Won, Chang-Hee
he or she is at. Now the Global Positioning System (GPS) provides the ultimate solution is possible. Because there already exists a fully functional global positioning system (i.e., GPS), we propose navigation using just this augmented system without the aid of the existing global positioning system
The effectiveness of global positioning system electronic navigation
M. Wright; D. Stallings; D. Dunn
Global Positioning System (GPS) is a worldwide radio-navigation system that consists of a constellation of twenty-four satellites located in six orbits, and their ground control stations. A unique device called the GPS receiver is responsible for the actual interface between the civil user and the global positioning system network. Global position system provides specially coded satellite signals that can be
Introduction to Global Navigation Satellite System
NASA Technical Reports Server (NTRS)
Moreau, Michael
This viewgraph presentation reviews the fundamentals of satellite navigation, and specifically how GPS works. It presents an overview and status of Global Positioning System, for both the current GPS, and plans to modernize it in the future. There is also a overview and status of other Global Navigation Satellite System (GNSS), specifically GLONASS, Galileo, and QZSS. There is also a review of Satellite based time transfer techniques. The topic is of interest to the Time and Frequency Community, because the Global Positioning system has become the primary system for distributing Time and frequency globally, and because it allows users to synchronize clocks and calibrate and control oscillators in any location that has a GPS antenna.
In-car gps navigation: engagement with and disengagement from the environment
Gilly Leshed; Theresa Velden; Oya Rieger; Blazej J. Kot; Phoebe Sengers
Although in-car GPS navigation technology is proliferating, it is not well understood how its use alters the ways people interpret their environment and navigate through it. We argue that GPS-based car navigation might disengage peo- ple from their surrounding environment, but also has the potential to open up novel ways to engage with it. We pre- sent an ethnographically-informed study
GPS World | November2011 www.gpsworld.com44 INNOVATION | System Design & Test
Stanford University
GPS World | November2011 www.gpsworld.com44 INNOVATION | System Design & Test T he Navstar Global Positioning System is so far the most widely used space-based positioning, navigation, and timing system. GPS to at least four GPS sat- ellites in view, as well as the position and clock data for these satellites
Nation-wide RTK-GPS based on FKP method and applications for human navigation and location based services
Sumio Usui; Hiroshi Higuchi; Junshiro Kanda; Koji Wakimoto; Satoshi Tanaka; Fumiaki Satoh
High accuracy positioning services named PAS, based on nation wide RTK-GPS and FKP method, has been realized in Japan, and commercially operated since September 2003. Cm-level accuracy is obtained and uniformity in the service area is also validated. Application to human navigation prototype system is also shown with real image on cellular phone, and will be linked to PAS system
A derivative UKF for tightly coupled INS/GPS integrated navigation.
Hu, Gaoge; Gao, Shesheng; Zhong, Yongmin
The tightly coupled INS/GPS integration introduces nonlinearity to the measurement equation of the Kalman filter due to the use of raw GPS pseudorange measurements. The extended Kalman filter (EKF) is a typical method to address the nonlinearity by linearizing the pseudorange measurements. However, the linearization may cause large modeling error or even degraded navigation solution. To solve this problem, this paper constructs a nonlinear measurement equation by including the second-order term in the Taylor series of the pseudorange measurements. Nevertheless, when using the unscented Kalman filter (UKF) to the INS/GPS integration for navigation estimation, it causes a great amount of redundant computation in the prediction process due to the linear feature of system state equation, especially for the case with system state vector in much higher dimension than measurement vector. To overcome this drawback in computational burden, this paper further develops a derivative UKF based on the constructed nonlinear measurement equation. The derivative UKF adopts the concise form of the original Kalman filter (KF) to the prediction process and employs the unscented transformation technique to the update process. Theoretical analysis and simulation results demonstrate that the derivative UKF can achieve higher accuracy with a much smaller computational cost in comparison with the traditional UKF. PMID:25467307
Onboard Navigation Systems Characteristics
NASA Technical Reports Server (NTRS)
The space shuttle onboard navigation systems characteristics are described. A standard source of equations and numerical data for use in error analyses and mission simulations related to space shuttle development is reported. The sensor characteristics described are used for shuttle onboard navigation performance assessment. The use of complete models in the studies depend on the analyses to be performed, the capabilities of the computer programs, and the availability of computer resources.
An Effective Approach to Improving Low-Cost GPS Positioning Accuracy in Real-Time Navigation
Islam, Md. Rashedul; Kim, Jong-Myon
Positioning accuracy is a challenging issue for location-based applications using a low-cost global positioning system (GPS). This paper presents an effective approach to improving the positioning accuracy of a low-cost GPS receiver for real-time navigation. The proposed method precisely estimates position by combining vehicle movement direction, velocity averaging, and distance between waypoints using coordinate data (latitude, longitude, time, and velocity) of the GPS receiver. The previously estimated precious reference point, coordinate translation, and invalid data check also improve accuracy. In order to evaluate the performance of the proposed method, we conducted an experiment using a GARMIN GPS 19xHVS receiver attached to a car and used Google Maps to plot the processed data. The proposed method achieved improvement of 4�10 meters in several experiments. In addition, we compared the proposed approach with two other state-of-the-art methods: recursive averaging and ARMA interpolation. The experimental results show that the proposed approach outperforms other state-of-the-art methods in terms of positioning accuracy. PMID:25136679
Achieving Integrity in an INS\\/GPS Navigation Loop for Autonomous Land Vehicle Applications
Salah Sukkarieh; Eduardo Mario Nebot; Hugh F. Durrant-whyte
The objective of this paper is to introduce and investigate the issue of integrity in an INS\\/GPS navigation loop for autonomous land vehicle applications. The paper briefly outlines the standard fusion algorithm for the INS\\/GPS loop, while the focus is on the detection of possible faults both before and during the fusion process. The concept of fault detection focuses on
High accuracy integrated global positioning system/inertial navigation system LDRD: Final report
Owen, T.E.; Meindl, M.A.; Fellerhoff, J.R.
This report contains the results of a Sandia National Laboratories Directed Research and Development (LDRD) program to investigate the integration of Global Positioning System (GPS) and inertial navigation system (INS) technologies toward the goal of optimizing the navigational accuracy of the combined GPSANS system. The approach undertaken is to integrate the data from an INS, which has long term drifts, but excellent short term accuracy, with GPS carrier phase signal information, which is accurate to the sub-centimeter level, but requires continuous tracking of the GPS signals. The goal is to maintain a sub-meter accurate navigation solution while the vehicle is in motion by using the GPS measurements to estimate the INS navigation errors and then using the refined INS data to aid the GPS carrier phase cycle slip detection and correction and bridge dropouts in the GPS data. The work was expanded to look at GPS-based attitude determination, using multiple GPS receivers and antennas on a single platform, as a possible navigation aid. Efforts included not only the development of data processing algorithms and software, but also the collection and analysis of GPS and INS flight data aboard a Twin Otter aircraft. Finally, the application of improved navigation system accuracy to synthetic aperture radar (SAR) target location is examined.
Development of a tightly integrated ring laser gyro based navigation system
C. Kerwin; R. Cnossen; C. Kiel; M. Lynch
The development of a small, tightly integrated GPS\\/inertial navigation system (INS) is being pursued following the development of a miniaturized GPS receiver and a compact multiaxis ring laser gyro. The tradeoffs involved in achieving the present system architecture, along with a system description and performance summary, are presented. A description of both the inertial hardware and the GPS receiver hardware,
GPS inferred geocentric reference frame for satellite positioning and navigation
NASA Technical Reports Server (NTRS)
Malla, Rajendra P.; Wu, Sien-Chong
Accurate geocentric three-dimensional positioning is of great importance for various geodetic and oceanographic applications. While relative positioning accuracy of a few centimeters has become a reality using Very Long Baseline Interferometry (VLBI), the uncertainty in the offset of the adopted coordinate system origin from the geocenter is still believed to be of the order of one meter. Satellite Laser Ranging (SLR) is capable of determining this offset to better than 10 cm, though, because of the limited number of satellites, this requires a long arc of data. The Global Positioning System (GPS) measurements provide a powerful alternative for an accurate determination of this origin offset in relatively short period of time. Two strategies are discussed, the first utilizes the precise relative positions predetermined by VLBI, whereas the second establishes a reference frame by holding only one of the tracking sites longitude fixed. Covariance analysis studies indicate that geocentric positioning to an accuracy of a few centimeters can be achieved with just one day of precise GPS pseudorange and carrier phase data.
Cloud Absorption Radiometer Autonomous Navigation System - CANS
NASA Technical Reports Server (NTRS)
Kahle, Duncan; Gatebe, Charles; McCune, Bill; Hellwig, Dustan
CAR (cloud absorption radiometer) acquires spatial reference data from host aircraft navigation systems. This poses various problems during CAR data reduction, including navigation data format, accuracy of position data, accuracy of airframe inertial data, and navigation data rate. Incorporating its own navigation system, which included GPS (Global Positioning System), roll axis inertia and rates, and three axis acceleration, CANS expedites data reduction and increases the accuracy of the CAR end data product. CANS provides a self-contained navigation system for the CAR, using inertial reference and GPS positional information. The intent of the software application was to correct the sensor with respect to aircraft roll in real time based upon inputs from a precision navigation sensor. In addition, the navigation information (including GPS position), attitude data, and sensor position details are all streamed to a remote system for recording and later analysis. CANS comprises a commercially available inertial navigation system with integral GPS capability (Attitude Heading Reference System AHRS) integrated into the CAR support structure and data system. The unit is attached to the bottom of the tripod support structure. The related GPS antenna is located on the P-3 radome immediately above the CAR. The AHRS unit provides a RS-232 data stream containing global position and inertial attitude and velocity data to the CAR, which is recorded concurrently with the CAR data. This independence from aircraft navigation input provides for position and inertial state data that accounts for very small changes in aircraft attitude and position, sensed at the CAR location as opposed to aircraft state sensors typically installed close to the aircraft center of gravity. More accurate positional data enables quicker CAR data reduction with better resolution. The CANS software operates in two modes: initialization/calibration and operational. In the initialization/calibration mode, the software aligns the precision navigation sensors and initializes the communications interfaces with the sensor and the remote computing system. It also monitors the navigation data state for quality and ensures that the system maintains the required fidelity for attitude and positional information. In the operational mode, the software runs at 12.5 Hz and gathers the required navigation/attitude data, computes the required sensor correction values, and then commands the sensor to the required roll correction. In this manner, the sensor will stay very near to vertical at all times, greatly improving the resulting collected data and imagery. CANS greatly improves quality of resulting imagery and data collected. In addition, the software component of the system outputs a concisely formatted, high-speed data stream that can be used for further science data processing. This precision, time-stamped data also can benefit other instruments on the same aircraft platform by providing extra information from the mission flight.
Accuracy analysis of strapdown inertial navigation systems
NASA Astrophysics Data System (ADS)
Kortunov, V.; Dybska, I.; Proskura, G.; Trachsel, T.
This paper discusses correction methods of INS/GPS systems. Different schemes are considered: open loop correction scheme, scheme with estimated instrumental errors feedback, scheme with state space feedback and scheme with navigation parameter errors feedback INS correction is considered as the process of control on the base of combined method. Nonlinear equations of INS angular errors in quaternion form are obtained. Nonliear and linear equations of navigation and orientation parameters errors are presented. Observability and detectability of linear equations of INS errors at different component combination of error vector are evaluated. Precision analysis of instrumental errors compensation is carried out. The results of testing INS/GPS systems on laboratory bench and car are presented.
A Multi-Constellations Satellite Selection Algorithm for Integrated Global Navigation Satellite Systems
Duangduen Roongpiboonsopit; Hassan A. Karimi
The U.S. Global Positioning System (GPS) is currently the only fully operational global navigation satellite system (GNSS) that has been widely utilized in navigation and data collection, among other applications. In the near future, there will be other GNSSs such as the Russian GLONASS, the European Galileo, and the Chinese Compass that provide compatible services with GPS and will be
Extended Kalman filter synthesis for integrated global positioning\\/inertial navigation systems
Farhan A. Faruqi; Kenneth J. Turner
The integrated global position system (GPS)\\/inertial navigation system (INS) is a cost-effective way of providing an accurate and reliable navigation system for civil and military aviation. These systems also provide low cost solutions to mid-course navigation and guidance of medium- and long-range weapon systems. In this paper, an error model developed earlier is used for GPS\\/INS filter mechanization (F.A. Faruqi,
A New Indoor Positioning System Architecture Using GPS Signals.
Xu, Rui; Chen, Wu; Xu, Ying; Ji, Shengyue
The pseudolite system is a good alternative for indoor positioning systems due to its large coverage area and accurate positioning solution. However, for common Global Positioning System (GPS) receivers, the pseudolite system requires some modifications of the user terminals. To solve the problem, this paper proposes a new pseudolite-based indoor positioning system architecture. The main idea is to receive real-world GPS signals, repeat each satellite signal and transmit those using indoor transmitting antennas. The transmitted GPS-like signal can be processed (signal acquisition and tracking, navigation data decoding) by the general receiver and thus no hardware-level modification on the receiver is required. In addition, all Tx can be synchronized with each other since one single clock is used in Rx/Tx. The proposed system is simulated using a software GPS receiver. The simulation results show the indoor positioning system is able to provide high accurate horizontal positioning in both static and dynamic situations. PMID:25938199
A New Indoor Positioning System Architecture Using GPS Signals
Xu, Rui; Chen, Wu; Xu, Ying; Ji, Shengyue
The pseudolite system is a good alternative for indoor positioning systems due to its large coverage area and accurate positioning solution. However, for common Global Positioning System (GPS) receivers, the pseudolite system requires some modifications of the user terminals. To solve the problem, this paper proposes a new pseudolite-based indoor positioning system architecture. The main idea is to receive real-world GPS signals, repeat each satellite signal and transmit those using indoor transmitting antennas. The transmitted GPS-like signal can be processed (signal acquisition and tracking, navigation data decoding) by the general receiver and thus no hardware-level modification on the receiver is required. In addition, all Tx can be synchronized with each other since one single clock is used in Rx/Tx. The proposed system is simulated using a software GPS receiver. The simulation results show the indoor positioning system is able to provide high accurate horizontal positioning in both static and dynamic situations. PMID:25938199
GPS error modeling and OTF ambiguity resolution for high-accuracy GPS\\/INS integrated system
D. A. Grejner-Brzezinska; R. da; C. Toth
.�� The Center for Mapping at The Ohio State University is currently developing a fully digital Airborne Integrated Mapping System\\u000a (AIMS) for large-scale mapping and other precise positioning applications. AIMS, installed in an aerial platform, incorporates\\u000a state-of-the-art positioning [differential Global Positioning System (GPS) integrated with an Inertial Navigation System (INS)]\\u000a and imaging (Charge-Coupled Device) technologies. The project goal is to
Ranging error overbounds for navigation integrity of local area augmented GPS
NASA Astrophysics Data System (ADS)
Sayim, Irfan
The use of Differential GPS (DGPS) in aviation has been especially attractive in the past decade because of its potential to provide the means for satellite-based aircraft navigation spanning all aspects of flight, from takeoff to touchdown, with low cost and high availability. While this has been an inspiring goal, serious technical obstacles exist, the most difficult of which are related with navigation integrity for aircraft precision approach and landing. For example, for Category I precision approach, it is required that integrity risk (probability of hazardously misleading navigation information) never exceed 10-8. The Local Area Augmentation System (LAAS) is the DGPS architecture standard under development by the Federal Aviation Administration (FAA) to provide precision approach and landing navigation for civil aircraft. Navigation integrity risk for LAAS will be managed at the aircraft via the computation of Protection Levels, which are position error bounds within which navigation integrity is to be ensured. Existing standardized algorithms for the generation of the protection levels implicitly assume zero-mean, normally distributed ranging error distributions. Unfortunately, while the assumed error model is likely consistent with the effects of certain error sources (receiver thermal noise and diffuse multipath), it is widely understood that significant remaining errors, such as ground reflection multipath and systematic receiver/antenna errors, cannot be directly modeled by zero-mean normal distributions. In this dissertation, the critical issues concerning establishment and sufficiency of overbounding ranging error distributions are addressed in detail. These include: quantification of the sensitivity of integrity risk due to statistical uncertainty; derivation of theoretical bounding models for non-zero-mean error sources; derivation of new bounding distribution models for non-gaussian ground-reflection multipath error; quantification and compensation for the effects of seasonal variation of multipath error; development, implementation, and testing of a new, adaptive binning algorithm to conservatively accommodate non-stationary and time-correlated empirical satellite ranging error data.
Topex orbit determination using GPS tracking system
Hyung Jin Rim
An extensive simulation study was performed to analyze several aspects of Topex Precise Orbit Determination (POD) using the Global Positioning System (GPS). Since the error modeling is the key to such an experiment, extensive investigation was performed based on real GPS data processing experience to create realistic measurement and dynamic error models for GPS. Double-differenced Topex-GPS phase measurements were evaluated
Pulsar Navigation in the Solar System
Dong, Jiang
The X-ray Pulsar-based Autonomous Navigation(XNAV) were recently tested which use the Crab pulsar (PSR B0531+21) in the USA Experiment on flown by the Navy on the Air Force Advanced Research and Global Observation Satellite (ARGOS) under the Space Test Program. It provide the way that the spacecraft could autonomously determine its position with respect to an inertial origin. Now I analysis the sensitivity of the exist instrument and the signal process to use radio pulsar navigation and discuss the integrated navigation use pulsar,then give the different navigation mission analysis and design process basically which include the space, the airborne, the ship and the land of the planet or the lunar.So the pulsar navigation can give the continuous position in deep spaces, that means we can freedom fly successfully in the solar system use celestial navigation that include pulsar and traditional star sensor.It also can less or abolish the depend of Global Navigation Satellite System which include GPS, GRONSS, Gali...
Satellite Navigation Systems: Policy, Commercial and Technical Interaction
M. Rycroft
This book adopts a broad perspective on positioning and navigation systems which rely on Earth orbiting satellites for their successful operation. The first of such global systems was the US Global Positioning System (GPS), and the next the Russian GLONASS system. Now studies relating to Europe's future Galileo system are gaining momentum and other nations are planning regional augmentation systems.
Navigating the Return Trip from the Moon Using Earth-Based Ground Tracking and GPS
NASA Technical Reports Server (NTRS)
Berry, Kevin; Carpenter, Russell; Moreau, Michael C.; Lee, Taesul; Holt, Gregg N.
NASA s Constellation Program is planning a human return to the Moon late in the next decade. From a navigation perspective, one of the most critical phases of a lunar mission is the series of burns performed to leave lunar orbit, insert onto a trans-Earth trajectory, and target a precise re-entry corridor in the Earth s atmosphere. A study was conducted to examine sensitivity of the navigation performance during this phase of the mission to the type and availability of tracking data from Earth-based ground stations, and the sensitivity to key error sources. This study also investigated whether GPS measurements could be used to augment Earth-based tracking data, and how far from the Earth GPS measurements would be useful. The ability to track and utilize weak GPS signals transmitted across the limb of the Earth is highly dependent on the configuration and sensitivity of the GPS receiver being used. For this study three GPS configurations were considered: a "standard" GPS receiver with zero dB antenna gain, a "weak signal" GPS receiver with zero dB antenna gain, and a "weak signal" GPS receiver with an Earth-pointing direction antenna (providing 10 dB additional gain). The analysis indicates that with proper selection and configuration of the GPS receiver on the Orion spacecraft, GPS can potentially improve navigation performance during the critical final phases of flight prior to Earth atmospheric entry interface, and may reduce reliance on two-way range tracking from Earth-based ground stations.
The Honeywell\\/DND helicopter integrated navigation system (HINS)
G. West-Vukovich; J. Zywiel; B. M. Scherzinger; H. Russell; S. Burke
The development of prototype of a high-performance, fault-tolerant navigation system for Canada's anti-submarine-warfare helicopter is discussed. HINS consists of three primary navigation subsystems (an F 3INS, a five channel P-code GPS (global positioning system), and a Doppler velocity sensor) and three secondary sensors (a strapdown magnetometer, a vertical gyro, and an air data system). The system is designed to blend
U.S. Space Shuttle GPS navigation capability for all mission phases
Peter Kachmar; William Chu; Moises Montez
Incorporating a GPS capability on the Space Shuttle presented unique system integration design considerations and has led to an integration concept that has minimum impact on the existing Shuttle hardware and software systems. This paper presents the Space Shuttle GPS integrated design and the concepts used in implementing this GPS capability. The major focus of the paper is on the
Integrated GPS-aided Inertial Lidar and Optical Imaging Systems for Aerial Mapping
R. D. Sanchez; J. Mullins
High-resolution airborne Lidar and optical imaging systems with onboard data collection based on the Global Positioning System (GPS) and inertial navigation syste ms (INS) technology may offer the means to gather accurate topographic map information. As a follow-up to earlier investigations, in May 2005 an airborne integrated GPS -aided inertial Lidar and optical imaging system was used to collect data
An embedded high sensitivity navigation receiver for GPS
Yangchun Shi; Lingwen Zhang; YouBao Liu
A high sensitivity navigation receiver based on FPGA and DSP was presented in this paper, which performed to mitigate cross correlations between multiple satellite signals. The hardware was consisted of RF parts, FPGA and DSP. The core chips were SPARTAN3 and TMS320VC5402, which were adapted to process navigation data and calculate user position. The RF Front-End received the navigation signal
Navigator GPS Receiver for Fast Acquisition and Weak Signal Space Applications
NASA Technical Reports Server (NTRS)
Winternitz, Luke; Moreau, Michael; Boegner, Gregory J.; Sirotzky, Steve
NASA Goddard Space Flight Center (GSFC) is developing a new space-borne GPS receiver that can operate effectively in the full range of Earth orbiting missions from Low Earth Orbit (LEO) to geostationary and beyond. Navigator is designed to be a fully space flight qualified GPS receiver optimized for fast signal acquisition and weak signal tracking. The fast acquisition capabilities provide exceptional time to first fix performance (TIFF) with no a priori receiver state or GPS almanac information, even in the presence of high Doppler shifts present in LEO (or near perigee in highly eccentric orbits). The fast acquisition capability also makes it feasible to implement extended correlation intervals and therefore significantly reduce Navigator s acquisition threshold. This greatly improves GPS observability when the receiver is above the GPS constellation (and satellites must be tracked from the opposite side of the Earth) by providing at least 10 dB of increased acquisition sensitivity. Fast acquisition and weak signal tracking algorithms have been implemented and validated on a hardware development board. A fully functional version of the receiver, employing most of the flight parts, with integrated navigation software is expected by mid 2005. An ultimate goal of this project is to license the Navigator design to an industry partner who will then market the receiver as a commercial product.
Development of an Autonomous Mobile Surveillance System Using a Network-based RTK-GPS
Jun-ichi Meguro; Takumi Hashizume; Jun-ichi Takiguchi; Ryujirou Kurosaki
This paper describes an autonomous mobile surveillance system usually used in a factory premises with some high-rise buildings. This system consists of a wireless LAN network, a base station and an autonomous vehicle. The vehicle is equipped with a GPS\\/INS navigation system using the network-based Real-Time Kinematic GPS (RTK-GPS) with Positioning Augmentation Services (PASTM, Mitsubishi Electric Corporation 2003), an Area
Geostar - Navigation location system
NASA Astrophysics Data System (ADS)
Keyser, Donald A.
The author describes the Radiodetermination Satellite Service (RDSS). The initial phase of the RDSS provides for a unique service enabling central offices and headquarters to obtain position-location information and receive short digital messages from mobile user terminals throughout the contiguous United States, southern Canada, and northern Mexico. The system employs a spread-spectrum, CDMA modulation technique allowing multiple customers to use the system simultaneously, without preassigned coordination with fellow users. Position location is currently determined by employing an existing radio determination receiver, such as Loran-C, GPS, or Transit, in the mobile user terminal. In the early 1990s position location will be determined at a central earth station by time-differential ranging of the user terminals via two or more geostationary satellites. A brief overview of the RDSS system architecture is presented with emphasis on the user terminal and its diverse applications.
Development of high precision and multifunctional timing system using integrated GPS\\/BD receiver
Li Gun; Wu Fu-ping; Wei Jing-fa; Huang Xian-he
A highly precise and multifunctional timing system using the self development integrated GPS\\/BD time receiver is presented in this paper. The authors firstly designed an integrated GPS\\/BD (compass or Beidou navigation system of China) time receiver for time and frequency synchronization in a local network, and describing the main issues and the solution of the receiver implement in detail, and
Civil satellite navigation systems
NASA Astrophysics Data System (ADS)
Blanchard, Walter F.
The use of satellite navigation for civil purposes is examined critically to compare the merits and costs of existing and practical satellite systems. Accuracy and range considerations are reviewed, and the basic requirements of radionavigation systems are set forth. Specific data are given regarding coverage area, integration with ground-based systems, monitoring and control, and accuracy. Systems reviewed include 'Starfix,' Inmarsat, EVA Vavsat, and Geostar/Locstar/Omnitracs, and extensive illustrations are provided to demonstrate constellation geometries. When in view, two or three geosynchronous satellites can provide acceptable fixing, and 9 satellites can provide global coverage. It is argued that systems such as 'Starfix' are commercially viable with less than 100 users, and Inmarsat is identified as an effective European civil system.
Navigating low altitude satellites using the current four Navstar\\/GPS satellites
S. Jorgensen
It is shown that Landsat 4 can be quite accurately navigated over CONUS throughout most of the year using only the four fully operational GPS satellites. It is noted that the Landsat 4 mission covers only a very small fraction of the earth's surface. Typically, only two out of the roughly fourteen and one-half orbits per day are used and
Vision enhanced navigation for unmanned systems
NASA Astrophysics Data System (ADS)
Wampler, Brandon Loy
A vision based simultaneous localization and mapping (SLAM) algorithm is evaluated for use on unmanned systems. SLAM is a technique used by a vehicle to build a map of an environment while concurrently keeping track of its location within the map, without a priori knowledge. The work in this thesis is focused on using SLAM as a navigation solution when global positioning system (GPS) service is degraded or temporarily unavailable. Previous work on unmanned systems that lead up to the determination that a better navigation solution than GPS alone is first presented. This previous work includes control of unmanned systems, simulation, and unmanned vehicle hardware testing. The proposed SLAM algorithm follows the work originally developed by Davidson et al. in which they dub their algorithm MonoSLAM [1--4]. A new approach using the Pyramidal Lucas-Kanade feature tracking algorithm from Intel's OpenCV (open computer vision) library is presented as a means of keeping correct landmark correspondences as the vehicle moves through the scene. Though this landmark tracking method is unusable for long term SLAM due to its inability to recognize revisited landmarks, as opposed to the Scale Invariant Feature Transform (SIFT) and Speeded Up Robust Features (SURF), its computational efficiency makes it a good candidate for short term navigation between GPS position updates. Additional sensor information is then considered by fusing INS and GPS information into the SLAM filter. The SLAM system, in its vision only and vision/IMU form, is tested on a table top, in an open room, and finally in an outdoor environment. For the outdoor environment, a form of the slam algorithm that fuses vision, IMU, and GPS information is tested. The proposed SLAM algorithm, and its several forms, are implemented in C++ using an Extended Kalman Filter (EKF). Experiments utilizing a live video feed from a webcam are performed. The different forms of the filter are compared and conclusions are made on the effectiveness of the SLAM algorithm for use on the current unmanned vehicles in Purdue's Hybrid Systems Lab. Recommendations for future improvements in applying computer vision to unmanned systems are also presented in the final chapter.
Spatial Mental Representation: Implications for Navigation System Design
Patel, Aniruddh D.
, on the ground, or surgically within the body. As such, design principles for presenting spatial information-vehicle, aviation, and endoscopic navigation systems. Taken together, the research suggests three general principles.), detailed verbal spatial descriptions, global positioning systems (GPS), or even virtual reality
14 CFR Special Federal Aviation... - Special Operating Rules for the Conduct of Instrument Flight Rules (IFR) Area Navigation (RNAV...
Code of Federal Regulations, 2013 CFR
...Components of the GNSS include GPS, the Global Orbiting Navigation Satellite System, and WAAS satellites. Global Positioning System (GPS). GPS is a satellite-based radio navigational, positioning, and time transfer system....
14 CFR Special Federal Aviation... - Special Operating Rules for the Conduct of Instrument Flight Rules (IFR) Area Navigation (RNAV...
Code of Federal Regulations, 2012 CFR
...Components of the GNSS include GPS, the Global Orbiting Navigation Satellite System, and WAAS satellites. Global Positioning System (GPS). GPS is a satellite-based radio navigational, positioning, and time transfer system....
14 CFR Special Federal Aviation... - Special Operating Rules for the Conduct of Instrument Flight Rules (IFR) Area Navigation (RNAV...
Code of Federal Regulations, 2011 CFR
...Components of the GNSS include GPS, the Global Orbiting Navigation Satellite System, and WAAS satellites. Global Positioning System (GPS). GPS is a satellite-based radio navigational, positioning, and time transfer system....
14 CFR Special Federal Aviation... - Special Operating Rules for the Conduct of Instrument Flight Rules (IFR) Area Navigation (RNAV...
Code of Federal Regulations, 2010 CFR
...Components of the GNSS include GPS, the Global Orbiting Navigation Satellite System, and WAAS satellites. Global Positioning System (GPS). GPS is a satellite-based radio navigational, positioning, and time transfer system....
14 CFR Special Federal Aviation... - Special Operating Rules for the Conduct of Instrument Flight Rules (IFR) Area Navigation (RNAV...
Code of Federal Regulations, 2014 CFR
...Components of the GNSS include GPS, the Global Orbiting Navigation Satellite System, and WAAS satellites. Global Positioning System (GPS). GPS is a satellite-based radio navigational, positioning, and time transfer system....
Virtual instrumentation-based system in a real-time applications of GPS\\/GIS
Chih-Yeh King
Global Positioning System (GPS) is a satellite-based radio positioning and navigation system providing accurate, common 3-D grid position, velocity and time information to users anywhere on or near the earth. It consists of a constellation of 24 satellites with atomic clocks, along with the global satellite tacking network and the sophisticated ground processing stations, that together provide precise navigation coordinates
Submeter navigation grid system concept
John Dowdle; Karl Flueckiger
This paper describes a concept for a system that provides the capability for accurate targeting and weapon delivery within a prescribed geographic context. This system, entitled submeter navigation grid, defines a geographic region that enables targeting platforms to perform relative navigation to the centimetre level. Ultimately, targeting information is delivered to an appropriate tactical platform, and the system enables precision
Passive GPS-Free Navigation for Small UAVs Jack Langelaan
Langelaan, Jack W.
unit and a monocular camera) is presented. The navigation task is cast as a Simul- taneous Localization and Mapping (SLAM) problem. While SLAM has been the subject of a great deal of research, the highly non or are obscured by natural or man-made features. Small UAVs, however, present a unique set of challenges ul
An alternative ionospheric correction model for global navigation satellite systems
NASA Astrophysics Data System (ADS)
Hoque, M. M.; Jakowski, N.
The ionosphere is recognized as a major error source for single-frequency operations of global navigation satellite systems (GNSS). To enhance single-frequency operations the global positioning system (GPS) uses an ionospheric correction algorithm (ICA) driven by 8 coefficients broadcasted in the navigation message every 24 h. Similarly, the global navigation satellite system Galileo uses the electron density NeQuick model for ionospheric correction. The Galileo satellite vehicles (SVs) transmit 3 ionospheric correction coefficients as driver parameters of the NeQuick model. In the present work, we propose an alternative ionospheric correction algorithm called Neustrelitz TEC broadcast model NTCM-BC that is also applicable for global satellite navigation systems. Like the GPS ICA or Galileo NeQuick, the NTCM-BC can be optimized on a daily basis by utilizing GNSS data obtained at the previous day at monitor stations. To drive the NTCM-BC, 9 ionospheric correction coefficients need to be uploaded to the SVs for broadcasting in the navigation message. Our investigation using GPS data of about 200 worldwide ground stations shows that the 24-h-ahead prediction performance of the NTCM-BC is better than the GPS ICA and comparable to the Galileo NeQuick model. We have found that the 95 percentiles of the prediction error are about 16.1, 16.1 and 13.4 TECU for the GPS ICA, Galileo NeQuick and NTCM-BC, respectively, during a selected quiet ionospheric period, whereas the corresponding numbers are found about 40.5, 28.2 and 26.5 TECU during a selected geomagnetic perturbed period. However, in terms of complexity the NTCM-BC is easier to handle than the Galileo NeQuick and in this respect comparable to the GPS ICA.
Delay/Doppler-Mapping GPS-Reflection Remote-Sensing System
NASA Technical Reports Server (NTRS)
Lowe, Stephen; Kroger, Peter; Franklin, Garth; LeBrecque, John; Lerma, Jesse; Lough, Michael; Marcin, Martin; Muellerschoen, Ronald; Spitzmesser, Donovan; Young, Lawrence
A radio receiver system that features enhanced capabilities for remote sensing by use of reflected Global Positioning System (GPS) signals has been developed. This system was designed primarily for ocean altimetry, but can also be used for scatterometry and bistatic synthetic-aperture radar imaging. Moreover, it could readily be adapted to utilize navigation-satellite systems other than the GPS, including the Russian Global Navigation Satellite System GLONASS) and the proposed European Galileo system. This remote-sensing system offers both advantages and disadvantages over traditional radar altimeters: One advantage of GPS-reflection systems is that they cost less because there is no need to transmit signals. Another advantage is that there are more simultaneous measurement opportunities - one for each GPS satellite in view. The primary disadvantage is that in comparison with radar signals, GPS signals are weaker, necessitating larger antennas and/or longer observations. This GPS-reflection remote-sensing system was tested in aircraft and made to record and process both (1) signals coming directly from GPS satellites by means of an upward-looking antenna and (2) GPS signals reflected from the ground by means of a downward-looking antenna. In addition to performing conventional GPS processing, the system records raw signals for postprocessing as required.
Tightly Coupled Visual-Inertial Navigation System Using Optical Flow
Daraio, Chiara
vehicles (UAV), in GPS-denied environ- ments using vision sensors (? ),(2). Especially optical flow- basedTightly Coupled Visual-Inertial Navigation System Using Optical Flow Simon Lynen Sammy Omari relies on optical flow- as well as gyroscope and accelerometer measurements. The underlying assumption
The purpose of this SOP is to describe the general procedures for the operation and initialization of the Magellan Global Positioning System (GPS) Satellite Navigator. This procedure was followed to ensure consistent data retrieval during the Arizona NHEXAS project and the "Bord...
Wellborne inertial navigation system
Kelsey, J.R.
A phototype wireline tool which includes a downhole inertial platform and a surface computer to spatially map a well is described. The hardware consists of a single-gimbaled inertial platform with accelerometers and gyros to obtain three-axis motion information. The gyroscope and accelerometer outputs are transmitted to a computer at the surface which calculates probe attitude relative to north, east, and vertical. Double integration of the accelerometer data provides the position information. A conventional 7-conductor wireline is used for the system data transmission. System accuracy is enhanced by advances made in the computer software which processes the data received from the tool. The software uses statistical sampling estimation to obtain optimal estimates of the system errors. Measurement errors are determined by periodically stopping the tool during the logging procedure and observing the indicated velocity measurements. This procedure, known as Kalman filtering, results in increased accuracy of the data. Present mapping systems have an X-Y-Z location accuracy of +- 100 to +- 200 feet for a typical well depth of 10,000 feet. Test results show that the new system is accurate to about +- 1 foot per 1000 feet of well depth. Unlike conventional systems, the inertial navigator does not require any sort of projection of the cable length (which may not be accurately known). Also this system provides continuous data throughout the wellbore and logging speeds on the order of 10 ft/sec appear possible. The hardware and software associated with this mapping system are described and the recent field test results are reported.
Miniature Space GPS Receiver by Means of Automobile-Navigation Technology
NASA Astrophysics Data System (ADS)
Saito, Hirobumi; Mizuno, Takahide; Kawahara, Kousuke; Saiki, Takanao; Tuda, Yuichi; Fukushima, Yousuke; Hamada, Yusuke; Sasaki, Hiroyuki; Katumoto, Sachiko; Kuroki, Seiji; Kajikawa, Yasuhiro
Miniature space GPS receivers have been developed by means of automobile-navigation technology. We expanded the frequency sweep range in order to cover large Doppler shift on orbit. We tested the performance in low earth orbits by means of a GPS simulator. The range error caused by the receiver is measured to be 0.9m in RMS. The receiver is tolerant for 20krad radiation. Receiver was on-boarded on INDEX (�REIMEI�) satellite, which was launched in 2005. Cold start positioning is confirmed repeatedly to finish within 30min on orbit. The short term random error of GPS positioning is as large as 1.5m for PDDP = 2.7 on orbit. The range error due to the receiver is 0.5m RMS from the flight data. These results on orbit are consistent with the simulation results by means of a GPS simulator. This miniature space GPS receiver is promising as an inexpensive space GPS receiver in commercial market.
Relative navigation requirements for automatic rendezvous and capture systems
NASA Technical Reports Server (NTRS)
Kachmar, Peter M.; Polutchko, Robert J.; Chu, William; Montez, Moises
This paper will discuss in detail the relative navigation system requirements and sensor trade-offs for Automatic Rendezvous and Capture. Rendezvous navigation filter development will be discussed in the context of navigation performance requirements for a 'Phase One' AR&C system capability. Navigation system architectures and the resulting relative navigation performance for both cooperative and uncooperative target vehicles will be assessed. Relative navigation performance using rendezvous radar, star tracker, radiometric, laser and GPS navigation sensors during appropriate phases of the trajectory will be presented. The effect of relative navigation performance on the Integrated AR&C system performance will be addressed. Linear covariance and deterministic simulation results will be used. Evaluation of relative navigation and IGN&C system performance for several representative relative approach profiles will be presented in order to demonstrate the full range of system capabilities. A summary of the sensor requirements and recommendations for AR&C system capabilities for several programs requiring AR&C will be presented.
Relative navigation requirements for automatic rendezvous and capture systems
NASA Astrophysics Data System (ADS)
Kachmar, Peter M.; Polutchko, Robert J.; Chu, William; Montez, Moises
This paper will discuss in detail the relative navigation system requirements and sensor trade-offs for Automatic Rendezvous and Capture. Rendezvous navigation filter development will be discussed in the context of navigation performance requirements for a 'Phase One' AR&C system capability. Navigation system architectures and the resulting relative navigation performance for both cooperative and uncooperative target vehicles will be assessed. Relative navigation performance using rendezvous radar, star tracker, radiometric, laser and GPS navigation sensors during appropriate phases of the trajectory will be presented. The effect of relative navigation performance on the Integrated AR&C system performance will be addressed. Linear covariance and deterministic simulation results will be used. Evaluation of relative navigation and IGN&C system performance for several representative relative approach profiles will be presented in order to demonstrate the full range of system capabilities. A summary of the sensor requirements and recommendations for AR&C system capabilities for several programs requiring AR&C will be presented.
Relative Navigation for the Hubble Servicing Mission using Reflected GPS Signals
NASA Astrophysics Data System (ADS)
Cohen, Ian Ravi
Autonomous rendezvous and docking is an important research area within the new exploration missions called forth by NASA. Relative navigation requires special sensors and algorithms to provide the necessary information. It may be possible to use reflected GPS signals as a source of ``free'' relative navigation measurements. Thus requiring no additional hardware except added algorithmic complexity. This thesis examines the use of an extended Kalman filter with reflected GPS measurements as a form of bi-static radar. It compares two different types of dynamic models, an absolute orbit model versus Hill's equations. The scenarios were implemented in Matlab using Satellite Toolkit to generate a high fidelity truth model. The thesis also examines visibility of reflected signals in a typical Hubble rendezvous scenario. This is done by approximating the Hubble as a cylinder, and using geometric optics to predict the reflective pattern.
Miniaturized GPS/MEMS IMU integrated board
NASA Technical Reports Server (NTRS)
Lin, Ching-Fang (Inventor)
This invention documents the efforts on the research and development of a miniaturized GPS/MEMS IMU integrated navigation system. A miniaturized GPS/MEMS IMU integrated navigation system is presented; Laser Dynamic Range Imager (LDRI) based alignment algorithm for space applications is discussed. Two navigation cameras are also included to measure the range and range rate which can be integrated into the GPS/MEMS IMU system to enhance the navigation solution.
Non-linear mathematical model for integrated global positioning\\/inertial navigation systems
Farhan A. Faruqi
In recent years there has been a major upsurge of interest in the integrated global positioning system (GPS)\\/inertial navigation system (INS) as a cost-effective way of providing accurate and reliable navigation aid for civil and military vehicles (ships, aircrafts, land vehicles). In this paper an error model is developed which can be used for GPS\\/INS filter mechanization. It is shown
Designing Navigation Support in Hypertext Systems Based on Navigation Patterns
ERIC Educational Resources Information Center
Puntambekar, Sadhana; Stylianou, Agni
In this paper, we present two studies designed to help students navigate effectively and learn from a hypertext system, CoMPASS. Our first study ("N" = 74) involved an analysis of students' navigation patterns to group them into clusters, using a "k"-means clustering technique. Based on this analysis, navigation patterns were grouped into four�
Institute of Navigation GPS-2000, Salt Lake City, UT, September 2000. 1 Field Test Results for a Self-Calibrating
Stanford University
Institute of Navigation GPS-2000, Salt Lake City, UT, September 2000. 1 Field Test Results. Conventional GPS pseudolite arrays require that the devices be pre-calibrated through a survey the array self- survey its own relative locations, creating a Self- Calibrating Pseudolite Array (SCPA
Integrated communications and optical navigation system
NASA Astrophysics Data System (ADS)
Mueller, J.; Pajer, G.; Paluszek, M.
The Integrated Communications and Optical Navigation System (ICONS) is a flexible navigation system for spacecraft that does not require global positioning system (GPS) measurements. The navigation solution is computed using an Unscented Kalman Filter (UKF) that can accept any combination of range, range-rate, planet chord width, landmark, and angle measurements using any celestial object. Both absolute and relative orbit determination is supported. The UKF employs a full nonlinear dynamical model of the orbit including gravity models and disturbance models. The ICONS package also includes attitude determination algorithms using the UKF algorithm with the Inertial Measurement Unit (IMU). The IMU is used as the dynamical base for the attitude determination algorithms. This makes the sensor a more capable plug-in replacement for a star tracker, thus reducing the integration and test cost of adding this sensor to a spacecraft. Recent additions include an integrated optical communications system which adds communications, and integrated range and range rate measurement and timing. The paper includes test results from trajectories based on the NASA New Horizons spacecraft.
Mobile GPS tracking system using Holger Vmel
V�mel, Holger
be recorded from launch site (or DSRC!) to avoid drop outs. � Need cell phone communication #12;Mobile GPS tracking system using STRATO Holger V�mel University of Colorado, CIRES and NOAA/CMDL #12;Mobile GPS tracking system using STRATO Huntsville soundings : November 1, 2002 November 2, 2002
Using APEX to Model Anticipated Human Error: Analysis of a GPS Navigational Aid
NASA Technical Reports Server (NTRS)
VanSelst, Mark; Freed, Michael; Shefto, Michael (Technical Monitor)
The interface development process can be dramatically improved by predicting design facilitated human error at an early stage in the design process. The approach we advocate is to SIMULATE the behavior of a human agent carrying out tasks with a well-specified user interface, ANALYZE the simulation for instances of human error, and then REFINE the interface or protocol to minimize predicted error. This approach, incorporated into the APEX modeling architecture, differs from past approaches to human simulation in Its emphasis on error rather than e.g. learning rate or speed of response. The APEX model consists of two major components: (1) a powerful action selection component capable of simulating behavior in complex, multiple-task environments; and (2) a resource architecture which constrains cognitive, perceptual, and motor capabilities to within empirically demonstrated limits. The model mimics human errors arising from interactions between limited human resources and elements of the computer interface whose design falls to anticipate those limits. We analyze the design of a hand-held Global Positioning System (GPS) device used for radical and navigational decisions in small yacht recalls. The analysis demonstrates how human system modeling can be an effective design aid, helping to accelerate the process of refining a product (or procedure).
Simplified Orbit Determination Algorithm for Low Earth Orbit Satellites Using Spaceborne Gps Navigation Sensor
NASA Astrophysics Data System (ADS)
Tukaram Aghav, Sandip; Achyut Gangal, Shashikala
In this paper, the main work is focused on designing and simplifying the orbit determination algorithm which will be used for Low Earth Orbit (LEO) navigation. The various data processing algorithms, state estimation algorithms and modeling forces were studied in detail, and simplified algorithm is selected to reduce hardware burden and computational cost. This is done by using raw navigation solution provided by GPS Navigation sensor. A fixed step-size Runge-Kutta 4th order numerical integration method is selected for orbit propagation. Both, the least square and Extended Kalman Filter (EKF) orbit estimation algorithms are developed and the results of the same are compared with each other. EKF algorithm converges faster than least square algorithm. EKF algorithm satisfies the criterions of low computation burden which is required for autonomous orbit determination. Simple static force models also feasible to reduce the hardware burden and computational cost.
ASRS Database Report Set Global Positioning System (GPS) Reports
ASRS Database Report Set Global Positioning System (GPS) Reports Report Set Description.........................................A variety of reports referencing use of Global Positioning System (GPS) devices. Update Number
HaptiGo Tactile Navigation System�
Regmi, Sarin
Tactile navigation systems employ the use of ones sense of touch with haptic feedback to communicate directions. This type of navigation presents a potentially faster and more accurate mode of navigation than preexisting visual or auditory forms. We...
Space Shuttle Global Positioning System (GPS) testing at NASA Johnson Space Center
NASA Technical Reports Server (NTRS)
Pawlowski, J. F.; Quinn, M.
The present investigation is concerned with the significance of the use of the Global Positioning System (GPS) for the Space Shuttle. On the basis of a study regarding the use of the GPS on the Space Shuttle, it was decided that such a system would greatly benefit Space Shuttle navigation. Studies with GPS user equipment were, therefore, conducted to obtain data and information which would provide a base for the formulation and the further refinement of NASA requirements with respect to the type of set the Shuttle would need. Attention is given to orbit determination, satellite numbers, background information concerning the GPS, the currently available GPS sets, the conducted studies, Shuttle sonic boom recording sites, tests performed with the aid of the Kuiper airborne observatory, and questions regarding the test applicability to Shuttle GPS.
NASA Technical Reports Server (NTRS)
Webb, Frank H.
Geodetic networks support the TRF requirements of NASA ESE missions. Each of SLR, VLBI, GPS substantially and uniquely contributes to TRF determination. NASA's SLR, VLBI, and GPS groups collaborate toward wide-ranging improvements in the next 5 years. NASA leverages considerable resources through its significant activity in international services. NASA faces certain challenges in continuing and advancing these activities. The Terrestrial Reference Frame (TRF) is an accurate, stable set of positions and velocities. The TRF provides the stable coordinate system that allows us to link measurements over space and time. The geodetic networks provide data for determination of the TRF as well as direct science observations.
Visual odometry and map fusion for GPS navigation assistance
Ignacio Parra; Miguel Angel Sotelo; David F. Llorca; C. Fernandez; A. Llamazares; N. Hernandez; I. Garcia
This paper describes a new approach for improving the estimation of the global position of a vehicle in complex urban environments by means of visual odometry and map fusion. The visual odometry system is based on the compensation of the heterodasticity in the 3D input data using a weighted non- linear least squares based system. RANdom SAmple Consensus (RANSAC) based
Kinematic GPS positioning in a highway environment�
Li, Yingfeng
The global positioning system (GPS) is a satellite based navigation system which can give twenty-four hour three-dimensional worldwide coverage. The Differential GPS uses the NAVSTAR satellites and a beacon at a known site ...
Analysis of Spaceborne GPS Systems
NASA Technical Reports Server (NTRS)
Cosmo, Mario L.; Davis, James L.; Elosegui, Pedro; Hill, Michael; ScireScapuzzo, Francesca
A reasonable amount of literature can be found on the general topic of GPS receiving antennas, but very little has been published on spaceborne GPS receiving antennas. This very new topic seems to be so far more of interest for the industrial world than for the academic community. For satellite applications, microstrip antennas are usually preferred over other types of antennas mainly because of their non-electrical characteristics, such as small size, relatively lightweight, shape, possibility of integration with microwave integrated circuits, and relatively low costs. Careful design of patch antennas could meet all the requirements (electrical and non-electrical) of GPS receiving antenna to be mounted on a tethered satellite.
POS\\/MV - system performance with inertial\\/RTK GPS integration
Steven Woolven; Bruno Scherzinger; Mark Field
Describes the Position and Orientation System for Marine Vessels (POS\\/MV), being used in multibeam and geophysical surveys around the world, and its performance using integrated inertial\\/DGPS and real-time kinematic (RTK) GPS data. POS\\/MV is a 3-axis position and orientation measurement system that implements a tightly coupled Kalman filter based integration of an inertial navigator and various forms of GPS. POS\\/MV's
On-line smoothing for an integrated navigation system with low-cost MEMS inertial sensors.
Chiang, Kai-Wei; Duong, Thanh Trung; Liao, Jhen-Kai; Lai, Ying-Chih; Chang, Chin-Chia; Cai, Jia-Ming; Huang, Shih-Ching
The integration of the Inertial Navigation System (INS) and the Global Positioning System (GPS) is widely applied to seamlessly determine the time-variable position and orientation parameters of a system for navigation and mobile mapping applications. For optimal data fusion, the Kalman filter (KF) is often used for real-time applications. Backward smoothing is considered an optimal post-processing procedure. However, in current INS/GPS integration schemes, the KF and smoothing techniques still have some limitations. This article reviews the principles and analyzes the limitations of these estimators. In addition, an on-line smoothing method that overcomes the limitations of previous algorithms is proposed. For verification, an INS/GPS integrated architecture is implemented using a low-cost micro-electro-mechanical systems inertial measurement unit and a single-frequency GPS receiver. GPS signal outages are included in the testing trajectories to evaluate the effectiveness of the proposed method in comparison to conventional schemes. PMID:23443403
An efficient INS\\/GPS impulse response model for bridging GPS outages
Mohammed El-Diasty; Spiros Pagiatakis
The integration of Inertial Navigation System (INS) and Global Positioning System (GPS) architectures can be achieved through the use of many time-domain filters such as, extended Kalman, unscented Kalman, divided difference, and particle filters. The main objective of these filters is to achieve precise fusion of the data from GPS and INS to provide INS-only navigation solution during GPS outages.
Software for a GPS-Reflection Remote-Sensing System
NASA Technical Reports Server (NTRS)
Lowe, Stephen
A special-purpose software Global Positioning System (GPS) receiver designed for remote sensing with reflected GPS signals is described in Delay/Doppler-Mapping GPS-Reflection Remote-Sensing System (NPO-30385), which appears elsewhere in this issue of NASA Tech Briefs. The input accepted by this program comprises raw (open-loop) digitized GPS signals sampled at a rate of about 20 MHz. The program processes the data samples to perform the following functions: detection of signals; tracking of phases and delays; mapping of delay, Doppler, and delay/Doppler waveforms; dual-frequency processing; coherent integrations as short as 125 s; decoding of navigation messages; and precise time tagging of observable quantities. The software can perform these functions on all detectable satellite signals without dead time. Open-loop data collected over water, land, or ice and processed by this software can be further processed to extract geophysical information. Possible examples include mean sea height, wind speed and direction, and significant wave height (for observations over the ocean); bistatic-radar terrain images and measures of soil moisture and biomass (for observations over land); and estimates of ice age, thickness, and surface density (for observations over ice).
Onboard navigation rendezvous expert system
NASA Technical Reports Server (NTRS)
Kocen, Michelle
The Onboard Navigation rendezvous expert system is designed to aid the ground flight controller in monitoring the shuttle onboard navigation system. The system is designed to keep track of the navigation sensors and relative state vectors. In addition, the system also keeps an event log and fills out forms usually handled by the flight controller. This expert system is one of the few rendezvous specific systems being developed for the Mission Control Center. The expert system has been in development for six years. Through these years the system has seen hardware, software, and personnel changes. Initial development was done by the Information Systems Directorate (ISD) and Mission Operations Directorate (MOD) at Johnson Space Center. As of October 1, 1991 the system has been turned over to MOD. The system is completely developed except for some minor adjustments to the user interface. The rule base is in the verification stage with total certification of the system due to be completed by May 1992. Test cases for verification are obtained by saving data used for flight controller integrated simulations. The actual data comes from both the shuttle mission simulator and the Mission Control Center Computer. So far no actual flight data has been available. This paper covers all aspects of the system from the development history to the current hardware, software, and use of the system.
Onboard navigation rendezvous expert system
NASA Astrophysics Data System (ADS)
Kocen, Michelle
The Onboard Navigation rendezvous expert system is designed to aid the ground flight controller in monitoring the shuttle onboard navigation system. The system is designed to keep track of the navigation sensors and relative state vectors. In addition, the system also keeps an event log and fills out forms usually handled by the flight controller. This expert system is one of the few rendezvous specific systems being developed for the Mission Control Center. The expert system has been in development for six years. Through these years the system has seen hardware, software, and personnel changes. Initial development was done by the Information Systems Directorate (ISD) and Mission Operations Directorate (MOD) at Johnson Space Center. As of October 1, 1991 the system has been turned over to MOD. The system is completely developed except for some minor adjustments to the user interface. The rule base is in the verification stage with total certification of the system due to be completed by May 1992. Test cases for verification are obtained by saving data used for flight controller integrated simulations. The actual data comes from both the shuttle mission simulator and the Mission Control Center Computer. So far no actual flight data has been available. This paper covers all aspects of the system from the development history to the current hardware, software, and use of the system.
Intelligent personal navigator supported by knowledge-based systems for estimating dead reckoning navigation parameters
NASA Astrophysics Data System (ADS)
Moafipoor, Shahram
Personal navigators (PN) have been studied for about a decade in different fields and applications, such as safety and rescue operations, security and emergency services, and police and military applications. The common goal of all these applications is to provide precise and reliable position, velocity, and heading information of each individual in various environments. In the PN system developed in this dissertation, the underlying assumption is that the system does not require pre-existing infrastructure to enable pedestrian navigation. To facilitate this capability, a multisensor system concept, based on the Global Positioning System (GPS), inertial navigation, barometer, magnetometer, and a human pedometry model has been developed. An important aspect of this design is to use the human body as navigation sensor to facilitate Dead Reckoning (DR) navigation in GPS-challenged environments. The system is designed predominantly for outdoor environments, where occasional loss of GPS lock may happen; however, testing and performance demonstration have been extended to indoor environments. DR navigation is based on a relative-measurement approach, with the key idea of integrating the incremental motion information in the form of step direction (SD) and step length (SL) over time. The foundation of the intelligent navigation system concept proposed here rests in exploiting the human locomotion pattern, as well as change of locomotion in varying environments. In this context, the term intelligent navigation represents the transition from the conventional point-to-point DR to dynamic navigation using the knowledge about the mechanism of the moving person. This approach increasingly relies on integrating knowledge-based systems (KBS) and artificial intelligence (AI) methodologies, including artificial neural networks (ANN) and fuzzy logic (FL). In addition, a general framework of the quality control for the real-time validation of the DR processing is proposed, based on a two-stage Kalman Filter approach. The performance comparison of the algorithm based on different field and simulated datasets, with varying levels of sensor errors, showed that 90 per cent success rate was achieved in detection of outliers for SL and 80 per cent for SD. The SL is predicted for both KBS-based ANN and FL approaches with an average accumulated error of 2 per cent, observed for the total distance traveled, which is generally an improvement over most of the existing pedometry systems. The target accuracy of the system is +/-(3-5)m CEP50 (circular error, probable 50%). This dissertation provides a performance analysis in the outdoor and indoor environments for different operators. Another objective of this dissertation is to test the system's navigation limitation in DR mode in terms of time and trajectory length in order to determine the upper limit of indoor operations. It was determined that for more than four indoor loops, where the user walked 261m in about 6.5 minutes, the DR performance met the required accuracy specifications. However, these results are only relevant to the existing data. Future studies should consider more comprehensive performance analysis for longer trajectories in challenging environments and possible extension to image-based navigation to expand the indoor capability of the system.
A hybrid indoor navigation system
Andreas Butz; J�rg Baus; Antonio Kr�ger; Marco Lohse
We describe a hybrid building navigation system consisting of stationary information booths and a mobile communication infrastructure feeding small portable devices. The graphical presentations for both the booths and the mobile devices are generated from a common source and for the common task of way finding, but they use different techniques to convey possibly different subsets of the relevant information.
Road to Seamless Positioning: Hybrid Positioning System Combining GPS
Stanford University
Road to Seamless Positioning: Hybrid Positioning System Combining GPS and Television Signals Ju-Yong Do firstname.lastname@example.com GPS Lab Stanford University April 18, 2007 #12;Ju-Yong Do 2007/4/18 GPS: Time and Position Reference Time & Position (4D) Time (1D) Position (3D) + = (GPS: Global Positioning System) Hybrid
Precision navigation for aerospace applications
Stimac, Andrew K. (Andrew Kenneth), 1977-
Navigation is important in a variety of aerospace applications, and commonly uses a blend of GPS and inertial sensors. In this thesis, a navigation system is designed, developed, and tested. Several alternatives are ...
PLANS '84 - Position Location and Navigation Symposium, San Diego, CA, November 26-29, 1984, Record
NASA Astrophysics Data System (ADS)
Questions regarding the applications and equipment of the Global Positioning System (GPS) are discussed, taking into account the use of differential GPS positioning for geodetic applications, the use of Synchromesh for the practical enhancement of GPS service, the synergism of the Global Positioning System and electronic terrain map systems, position location with the NBS/GPS time transfer system, early applications of civil GPS, service outages in GPS associated with satellite failures, precise positioning using a four-channel C/A code GPS receiver, and differential GPS marine navigation. Other topics explored are related to radio navigation systems, mapping and charting, geodesy, the GPS development, strapdown inertial navigation, federal radionavigation policy, marine navigation, aircraft navigation, and the positioning, stabilization, and pointing of space systems. Attention is given to an evaluation of radionavigation systems, control moment gyros for the Space Shuttle, the impact of GPS on ocean surveying, and Kalman filter designs for integrated marine navigation systems.
A robust adaptively filtering algorithm in GPS\\/DR integrated navigation
He Peng-ju; Gao She-sheng; Jiao Ya-ling; Zheng Peng
For the mathematical model based on GPS\\/DR Vehicle Integrated System is non-linear and it's linear filter arouse much errors by EKF, we introduce adaptively robust filter. The simulative computation of the adaptively robust filtering and adaptively kalman filtering are studied respectively in this system. The results show that robust adaptive filtering can determine the covariance matrix of observation noise adaptively
12.215 Modern Navigation, Fall 2002
Herring, T. (Thomas)
Introduces the concepts and applications of navigation techniques using celestial bodies and satellite positioning systems such as the Global Positioning System (GPS). Topics include astronomical observations, radio ...
A Frequency-Domain INS\\/GPS Dynamic Response Method for Bridging GPS Outages
Mohammed El-Diasty; Spiros Pagiatakis
We develop a new frequency-domain dynamic response method to model integrated Inertial Navigation System (INS) and Global Positioning System (GPS) architectures and provide an accurate impulse-response-based INS-only navigation solution when GPS signals are denied (GPS outages). The input to such a dynamic system is the INS-only solution and the output is the INS\\/GPS integration solution; both are used to derive
77 FR 12106 - 88th Meeting: RTCA Special Committee 159, Global Positioning System (GPS)
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The normal natural troubles of driving with GPS
Barry Brown; Eric Laurier
In-car GPS based satellite navigation systems are now a common part of driving, providing turn-by-turn navigation instructions on smartphones, portable units or in-car dashboard navigation systems. This paper uses interactional analysis of video data from fifteen naturalistically recorded journeys with GPS to understand the navigational practices deployed by drivers and passengers. The paper documents five types of 'trouble' where GPS
Performance assessment of GPS augmentation systems
R. L. Houghton; T. P. Strelich; C. M. Cluff; J. C. Valine
GPS augmentation systems such as the Wide-Area Augmentation System (WAAS) require independent performance evaluation. ISTI has developed the Performance Assessment System (PAS) for the FAA to independently monitor and evaluate the performance of the WAAS. The PAS uses National Satellite Test Bed (NSTB) receiver output, plus other sources of independent data, to calculate WAAS-compliant user position solutions. Accuracy and integrity
Tightly Coupled Inertial Navigation System/Global Positioning System (TCMIG)
NASA Technical Reports Server (NTRS)
Watson, Michael D.; Jackson, Kurt (Technical Monitor)
Many NASA applications planned for execution later this decade are seeking high performance, miniaturized, low power Inertial Management Units (IMU). Much research has gone into Micro-Electro-Mechanical System (MEMS) over the past decade as a solution to these needs. While MEMS devices have proven to provide high accuracy acceleration measurements, they have not yet proven to have the accuracy required by many NASA missions in rotational measurements. Therefore, a new solution has been formulated integrating the best of all IMU technologies to address these mid-term needs in the form of a Tightly Coupled Micro Inertial Navigation System (INS)/Global Positioning System (GPS) (TCMIG). The TCMIG consists of an INS and a GPS tightly coupled by a Kalman filter executing on an embedded Field Programmable Gate Array (FPGA) processor. The INS consists of a highly integrated Interferometric Fiber Optic Gyroscope (IFOG) and a MEMS accelerometer. The IFOG utilizes a tightly wound fiber coil to reduce volume and the high level of integration and advanced optical components to reduce power. The MEMS accelerometer utilizes a newly developed deep etch process to increase the proof mass and yield a highly accurate accelerometer. The GPS receiver consists of a low power miniaturized version of the Blackjack receiver. Such an IMU configuration is ideal to meet the mid-term needs of the NASA Science Enterprises and the new launch vehicles being developed for the Space Launch Initiative (SLI).
Reliable GPS-Based Timing for Power Systems: A Multi-Layered Multi-Receiver Architecture
Gao, Grace Xingxin
by phasor measurement units (PMUs) have the potential to augment power system monitoring, control and current phasors at widely dispersed locations in an electric power grid [1]. Such measurements also have. Heng et al. [13] have shown that 0.34% of the navigation messages collected by the geodetic- grade GPS
On the Navigability of Social Tagging Systems
Denis Helic; Christoph Trattner; Markus Strohmaier; Keith Andrews
It is a widely held belief among designers of social tagging systems that tag clouds represent a useful tool for navigation. This is evident in, for example, the increasing number of tagging systems offering tag clouds for navigational purposes, which hints towards an implicit assumption that tag clouds support efficient navigation. In this paper, we examine and test this assumption
Environmental applications of GPS
Vigil, S.A.; Zueck, D.
The use of the Global Positioning System (GPS) has revolutionized air travel, ocean navigation, land navigation, and the collection of environmental data. Although a basic civilian GPS receiver can be purchased for as little as $100, the receiver is only the tip of a 12 billion dollar iceberg. This paper will discuss the history and basic operation of the Global Positioning System, a satellite-based precision positioning and timing service developed and operated by the Department of Defense. It will also describe the accuracy limitations of the civil GPS service and how accuracy can be enhanced by the use of differential GPS (DGPS), using either the free National Differential GPS system, or commercial differential monitor stations. Finally, the paper will discuss the future accuracy upgrades of civil GPS as a result of recent federal policy decisions.
Autonomous navigation system. [gyroscopic pendulum for air navigation
NASA Technical Reports Server (NTRS)
Merhav, S. J. (inventor)
An inertial navigation system utilizing a servo-controlled two degree of freedom pendulum to obtain specific force components in the locally level coordinate system is described. The pendulum includes a leveling gyroscope and an azimuth gyroscope supported on a two gimbal system. The specific force components in the locally level coordinate system are converted to components in the geographical coordinate system by means of a single Euler transformation. The standard navigation equations are solved to determine longitudinal and lateral velocities. Finally, vehicle position is determined by a further integration.
Application of GPS attitude determination to gravity gradient stabilized spacecraft
E. G. Lightsey; Clark E. Cohen; Bradford W. Parkinson
Recent advances in the Global Positioning System (GPS) technology have initiated a new era in aerospace navigation and control. GPS receivers have become increasingly compact and affordable, and new developments have made attitude determination using subcentimeter positioning among two or more antennas feasible for real-time applications. GPS-based attitude control systems will become highly portable packages which provide time, navigation, and
Testing Rtk GPS System In Urban Areas
A. Pirti; E. Ata
RTK GPS is provided with cm accuracy and real time surveying system. For providing this conditions, the reference is necessary for high accuracy position. Because this sta- tion is transmitted the corrections to the other receivers. At the some time this system is required common satellites on the receiver to compute integer ambiguity solution. In addition to the conditions, the
NSDL National Science Digital Library
This Air and Space Museum website provides detailed information about how GPS (Global Positioning System) works. Beginning with technology that existed before GPS, such as the sextant and the TRANSIT satellite, it provides information about land, air, and sea navigation, Earth mapping, land management, and scientific applications.
Deep space navigation systems and operations
J. F. Jordan
The history of the deep space navigation system developed by NASA is outlined. Its application to Mariner, Viking and Pioneer missions is reviewed. Voyager navigation results for Jupiter and Saturn are commented on and velocity correction in relation to fuel expenditure and computer time are discussed. The navigation requirements of the Gahleo and Venus orbiting imaging radar (VOIR) missions are
GPS Signal-in-Space Integrity Performance Evolution in the
Stanford University
, Fellow, IEEE Stanford University Knowledge of the Global Positioning System (GPS) signal-in-space (SIS Global Positioning System (GPS) is so far the most widely used space-based positioning, navigation
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
Intelligent Library Navigation using Location-aware Systems The Newman Project
McCrickard, Scott
and Principles]: User/Machine Systems � Human Factors; H.3.3 [Information Search and Retrieval]: Information. Examples of these systems range from in-car GPS navigation systems to Meetro's social networking suite [5 of emphasis was placed on understanding the conventional activities performed by users in a library to both
General GPS Antenna Information APPLICATION NOTE
Berns, Hans-Gerd
General GPS Antenna Information APPLICATION NOTE #12;Global Positioning System and Precise Time & Frequency The Global Positioning System (GPS) is a worldwide radio-navigation system formed from a constellation of 24 satellites that continuously orbit the earth. Each GPS satellite has on board several atomic
Calibration of low cost MEMS inertial Measurement Unit for an FPGA-based navigation system
Lei Wang; Yongping Hao; Fei Wang
According to a small, lightweight, low-cost high performance inertial Measurement Units(IMU), an effective calibration method is implemented to evaluate the performance of Micro-Electro-Mechanical Systems(MEMS) sensors suffering from various errors to get acceptable navigation results. A prototype development board based on FPGA, dual core processor's configuration for INS\\/GPS integrated navigation system is designed for experimental testing. The significant error sources of
Thermal Calibration of MEMS Inertial Sensors for an FPGA-Based Navigation System
Lei Wang; Yongping Hao; Zesong Wei; Fei Wang
Based on a small, lightweight, low-cost high performance inertial Measurement Units (IMU), an effective calibration method is implemented to evaluate the performance of Micro-Electro-Mechanical Systems (MEMS) sensors suffering from various errors to get acceptable navigation results. A prototype development board based on FPGA, dual core processor's configuration for IMU\\/INS\\/GPS integrated navigation system is designed for experimental tests. The significant error
Airborne Antenna System for Minimum-Cycle-Slip GPS Reception
NASA Technical Reports Server (NTRS)
Wright, C. Wayne
A system that includes a Global Positioning System (GPS) antenna and associated apparatus for keeping the antenna aimed upward has been developed for use aboard a remote-sensing-survey airplane. The purpose served by the system is to enable minimum- cycle-slip reception of GPS signals used in precise computation of the trajectory of the airplane, without having to restrict the airplane to maneuvers that increase the flight time needed to perform a survey. Cycle slip signifies loss of continuous track of the phase of a signal. Minimum-cycle-slip reception is desirable because maintaining constant track of the phase of the carrier signal from each available GPS satellite is necessary for surveying to centimeter or subcentimeter precision. Even a loss of signal for as short a time as a nanosecond can cause cycle slip. Cycle slips degrade the quality and precision of survey data acquired during a flight. The two principal causes of cycle slip are weakness of signals and multipath propagation. Heretofore, it has been standard practice to mount a GPS antenna rigidly on top of an airplane, and the radiation pattern of the antenna is typically hemispherical, so that all GPS satellites above the horizon are viewed by the antenna during level flight. When the airplane must be banked for a turn or other maneuver, the reception hemisphere becomes correspondingly tilted; hence, the antenna no longer views satellites that may still be above the Earth horizon but are now below the equatorial plane of the tilted reception hemisphere. Moreover, part of the reception hemisphere (typically, on the inside of a turn) becomes pointed toward ground, with a consequent increase in received noise and, therefore, degradation of GPS measurements. To minimize the likelihood of loss of signal and cycle slip, bank angles of remote-sensing survey airplanes have generally been limited to 10 or less, resulting in skidding or slipping uncoordinated turns. An airplane must be banked in order to make a coordinated turn. For small-radius, short-time coordinated turns, it is necessary to employ banks as steep as 45 , and turns involving such banks are times and for confining airplanes as closely as possible to areas to be surveyed. The idea underlying the design is that if the antenna can be kept properly aimed, then the incidence of cycle slips caused by loss or weakness of signals can be minimized. The system includes an articulating GPS antenna and associated electronic circuitry mounted under a radome atop an airplane. The electronic circuitry includes a microprocessor-based interface-circuit-and-data-translation module. The system receives data on the current attitude of the airplane from the inertial navigation system of the airplane. The microprocessor decodes the attitude data and uses them to compute commands for the GPS-antenna-articulating mechanism to tilt the antenna, relative to the airplane, in opposition to the roll or bank of the airplane to keep the antenna pointed toward the zenith. The system was tested aboard the hurricane- hunting airplane of the National Oceanic and Atmospheric Administration (NOAA) [see figure] during an 11-hour flight to observe the landfall of Hurricane Bret in late summer of 1999. No bank-angle restrictions were imposed during the flight. Post-flight analysis of the GPS trajectory data revealed that no cycle slip had occurred.considered normal maneuvers. These steep banks are highly desirable for minimizing flight
Precise point positioning with the BeiDou navigation satellite system.
Li, Min; Qu, Lizhong; Zhao, Qile; Guo, Jing; Su, Xing; Li, Xiaotao
By the end of 2012, China had launched 16 BeiDou-2 navigation satellites that include six GEOs, five IGSOs and five MEOs. This has provided initial navigation and precise pointing services ability in the Asia-Pacific regions. In order to assess the navigation and positioning performance of the BeiDou-2 system, Wuhan University has built up a network of BeiDou Experimental Tracking Stations (BETS) around the World. The Position and Navigation Data Analyst (PANDA) software was modified to determine the orbits of BeiDou satellites and provide precise orbit and satellite clock bias products from the BeiDou satellite system for user applications. This article uses the BeiDou/GPS observations of the BeiDou Experimental Tracking Stations to realize the BeiDou and BeiDou/GPS static and kinematic precise point positioning (PPP). The result indicates that the precision of BeiDou static and kinematic PPP reaches centimeter level. The precision of BeiDou/GPS kinematic PPP solutions is improved significantly compared to that of BeiDou-only or GPS-only kinematic PPP solutions. The PPP convergence time also decreases with the use of combined BeiDou/GPS systems. PMID:24406856
75 FR 8928 - Announcement of IS-GPS-200, IS-GPS-705, IS-GPS-800 Interface Control Working Group (ICWG...
Federal Register 2010, 2011, 2012, 2013, 2014
...Positioning Systems Wing will be hosting an Interface Control Working Group (ICWG) teleconference...GPS Space Segment/Navigation User Interfaces), IS-GPS-705A (NAVSTAR GPS Space Segment/User Segment L5 Interfaces), and IS-GPS-800A...
Efficient authentication mechanisms for navigation systems a radio-navigation case
Stanford University
Global Positioning System (GPS) Laboratory. He is the Associate Investigator for the Stanford University is a research associate at the Stanford University Global Positioning System (GPS) Laboratory. He received his M
The purpose of this SOP is to describe the general procedures for the operation and initialization of the Magellan Global Positioning System (GPS) Satellite Navigator. This procedure was followed to ensure consistent data retrieval during the Arizona NHEXAS project and the Borde...
The MARCOR GPS mobile data system
NASA Astrophysics Data System (ADS)
Rothblatt, Martin
Market research revealed several key demands for an Automatic Vehicle Location (AVL) Global Positioning System (GPS) radio. The demands were for minimization of urban building blockage, easy programmability to minimize mobile data transmission costs, high accuracy for street map level coordination, interface capability with non-digital Specialized Mobile Radios (SMR), and a selling price close to that of alternatives such as Signposts and Loran-C. A team of experts was assembled to surmount these challenges and deliver a GPS radio for $500 to $1000, which operates at high accuracy in an urban environment and is plug-compatible with nearly all vehicle radios. Among the engineering and production breakthroughs described here are a unique Simultrac (Trademark) approach to satellite tracking, enabling up to eight GPS satellites to be used for position determination with a 2-channel receiver, and a receiver-in-a-microphone design. A powerful Application Specific Integrated Circuit (ASIC) allowed GPS to be brought within easy reach of millions of AVL users such as bus, taxi, and delivery vehicle fleets.
Design of Urban Nuclear Accident Emergency Command System Based on Intelligent Navigation
Yurong Yang; Xiangli Zheng
This paper takes the Shenzhen Emergency Command System as an example, then describes and discusses the construction methods and key technologies of the Urban Nuclear Accident Emergency Command System (UNAECS) based on intelligent navigation. This UNAECS adopts the GPS location technology based on space grid and the optimal path algorithm based on the maximum flow analysis, and realizes the dynamic
Simulation and analysis of differential GPS
NASA Technical Reports Server (NTRS)
Denaro, R. P.
NASA is conducting a research program to evaluate differential Global Positioning System (GPS) concepts for civil helicopter navigation. It is pointed out that the civil helicopter community will probably be an early user of GPS because of the unique mission operations in areas where precise navigation aids are not available. However, many of these applications involve accuracy requirements which cannot be satisfied by conventional GPS. Such applications include remote area search and rescue, offshore oil platform approach, remote area precision landing, and other precise navigation operations. Differential GPS provides a promising approach for meeting very demanding accuracy requirements. The considered procedure eliminates some of the common bias errors experienced by conventional GPS. This is done by making use of a second GPS receiver. A simulation process is developed as a tool for analyzing various scenarios of GPS-referenced civil aircraft navigation.
A comparative analysis of area navigation systems for general aviation
Dodge, Steven Malcolm
Within the next decade area navigation is to become the primary method of air navigation within the United States. There are numerous radio navigation systems that offer the capabilities of area navigation to general ...
Topex orbit determination using GPS tracking system
NASA Astrophysics Data System (ADS)
Rim, Hyung Jin
An extensive simulation study was performed to analyze several aspects of Topex Precise Orbit Determination (POD) using the Global Positioning System (GPS). Since the error modeling is the key to such an experiment, extensive investigation was performed based on real GPS data processing experience to create realistic measurement and dynamic error models for GPS. Double-differenced Topex-GPS phase measurements were evaluated in relation to improving the Earth geopotential model, which is the dominant error source for Topex POD. The effect of model errors on the Topex orbit and gravity recovery accuracies was evaluated. Long arc and short arc gravity solutions were compared to understand the effect of the model errors in using the long arc and the short arc solutions for the gravity recovery. Limiting factors for the long arc and the short arc gravity recovery were identified. The effect of ambiguity parameters on the gravity recovery was analyzed. Since the number of ambiguity parameters are quite large, an algorithm was developed to handle the ambiguity parameters more efficiently. Subarc parameters and empirical parameters were tested to find an optimal set of parameters to be estimated for the gravity recovery. Several gravity models were obtained by combining Topex-GPS information with a nominal geopotential information. These combined gravity models were evaluated by the statistical comparison of the recovered geopotential model parameters and by the Topex orbit analysis. Significant improvement in the nominal geopotential model, especially for the low degree harmonics, was achieved. More than a factor of three improvement in Topex orbit accuracy was demonstrated using the recovered gravity model. Analysis associated with predicted Topex radial orbit errors using the solution covariance indicates error estimates for the orbit accuracy is realistic.
Proceedings of 2011 NSF Engineering Research and Innovation Conference, Atlanta, Georgia Grant #0927475 Integration of Global Positioning System and Inertial Navigation for
Kamat, Vineet R.
#0927475 Integration of Global Positioning System and Inertial Navigation for Ubiquitous Context on the integration of Real Time Kinematic Global Positioning System (RTK-GPS) and Personal Dead Reckoning (PDR
BioGPS: navigating biological space to predict polypharmacology, off-targeting, and selectivity.
Siragusa, Lydia; Cross, Simon; Baroni, Massimo; Goracci, Laura; Cruciani, Gabriele
The structural comparison of protein binding sites is increasingly important in drug design; identifying structurally similar sites can be useful for techniques such as drug repurposing, and also in a polypharmacological approach to deliberately affect multiple targets in a disease pathway, or to explain unwanted off-target effects. Once similar sites are identified, identifying local differences can aid in the design of selectivity. Such an approach moves away from the classical "one target one drug" approach and toward a wider systems biology paradigm. Here, we report a semiautomated approach, called BioGPS, that is based on the software FLAP which combines GRID Molecular Interactions Fields (MIFs) and pharmacophoric fingerprints. BioGPS comprises the automatic preparation of protein structure data, identification of binding sites, and subsequent comparison by aligning the sites and directly comparing the MIFs. Chemometric approaches are included to reduce the complexity of the resulting data on large datasets, enabling focus on the most relevant information. Individual site similarities can be analyzed in terms of their Pharmacophoric Interaction Field (PIF) similarity, and importantly the differences in their PIFs can be extracted. Here we describe the BioGPS approach, and demonstrate its applicability to rationalize off-target effects (ER? and SERCA), to classify protein families and explain polypharmacology (ABL1 kinase and NQO2), and to rationalize selectivity between subfamilies (MAP kinases p38?/ERK2 and PPAR?/PPAR?). The examples shown demonstrate a significant validation of the method and illustrate the effectiveness of the approach. PMID:25556939
The Evolution of Global Positioning System (GPS) Technology.
ERIC Educational Resources Information Center
Kumar, Sameer; Moore, Kevin B.
Describes technological advances in the Global Positioning System (GPS), which is also known as the NAVSTAR GPS satellite constellation program developed in 1937, and changes in the nature of our world by GPS in the areas of agriculture, health, military, transportation, environment, wildlife biology, surveying and mapping, space applications, and�
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.
ION GPS '99, 14-17 September 1999, Nashville, TN Testing a GPS-based System for the Support of
Santerre, Rock
ION GPS '99, 14-17 September 1999, Nashville, TN Testing a GPS-based System for the Support of Ship as research professional on the GPS OTF project within the GEOIDE Network of Centres of Excellence of Geomatic Sciences at Laval University, where he conducts research and teaching in precise GPS static
Improving the Accuracy of Dynamic Localization Systems using RTK GPS by Identifying the GPS Latency
Denis Bouvet; Ga�tan Garcia
For precise localization of outdoor mobile robots, Real- Time Kinematic Global Positioning System (RTK GPS) has obvious advantages: position data are given with centimeter-accuracy, and the required infrastruc- ture is reduced to a sole fixed reference station. Yet, the use of this solution arises a number of issues, such as satellite maskings, or the existence of the so-called GPS latency
A Novel Data Fusion Approach in an Integrated GPS\\/INS System Using Adaptive Fuzzy Particle Filter
Ali Asadian; Behzad Moshiri; Ali Khaki Sedigh
In this paper we propose a new data fusion method based on particle filtering and fuzzy logic in order to adaptively integrate global positioning system and strapdown inertial navigation system (GPS\\/SDINS). This approach will reduce the dependence of the stable solution on stochastic properties of the system which is a function of vehicle dynamics and environmental conditions So the proposed
Fuel-Saving Navigation System in VANETs
Po-Yu Chen; Yi-Min Guo; Wen-Tsuen Chen
Because of shortage of raw materials, the energy-saving issues become popular in Vehicular Ad-hoc Networks (VANETs). A VANET is formed by traveling vehicles with communicating capability and thus it brings various applications. Navigation system is one of important applications in VANETs. The traditional navigation system usually plans a shortest path for users according to geographic maps but the planned path
Analysis of navigation performance for the Earth Observing System (EOS) using the TDRSS Onboard Navigation System (TONS)
NASA Technical Reports Server (NTRS)
Elrod, B.; Kapoor, A.; Folta, David C.; Liu, K.
Use of the Tracking and Data Relay Satellite System (TDRSS) Onboard Navigation System (TONS) was proposed as an alternative to the Global Positioning System (GPS) for supporting the Earth Observing System (EOS) mission. The results are presented of EOS navigation performance evaluation with respect to TONS based orbit, time, and frequency determination (OD/TD/FD). Two TONS modes are considered: one uses scheduled TDRSS forward link service to derive one way Doppler tracking data for OD/FD support (TONS-I); the other uses an unscheduled navigation beacon service (proposed for Advanced TDRSS) to obtain pseudorange and Doppler data for OD/TD/FD support (TONS-II). Key objectives of the analysis were to evaluate nominal performance and potential sensitivities, such as suboptimal tracking geometry, tracking contact scheduling, and modeling parameter selection. OD/TD/FD performance predictions are presented based on covariance and simulation analyses. EOS navigation scenarios and the contributions of principal error sources impacting performance are also described. The results indicate that a TONS mode can be configured to meet current and proposed EOS position accuracy requirements of 100 and 50 m, respectively.
Dennis M. Akos; Per-Ludvig Normark; Jeong-Taek Lee; Konstantin G. Gromov; James B. Y. Tsui; John Schamus; Wright-Patterson AFB
The ability to detect and process weak Global Navigation Satellite System (GNSS) signals is extremely valuable as the specified received power levels of such signals are already quite low. For example, the GPS-SPS signal specification indicates the signal power at the antenna will be -130 dBm. Such weak detection techniques would be of importance for a number of applications. This
Autonomous navigation system using a fuzzy adaptive nonlinear H? filter.
Outamazirt, Fariz; Li, Fu; Yan, Lin; Nemra, Abdelkrim
Although nonlinear H? (NH?) filters offer good performance without requiring assumptions concerning the characteristics of process and/or measurement noises, they still require additional tuning parameters that remain fixed and that need to be determined through trial and error. To address issues associated with NH? filters, a new SINS/GPS sensor fusion scheme known as the Fuzzy Adaptive Nonlinear H? (FANH?) filter is proposed for the Unmanned Aerial Vehicle (UAV) localization problem. Based on a real-time Fuzzy Inference System (FIS), the FANH? filter continually adjusts the higher order of the Taylor development thorough adaptive bounds �and adaptive disturbance attenuation , which significantly increases the UAV localization performance. The results obtained using the FANH? navigation filter are compared to the NH? navigation filter results and are validated using a 3D UAV flight scenario. The comparison proves the efficiency and robustness of the UAV localization process using the FANH? filter. PMID:25244587
Autonomous Navigation System Using a Fuzzy Adaptive Nonlinear H? Filter
Outamazirt, Fariz; Li, Fu; Yan, Lin; Nemra, Abdelkrim
Although nonlinear H? (NH?) filters offer good performance without requiring assumptions concerning the characteristics of process and/or measurement noises, they still require additional tuning parameters that remain fixed and that need to be determined through trial and error. To address issues associated with NH? filters, a new SINS/GPS sensor fusion scheme known as the Fuzzy Adaptive Nonlinear H? (FANH?) filter is proposed for the Unmanned Aerial Vehicle (UAV) localization problem. Based on a real-time Fuzzy Inference System (FIS), the FANH? filter continually adjusts the higher order of the Taylor development thorough adaptive bounds (?i) and adaptive disturbance attenuation (?), which significantly increases the UAV localization performance. The results obtained using the FANH? navigation filter are compared to the NH? navigation filter results and are validated using a 3D UAV flight scenario. The comparison proves the efficiency and robustness of the UAV localization process using the FANH? filter. PMID:25244587
GPS aiding of ocean current determination. [Global Positioning System
NASA Technical Reports Server (NTRS)
Mohan, S. N.
The navigational accuracy of an oceangoing vessel using conventional GPS p-code data is examined. The GPS signal is transmitted over two carrier frequencies in the L-band at 1575.42 and 1227.6 MHz. Achievable navigational uncertainties of differenced positional estimates are presented as a function of the parameters of the problem, with particular attention given to the effect of sea-state, user equivalent range error, uncompensated antenna motion, varying delay intervals, and reduced data rate examined in the unaided mode. The unmodeled errors resulting from satellite ephemeris uncertainties are shown to be negligible for the GPS-NDS (Navigation Development) satellites. Requirements are met in relatively calm seas, but accuracy degradation by a factor of at least 2 must be anticipated in heavier sea states. The aided mode of operation is examined, and it is shown that requirements can be met by using an inertial measurement unit (IMU) to aid the GPS receiver operation. Since the use of an IMU would mean higher costs, direct Doppler from the GPS satellites is presented as a viable alternative.
NASA Astrophysics Data System (ADS)
Lawrence, David Gary
The advent of the Global Positioning System (GPS) is revolutionizing the field of navigation. Commercial aviation has been particularly influenced by this worldwide navigation system. From ground vehicle guidance to aircraft landing applications, GPS has the potential to impact many areas of aviation. GPS is already being used for non-precision approach guidance; current research focuses on its application to more critical regimes of flight. To this end, the following contributions were made: (1) Development of algorithms and a flexible software architecture capable of providing real-time position solutions accurate to the centimeter level with high integrity. This architecture was used to demonstrate 110 automatic landings of a Boeing 737. (2) Assessment of the navigation performance provided by two GPS-based landing systems developed at Stanford, the Integrity Beacon Landing System, and the Wide Area Augmentation System. (3) Preliminary evaluation of proposed enhancements to traditional techniques for GPS positioning, specifically, dual antenna positioning and pseudolite augmentation. (4) Introduction of a new concept for positioning using airport pseudolites. The results of this research are promising, showing that GPS-based systems can potentially meet even the stringent requirements of a Category III (zero visibility) landing system. Although technical and logistical hurdles still exist, it is likely that GPS will soon provide aircraft guidance in all phases of flight, including automatic landing, roll-out, and taxi.
A wellbore inertial navigation system
Kelsey, J.R.
A prototype wireline tool which includes a downhole inertial platform and a surface computer to spatially map a well is described. The hardware consists of a single-gimballed inertial platform with accelerometers and gyros to obtain three-axis motion information. The gyroscope and accelerometer outputs are transmitted to a computer at the surface which calculates probe attitude relative to north, east, and vertical. Double integration of the accelerometer data provides the position information. A conventional 7-conductor wireline is used for the system data transmission. System accuracy is enhanced by advances made in the computer software which processes the data received from the tool. The software uses statistical sampling estimation to obtain optimal estimates of the system errors. Measurement errors are determined by periodically stopping the tool during the logging procedure and observing the indicated velocity measurements. This procedure, known as Kalman filtering, results in increased accuracy of the data. Present mapping systems have an X-Y-Z location accuracy of 100 to 200 feet for a typical well depth of 10,000 feet. Test results show that the new system is accurate to about 1 foot per 1000 feet of well depth. Unlike conventional systems, the inertial navigator does not require any sort of projection of the cable length (which may not be accurately known). Also, this system provides continuous data throughout the wellbore and logging speeds on the order of 10 ft/sec appear possible. The hardware and software associated with this mapping system are described and the recent field test results are reported.
Hydrographic surveying of reservoirs using differential GPS navigation and GIS data analysis
White, C.O. [Pacific Gas and Electric Co., San Ramon, CA (United States)
In 1993 and 1994, the Pacific Gas and Electric Company (PG&E) conducted hydrographic surveys on their Rock Creek and Cresta reservoirs. PG&E`s Rock Creek and Cresta reservoirs are located on the North Fork of the Feather River in northern California. Hydrographic surveys were conducted to determine sedimentation levels in the two reservoirs. This paper outlines PG&E`s efforts to monitor sedimentation levels from year-to-year. A survey-grade recording fathometer was used to record the reservoir depths. Survey vessel location was monitored using a Global Positioning System (GPS). Bathymetric contours and reservoir volumes were calculated using a Geographic Information System (GIS). This paper presents the methodology, results, and limitations of this technique for conducting hydrographic surveys. The results of the 1993 and 1994 hydrographic surveys and comparisons to a 1986 photogrammetric survey when the reservoirs were completely drawn down are presented. It is concluded that the GPS hydrographic survey methodology is an accurate and cost effective technique to monitor and address the long-term sediment balance in the reservoirs.
Ladkin, Peter B.
-based system using signals provided by the Department of Defense's Global Positioning System (GPS). However-jam technologies. KEYWORDS: National Airspace System Global Positioning System Navigation #12;v TABLE OF CONTENTS
Transit - The first navigational satellite system
G. Richards
The Transit navigational satellite system, providing fixes of high accuracy for ships, is discussed. The Transit satellite, with an orbit of about 1100 km, uses a radio-Doppler navigation method in which the ship's position is calculated from the observed change in the received frequency of the satellite's radio transmissions. The satellite carries an ultra-stable oscillator to control the transmitter frequency,
Relative navigation requirements for automatic rendezvous and capture systems
Peter M. Kachmar; Robert J. Polutchko; William Chu; Moises Montez
This paper will discuss in detail the relative navigation system requirements and sensor trade-offs for Automatic Rendezvous and Capture. Rendezvous navigation filter development will be discussed in the context of navigation performance requirements for a 'Phase One' AR&C system capability. Navigation system architectures and the resulting relative navigation performance for both cooperative and uncooperative target vehicles will be assessed. Relative
Civil satellite navigation and location systems
NASA Astrophysics Data System (ADS)
Blanchard, W. F.
The use of satellites for civil navigation and location, including satellites not necessarily launched for that purpose, is reviewed. In particular, attention is given to differences between civil and military satellites; civil use of military systems and the associated commercial considerations and regulatory issues; the use of communication satellites; and radiodetermination satellite service based on geostationary satellites. The discussion also covers integration with ground-based radio-navigation systems; existing radio-navigation satellite systems; and the Starfix, Geostar/Locstar, Starfind, Navsat, and Rexstar systems.
Constrained navigation for unmanned systems
NASA Astrophysics Data System (ADS)
Vasseur, Laurent; Gosset, Philippe; Carpentier, Luc; Marion, Vincent; Morillon, Joel G.; Ropars, Patrice
The French Military Robotic Study Program (introduced in Aerosense 2003), sponsored by the French Defense Procurement Agency and managed by Thales as the prime contractor, focuses on about 15 robotic themes which can provide an immediate "operational add-on value". The paper details the "constrained navigation" study (named TEL2), which main goal is to identify and test a well-balanced task sharing between man and machine to accomplish a robotic task that cannot be performed autonomously at the moment because of technological limitations. The chosen function is "obstacle avoidance" on rough ground and quite high speed (40 km/h). State of the art algorithms have been implemented to perform autonomous obstacle avoidance and following of forest borders, using scanner laser sensor and standard localization functions. Such an "obstacle avoidance" function works well most of the time, BUT fails sometimes. The study analyzed how the remote operator can manage such failures so that the system remains fully operationally reliable; he can act according to two ways: a) finely adjust the vehicle current heading; b) take the control of the vehicle "on the fly" (without stopping) and bring it back to autonomous behavior when motion is secured again. The paper also presents the results got from the military acceptance tests performed on French 4x4 DARDS ATD.
The transmission link of CAPS navigation and communication system
NASA Astrophysics Data System (ADS)
Cui, Junxia; Shi, Huli; Chen, Jibin; Pei, Jun
The Chinese Area Positioning System (CAPS) is based on communication satellites with integrated capability, which is different from the Global Positioning System (GPS), the International Maritime Satellite Organization (Inmarsat) and so on. CAPS works at C-band, and its navigation information is not directly generated from the satellite, but from the master control station on the ground and transmitted to users via the satellite. The slightly inclined geostationary-satellite orbit (SIGSO) satellites are adopted in CAPS. All of these increase the difficulty in the design of the system and terminals. In this paper, the authors study the CAPS configuration parameters of the navigation master control station, information transmission capability, and the selection of the antenna aperture of the communication center station, as well as the impact of satellite parameters on the whole communication system from the perspective of the transmission link budget. The conclusion of availability of the CAPS navigation system is achieved. The results show that the CAPS inbound communication system forms a new low-data-rate satellite communication system, which can accommodate mass communication terminals with the transmission rate of no more than 1 kbps for every terminal. The communication center station should be configured with a large-aperture antenna (about 10-15 m); spread spectrum communication technology should be used with the spreading gain as high as about 40 dB; reduction of the satellite transponder gain attenuation is beneficial to improving the signal-to-noise ratio of the system, with the attenuation value of 0 or 2 dB as the best choice. The fact that the CAPS navigation system has been checked and accepted by the experts and the operation is stable till now clarifies the rationality of the analysis results. The fact that a variety of experiments and applications of the satellite communication system designed according to the findings in this paper have been successfully carried out confirms the correctness of the study results.
GPS-based system for satellite tracking and geodesy
NASA Astrophysics Data System (ADS)
Bertiger, Willy I.; Thornton, Catherine L.
High-performance receivers and data processing systems developed for GPS are reviewed. The GPS Inferred Positioning System (GIPSY) and the Orbiter Analysis and Simulation Software (OASIS) are described. The OASIS software is used to assess GPS system performance using GIPSY for data processing. Consideration is given to parameter estimation for multiday arcs, orbit repeatability, orbit prediction, daily baseline repeatability, agreement with VLBI, and ambiguity resolution. Also, the dual-frequency Rogue receiver, which can track up to eight GPS satellites simultaneously, is discussed.
Positional Accuracy of Airborne Integrated Global Positioning and Inertial Navigation Systems for Mapping in Glen Canyon, Arizona
Sanchez, Richard D.; Hothem, Larry D.
High-resolution airborne and satellite image sensor systems integrated with onboard data collection based on the Global Positioning System (GPS) and inertial navigation systems (INS) may offer a quick and cost-effective way to gather accurate topographic map information without ground control or aerial triangulation. The Applanix Corporation?s Position and Orientation Solutions for Direct Georeferencing of aerial photography was used in this project to examine the positional accuracy of integrated GPS/INS for terrain mapping in Glen Canyon, Arizona. The research application in this study yielded important information on the usefulness and limits of airborne integrated GPS/INS data-capture systems for mapping.
Post-disposal orbital evolution of satellites and upper stages used by the GPS and GLONASS navigation constellations: The long-term impact on the Medium Earth Orbit environment
NASA Astrophysics Data System (ADS)
Pardini, Carmen; Anselmo, Luciano
The long-term evolution and environmental impact in MEO of all the abandoned spacecraft and upper stages associated with the GPS and GLONASS navigation constellations were analyzed. The orbits of the disposed objects, as of 1 May 2011, were propagated for 200 years and snapshots of their evolving distribution were obtained, together with an estimation of the changing collision probability with the spacecraft of the operational navigation systems existing or planned in MEO, i.e., GLONASS, GPS, Beidou and Galileo. The probability that the abandoned objects considered will collide with the operational spacecraft of the navigation constellations is very low, even taking into account the intrinsic eccentricity instability of the disposal orbits. Assuming the present or envisaged configuration of the constellations in MEO, the probability of collision, integrated over 200 years, would be <1/300 with a GLONASS spacecraft, <1/15,000 with a GPS or Beidou spacecraft, and <1/250,000 with a Galileo spacecraft. The worst disposal strategy consists in abandoning satellites and upper stages close to the altitude of the operational constellation (GLONASS), while a re-orbiting a few hundred km away (GPS) is able to guarantee an effective long-term dilution of the collision risk, irrespective of the eccentricity instability due to geopotential and luni-solar perturbations. The disposal strategies applied so far to the GPS satellites should be able to guarantee for at least a few centuries a sustainable MEO environment free of collisions among intact objects. Consequently, there would be no need to adopt disposal schemes targeting also the optimal value of the eccentricity vector. However, it should be pointed out that the GPS disposal strategy was devised well in advance of the Beidou constellation announcement, so most of the abandoned satellites were re-orbited fairly close to the altitude of the new Chinese system. A new re-orbiting approach will be therefore needed in the future.
Satellite Navigation Systems in the Transport, Today and in the Future
NASA Astrophysics Data System (ADS)
Januszewski, Jacek
Operational status and practical exploitation (October 2010) of Satellite Navigation Systems (SNS), as GPS and GLONASS, and Satellite Based Augmentation System (SBAS), as EGNOS are presented in this paper. Other SNS are under development as Galileo and Compass, other SBAS in various part of the world are already available (WAAS, MSAS) or under development as GAGAN or SDCM. The receivers of these systems are now found in every mode of transportation - air, maritime and land. Additionally SNS markets and applications in the transport and the most significant events in the satellite navigation systems in the nearest years and SNS markets and applications are described also.
Time and Frequency Measurements Using the Global Positioning System (GPS)
Michael A. Lombardi; Lisa M. Nelson; Andrew N. Novick; Victor S. Zhang
This paper describes how Global Positioning System (GPS) satellite signals are used in time and frequency metrology. It discusses how a GPS receiver can provide a reference signal for frequency calibrations and time synchronization. It also explains the several types of time and frequency measurements that utilize GPS signals. These include one-way or direct reception measurements, single and multi-channel common-view
MIC2005: The Sixth Metaheuristics International Conference ??1 E#cient Tabu Search Procedures for the GPS Surveying
Fidanova, Stefka
for the GPS Surveying Stefka Fidanova # Hussain A. Saleh + # IPP -- BAS, Acad. G. Bonchev str. bl.25A, 1113 System (GPS), the Russian GLObal Navigation Satellite System (GLONASS), and the forthcoming Euro� pean Satellite Navigation System (GALILEO). In this paper, it is the use of GPS to establish surveying networks
Application of GPS based fault location scheme for distribution system
Z. Q. Bo; G. Weller; F. Jiang; Q. X. Yang
This paper presents the application of transient based fault location techniques to the distribution system by utilising the Global Positioning System (GPS). In the scheme, the proposed locator, which contains a specially designed fault transient detection device, a GPS receiver, is connected to the power line through a coupling capacitor. The locator installed at each busbar in a distribution network
Formations of Autonomous Vehicles Using Global Positioning Systems (GPS)
Arabshahi, Payman
Formations of Autonomous Vehicles Using Global Positioning Systems (GPS) Kourosh Rahnamai; Kevin--In this work we present the design, development, and testing of a hardware testbed for formation movement, using a fleet of autonomous R/C (Remote Control) vehicles equipped with Global Positioning Systems (GPS
Performance of Hybrid Positioning System Combining GPS and Television Signals
Stanford University
the benefits of a hybrid positioning system combining GPS and television signals, a prototype of TV signalPerformance of Hybrid Positioning System Combining GPS and Television Signals Ju-Yong Do Electrical solutions to this problem is the adoption of powerful terrestrial signals such as television, Wi
INTERACTION DESIGN ISSUES FOR CAR NAVIGATION SYSTEMS Paul Curzon
Curzon, Paul
of in- car navigation systems. It focused on a commercial product. Critical incident analysisINTERACTION DESIGN ISSUES FOR CAR NAVIGATION SYSTEMS Paul Curzon Middlesex University Interaction the interaction design of car navigation systems. Keywords In-car navigation systems, cognitive walkthrough. 1
Landslide monitoring using multi-antenna GPS deformation monitoring system
NASA Astrophysics Data System (ADS)
Yeh, T.; Hu, Y.; Ding, X.; Chen, C.
GPS has already widely applied in civil engineering, fault detecting and landslide monitoring in the last decade, because of its convenience and high precision. However, GPS receiver is very expensive. If we want to monitor the landslide twenty-four hours a day, we need to buy a lot of GPS receivers. In order to spend less cost, multi- antenna GPS deformation monitoring system was employed to monitor the landslide of the freeway at Guansi section in Taiwan. Moreover, the data from 3D laser scanner, rain gauge, inclinometer and water table meter were utilized to analysis the movement of this landslide to make sure the safety of the drivers.
Hardware-in-the-loop simulations of GPS-based navigation and control for satellite formation flying
NASA Astrophysics Data System (ADS)
Park, Jae-Ik; Park, Han-Earl; Park, Sang-Young; Choi, Kyu-Hong
A relative navigation and formation control algorithm for satellite formation flying was developed, and a hardware-in-the-loop (HIL) simulation testbed was established and configured to evaluate this algorithm. The algorithm presented is a relative navigation estimation algorithm using double-difference carrier-phase and single-difference code measurements based on the extended Kalman filter (EKF). In addition, a state-dependent Riccati equation (SDRE) technique is utilized as a nonlinear controller for the formation control problem. The state-dependent coefficient (SDC) form is formulated to include nonlinearities in the relative dynamics. To evaluate the relative navigation and control algorithms developed, a closed-loop HIL testbed is configured. To demonstrate the performance of the testbed, a test formation flying scenario comprising formation acquisition and keeping in a low earth orbit (LEO) has been established. The relative navigation results from the closed-loop simulations show that a 3D RMS of 0.07 m can be achieved for position accuracy. The targeted leader-follower formation flying in the along-track separation of 100 m was maintained with a mean position error of approximately 0.2 m and a standard deviation of 0.9 m. The simulation results show that the HIL testbed is capable of successful demonstration of the GPS-based satellite autonomous formation flying mission.
Results from a GPS Shuttle Training Aircraft flight test
Penny E. Saunders; Moises N. Montez; Michael C. Robel; David N. Feuerstein; Mike E. Aerni; S. Sangchat; Lon M. Rater; Scott P. Cryan; Lydia R. Salazar; Mark P. Leach
A series of Global Positioning System (GPS) flight tests were performed on a National Aeronautics and Space Administration's (NASA's) Shuttle Training Aircraft (STA). The objective of the tests was to evaluate the performance of GPS-based navigation during simulated Shuttle approach and landings for possible replacement of the current Shuttle landing navigation aid, the Microwave Scanning Beam Landing System (MSBLS). In
Recent Advances in Realizing the Terrestrial Reference System from GPS
NASA Astrophysics Data System (ADS)
Haines, B. J.; Bertiger, W.; Desai, S. D.; Harvey, N.; Sibois, A.; Weiss, J. P.
The Global Positioning System (GPS) plays an important role in both realizing and disseminating the International Terrestrial Reference Frame (ITRF). Driven by both economy and convenience, geodetic-quality GPS receivers have been dispersed throughout the globe and provide the only basis of measurement at many of the sites underlying the ITRF. Through site collocations, GPS also provides crucial ties among the tracking antennas supporting other space-geodetic techniques (SLR, VLBI and DORIS). Due to misgivings about the absolute geocentric accuracy of the GPS system at the cm level, however, GPS data have been excluded from direct determination of both the origin and scale of the ITRF. We report on recent advances in determining the origin and scale of the TRF based on GPS data alone. These advances have been made possible by the development of new GPS measurements models, most notably for the phase- and group-delay variations of the GPS satellite antennas. The resulting TRF determinations provide an independent means of assessing the current (2008) version of the ITRF. Finally, the results help lay the groundwork for a potential expansion of the role of GPS in defining and maintaining the ITRF at the level necessary to support the most demanding applications (e.g. measuring global sea-level change). Based on 18 years of data (1994-2012), our current GPS-defined frame agrees with ITRF2008 to 0.2 and 0.7 mm/yr in terms of scale and origin (3D) rate respectively. We update our GPS solutions by extending the analysis to two decades (1993-2013) and exploiting recent advances in the solution strategy. The weekly network solutions underlying the frame definition now feature high-frequency (every 2-hr) estimates of both pole position and UT1-UTC. We discuss results from these estimates, and describe the stability of the GPS frame realization. Finally, we consider possible origins of a remaining scale bias.
GPS Bibliography by the National Geodetic Survey
NSDL National Science Digital Library
This bibliography, intended for more advanced users, is a compilation of peer-reviewed articles published in 2006 describing original research with citations on Global Positioning Systems (GPS) and Global Satellite Navigation Systems (GNSS).
The Role of Trust and Interaction in GPS Related Accidents: A Human Factors Safety Assessment of the Global Positioning System (GPS)
Johnson, Chris
of the Global Positioning System (GPS) Chris. W. Johnson, DPhil; Department of Computing Science, University; accident analysis; organisational safety. Abstract The Global Positioning System (GPS) uses a network
Study of spatial and temporal characteristics of L-band scintillations over the Indian low-latitude region and their possible effects on GPS navigation
NASA Astrophysics Data System (ADS)
Rama Rao, P. V. S.; Gopi Krishna, S.; Niranjan, K.; Prasad, D. S. V. V. D.
The scintillation data (S4-index) at the L-band frequency of 1.575GHz, recorded from a total of 18 GPS receivers installed at different locations in India under the GAGAN project, have provided us with a unique opportunity, for the first time in the Indian region, to make a simultaneous study of spatio-temporal and intensity characteristics of the trans-ionospheric scintillations during the 18-month, low sunspot activity (LSSA) period from January 2004 to July 2005. During this period, the occurrence of scintillations is found to be maximum around the pre-midnight hours of equinox months, with very little activity during the post-midnight hours. No significant scintillation activity is observed during the summer and winter months of the period of observation. The intensity (S4 index) of the scintillation activity is stronger around the equatorial ionization anomaly (EIA) region in the geographic latitude range of 15� to 25� N in the Indian region. These scintillations are often accompanied by the TEC depletions with durations ranging from 5 to 25 min and magnitudes from 5 to 15 TEC units which affect the positional accuracy of the GPS by 1 to 3 m. Further, during the intense scintillation events (S4>0.45?10 dB), the GPS receiver is found to lose its lock for a short duration of 1 to 4 min, increasing the error bounds effecting the integrity of the SBAS operation. During the present period of study, a total of 395 loss of lock events are observed in the Indian EIA region; this number is likely to increase during the high sunspot activity (HSSA) period, creating more adverse conditions for the trans-ionospheric communications and the GPS-based navigation systems.
Autonomous Vehicle Positioning with GPS in Urban Canyon Environments
Youjing Cui; Shuzhi S. Ge
Abstract�The Global Positioning System (GPS) has been widely used in land vehicle navigation applications. However, the posi- tioning systems based on GPS alone face great problems in the so-called urban canyon environments, where the GPS signals are often blocked by highrise buildings and there are not enough avail- able satellite signals to estimate the positioning information of a fix. To
Global navigation satellite system receiver for weak signals under all dynamic conditions
NASA Astrophysics Data System (ADS)
Ziedan, Nesreen Ibrahim
The ability of the Global Navigation Satellite System (GNSS) receiver to work under weak signal and various dynamic conditions is required in some applications. For example, to provide a positioning capability in wireless devices, or orbit determination of Geostationary and high Earth orbit satellites. This dissertation develops Global Positioning System (GPS) receiver algorithms for such applications. Fifteen algorithms are developed for the GPS C/A signal. They cover all the receiver main functions, which include acquisition, fine acquisition, bit synchronization, code and carrier tracking, and navigation message decoding. They are integrated together, and they can be used in any software GPS receiver. They also can be modified to fit any other GPS or GNSS signals. The algorithms have new capabilities. The processing and memory requirements are considered in the design to allow the algorithms to fit the limited resources of some applications; they do not require any assisting information. Weak signals can be acquired in the presence of strong interfering signals and under high dynamic conditions. The fine acquisition, bit synchronization, and tracking algorithms are based on the Viterbi algorithm and Extended Kalman filter approaches. The tracking algorithms capabilities increase the time to lose lock. They have the ability to adaptively change the integration length and the code delay separation. More than one code delay separation can be used in the same time. Large tracking errors can be detected and then corrected by a re-initialization and an acquisition-like algorithms. Detecting the navigation message is needed to increase the coherent integration; decoding it is needed to calculate the navigation solution. The decoding algorithm utilizes the message structure to enable its decoding for signals with high Bit Error Rate. The algorithms are demonstrated using simulated GPS C/A code signals, and TCXO clocks. The results have shown the algorithms ability to reliably work with 15 dB-Hz signals and acceleration over 6 g.
Space shuttle navigation analysis
NASA Technical Reports Server (NTRS)
Jones, H. L.; Luders, G.; Matchett, G. A.; Sciabarrasi, J. E.
A detailed analysis of space shuttle navigation for each of the major mission phases is presented. A covariance analysis program for prelaunch IMU calibration and alignment for the orbital flight tests (OFT) is described, and a partial error budget is presented. The ascent, orbital operations and deorbit maneuver study considered GPS-aided inertial navigation in the Phase III GPS (1984+) time frame. The entry and landing study evaluated navigation performance for the OFT baseline system. Detailed error budgets and sensitivity analyses are provided for both the ascent and entry studies.
Navigation of robotic system using cricket motes
NASA Astrophysics Data System (ADS)
Patil, Yogendra J.; Baine, Nicholas A.; Rattan, Kuldip S.
This paper presents a novel algorithm for self-mapping of the cricket motes that can be used for indoor navigation of autonomous robotic systems. The cricket system is a wireless sensor network that can provide indoor localization service to its user via acoustic ranging techniques. The behavior of the ultrasonic transducer on the cricket mote is studied and the regions where satisfactorily distance measurements can be obtained are recorded. Placing the motes in these regions results fine-grain mapping of the cricket motes. Trilateration is used to obtain a rigid coordinate system, but is insufficient if the network is to be used for navigation. A modified SLAM algorithm is applied to overcome the shortcomings of trilateration. Finally, the self-mapped cricket motes can be used for navigation of autonomous robotic systems in an indoor location.
The International GPS Service: Celebrating the 10th anniversary and looking to the next decade
J. M. Dow; R. E. Neilan; G. Gendt
After 10 years as a service of the International Association of Geodesy, the International GPS Service IGS is preparing for the future use of multiple integrated global navigation satellite systems: GPS and its modernisation, Galileo and GLONASS. Since 1994, the IGS produces GPS data and products at the highest level of precision and accuracy available anywhere: it provides GPS orbits
Flight-control/navigation inertial reference system
NASA Technical Reports Server (NTRS)
Ebner, R. E.
The preliminary design of a redundant strapdown navigation system for integrated flight-control/navigation use has been completed. Based on application of tuned-gimbal gyros, a compact configuration (13 in x 13 in x 14 in) has been achieved for fail-operational/fail-operational redundancy. Test data are presented for strapdown system test programs including flight testing of the LN-50 tuned-gimbal gyro system. Testing of a redundant sensor configuration is currently in process. Strapdown gyro development also includes ring laser and nuclear magnetic resonance techniques.
Limitations of Pseudolite Systems Using Off-The-Shelf GPS Receivers
Mustafa Ozgur Kanli
Pseudolites (PLs) are ground-based transmitters that transmit GPS-like signals. They have been used to test GPS system elements and to enhance GPS in certain applications by providing better accuracy, integrity and availability through the use of PL signals in addition to the GPS signals. PLs are also a promising technology for providing positioning in indoor, high multipath environments where GPS
Multisensor navigation system for an autonomous helicopter
Joerg S. Dittrich; Eric N. Johnson
Autonomous unmanned aerial vehicles (UAVs) require avionics systems that enable them to maintain a stable attitude and to follow a desired flight path. This paper considers the design and development of such an avionics system that provides navigational and terrain information to the flight computer of a rotorcraft UAV. The process includes the design and testing of flight hardware and
Sensing the Earth using Global Navigation Satellite System signals
NASA Astrophysics Data System (ADS)
Jin, Shuanggen; Rizos, Chris; Rius, Antonio
International Workshop on GNSS Remote Sensing for Future Missions and Sciences; Shanghai, China, 7-9 August 2011 The Global Navigation Satellite System (GNSS) has been widely used in navigation, positioning, and geoscience applications. Recently, the versatility of GNSS as a new remote sensing tool has been demonstrated with the use of refracted, reflected, and scattered GNSS signals to sound the atmosphere and ionosphere, ocean, land surfaces (including soil moisture), and cryosphere. Existing GPS radio occultation (RO) missions�e.g., the U.S.-Argentina SAC-C, German Challenging Minisatellite Payload (CHAMP), U.S.-Germany Gravity Recovery and Climate Experiment (GRACE), Taiwan-U.S. Formosa Satellite Mission-3/Constellation Observing System for Meteorology, Ionosphere, and Climate (FORMOSAT-3/COSMIC) satellites, German TerraSAR-X satellite, and European MetOp�together with groundbased GNSS observations, have provided precise and high-resolution information on tropospheric water vapor, pressure, temperature, tropopause parameters, ionospheric total electron content, and electron density profiles. GNSS signals reflected from the ocean and land surface can determine the ocean height, ocean surface wind speed and wind direction, soil moisture, and ice and snow thickness. With improvement expected due to the next generation of multifrequency GNSS systems and receivers, and new space-based instruments tracking GNSS reflected and refracted signals, new scientific applications of GNSS are expected in the near future across a number of environmental remote sensing fields.
Meta-image navigation augmenters for unmanned aircraft systems (MINA for UAS)
NASA Astrophysics Data System (ADS)
Ҫelik, Koray; Somani, Arun K.; Schnaufer, Bernard; Hwang, Patrick Y.; McGraw, Gary A.; Nadke, Jeremy
GPS is a critical sensor for Unmanned Aircraft Systems (UASs) due to its accuracy, global coverage and small hardware footprint, but is subject to denial due to signal blockage or RF interference. When GPS is unavailable, position, velocity and attitude (PVA) performance from other inertial and air data sensors is not sufficient, especially for small UASs. Recently, image-based navigation algorithms have been developed to address GPS outages for UASs, since most of these platforms already include a camera as standard equipage. Performing absolute navigation with real-time aerial images requires georeferenced data, either images or landmarks, as a reference. Georeferenced imagery is readily available today, but requires a large amount of storage, whereas collections of discrete landmarks are compact but must be generated by pre-processing. An alternative, compact source of georeferenced data having large coverage area is open source vector maps from which meta-objects can be extracted for matching against real-time acquired imagery. We have developed a novel, automated approach called MINA (Meta Image Navigation Augmenters), which is a synergy of machine-vision and machine-learning algorithms for map aided navigation. As opposed to existing image map matching algorithms, MINA utilizes publicly available open-source geo-referenced vector map data, such as OpenStreetMap, in conjunction with real-time optical imagery from an on-board, monocular camera to augment the UAS navigation computer when GPS is not available. The MINA approach has been experimentally validated with both actual flight data and flight simulation data and results are presented in the paper.
Hybrid GPS-GSM Localization of Automobile Tracking System
Al-Khedher, Mohammad A
An integrated GPS-GSM system is proposed to track vehicles using Google Earth application. The remote module has a GPS mounted on the moving vehicle to identify its current position, and to be transferred by GSM with other parameters acquired by the automobile's data port as an SMS to a recipient station. The received GPS coordinates are filtered using a Kalman filter to enhance the accuracy of measured position. After data processing, Google Earth application is used to view the current location and status of each vehicle. This goal of this system is to manage fleet, police automobiles distribution and car theft cautions.
High-Speed and Real-Time Communication Controller for Embedded Integrated Navigation System
Zhang Guolong; Xu Xiaosu
To meet the complex requirements of the miniature embedded integrated (INS\\/GPS) navigation system based on DSP, all peripheral circuits were integrated in single chip of FPGA, such as logic control module, serial\\/parallel data conversion and FIFO(First In First Out), etc. The multi-channel UART(Universal Asynchronous Receiver Transmitter) consists of the data conversion circuit and FIFO. In addition, the ping-pong buffer storages
Another pilot reported that he used GPS successfully to navigate to a distant point on an IFR flight plan but ran
Another pilot reported that he used GPS successfully to navigate to a distant point on an IFR flight plan but ran afoul of the FARs in the process: s IFR flight plan filed on airways [with dangerous occurred. Conditions CAVU, VMC, continuous radar contact. IFR equipment rules apply to all
Balloon gravimetry using GPS and INS
Christopher Jekeli; Hanscom AFB
Measurement of the horizontal components of gravity at altitude using balloon-borne instrumentation consisting of a Global Positioning System (GPS) receiver and a strapdown inertial navigation system (INS) is discussed. GPS data are to be used primarily to determine the total inertial acceleration of the balloon, while the INS accelerometers sense all nongravitational accelerations. A covariance analysis based on the Kalman
A Comparison between Different Error Modeling of MEMS Applied to GPS/INS Integrated Systems
Quinchia, Alex G.; Falco, Gianluca; Falletti, Emanuela; Dovis, Fabio; Ferrer, Carles
Advances in the development of micro-electromechanical systems (MEMS) have made possible the fabrication of cheap and small dimension accelerometers and gyroscopes, which are being used in many applications where the global positioning system (GPS) and the inertial navigation system (INS) integration is carried out, i.e., identifying track defects, terrestrial and pedestrian navigation, unmanned aerial vehicles (UAVs), stabilization of many platforms, etc. Although these MEMS sensors are low-cost, they present different errors, which degrade the accuracy of the navigation systems in a short period of time. Therefore, a suitable modeling of these errors is necessary in order to minimize them and, consequently, improve the system performance. In this work, the most used techniques currently to analyze the stochastic errors that affect these sensors are shown and compared: we examine in detail the autocorrelation, the Allan variance (AV) and the power spectral density (PSD) techniques. Subsequently, an analysis and modeling of the inertial sensors, which combines autoregressive (AR) filters and wavelet de-noising, is also achieved. Since a low-cost INS (MEMS grade) presents error sources with short-term (high-frequency) and long-term (low-frequency) components, we introduce a method that compensates for these error terms by doing a complete analysis of Allan variance, wavelet de-nosing and the selection of the level of decomposition for a suitable combination between these techniques. Eventually, in order to assess the stochastic models obtained with these techniques, the Extended Kalman Filter (EKF) of a loosely-coupled GPS/INS integration strategy is augmented with different states. Results show a comparison between the proposed method and the traditional sensor error models under GPS signal blockages using real data collected in urban roadways. PMID:23887084
Design of gyroscope-free navigation systems
Chin-Woo Tan; K. Mostov; P. Varaiya
We examine the feasibility of designing a gyroscope-free inertial navigation system (INS) that uses only accelerometers to compute the linear and angular motions of a rigid body. The accelerometer output equation is derived to relate the linear and angular motions of a rigid body relative to a fixed inertial frame. A sufficient condition is given to determine if a configuration
Pre-Flight Testing of Spaceborne GPS Receivers Using a GPS Constellation Simulator
NASA Technical Reports Server (NTRS)
Kizhner, Semion; Davis, Edward; Alonso, Roberto
The NASA Goddard Space Flight Center (GSFC) Global Positioning System (GPS) applications test facility has been established within the GSFC Guidance Navigation and Control Center. The GPS test facility is currently housing the Global Simulation Systems Inc. (GSSI) STR2760 GPS satellite 40-channel attitude simulator and a STR4760 12-channel navigation simulator. The facility also contains a few other resources such as an atomic time standard test bed, a rooftop antenna platform and a radome. It provides a new capability for high dynamics GPS simulations of space flight that is unique within the aerospace community. The GPS facility provides a critical element for the development and testing of GPS based technologies i.e. position, attitude and precise time determination used on-board a spacecraft, suborbital rocket or balloon. The GPS simulator system is configured in a transportable rack and is available for GPS component development as well as for component, spacecraft subsystem and system level testing at spacecraft integration and test sites. The GPS facility has been operational since early 1996 and has been utilized by space flight projects carrying GPS experiments, such as the OrbView-2 and the Argentine SAC-A spacecrafts. The SAC-A pre-flight test data obtained by using the STR2760 simulator and the comparison with preliminary analysis of the GPS data from SAC-A telemetry are summarized. This paper describes pre-flight tests and simulations used to support a unique spaceborne GPS experiment. The GPS experiment mission objectives and the test program are described, as well as the GPS test facility configuration needed to verify experiment feasibility. Some operational and critical issues inherent in GPS receiver pre-flight tests and simulations using this GPS simulator, and test methodology are described. Simulation and flight data are presented. A complete program of pre-flight testing of spaceborne GPS receivers using a GPS constellation simulator is detailed.
Pre-Flight Testing of Spaceborne GPS Receivers using a GPS Constellation Simulator
NASA Technical Reports Server (NTRS)
Kizhner, Semion; Davis, Edward; Alonso, R.
The NASA Goddard Space Flight Center (GSFC) Global Positioning System (GPS) applications test facility has been established within the GSFC Guidance Navigation and Control Center. The GPS test facility is currently housing the Global Simulation Systems Inc. (GSSI) STR2760 GPS satellite 40-channel attitude simulator and a STR4760 12-channel navigation simulator. The facility also contains a few other resources such as an atomic time standard test bed, a rooftop antenna platform and a radome. It provides a new capability for high dynamics GPS simulations of space flight that is unique within the aerospace community. The GPS facility provides a critical element for the development and testing of GPS based technologies i.e. position, attitude and precise time determination used on-board a spacecraft, suborbital rocket balloon. The GPS simulation system is configured in a transportable rack and is available for GPS component development as well as for component, spacecraft subsystem and system level testing at spacecraft integration and tests sites. The GPS facility has been operational since early 1996 and has utilized by space flight projects carrying GPS experiments, such as the OrbView-2 and the Argentine SAC-A spacecrafts. The SAC-A pre-flight test data obtained by using the STR2760 simulator and the comparison with preliminary analysis of the GPS data from SAC-A telemetry are summarized. This paper describes pre-flight tests and simulations used to support a unique spaceborne GPS experiment. The GPS experiment mission objectives and the test program are described, as well as the GPS test facility configuration needed to verify experiment feasibility. Some operational and critical issues inherent in GPS receiver pre-flight tests and simulations using this GPS simulation, and test methodology are described. Simulation and flight data are presented. A complete program of pre-flight testing of spaceborne GPS receivers using a GPS constellation simulator is detailed.
Availability, reliability and accuracy of GPS signal in Bandar Baru Bangi for the determination of vehicle position and speed
Ishak Mohamad; M. Ali; M. Ismail
The Global Positioning System (GPS) provides special features which can be utilized for wide range of applications. By providing information such as location, direction and speed, GPS is traditionally used for navigation. Nowadays many more applications, from farming, surveying to incident detection in fact fully utilized the GPS. This study accesses GPS signal and determines vehicle location and speed parameter
GOES image navigation and registration system
NASA Astrophysics Data System (ADS)
Kamel, Ahmed
The GOES I-M image navigation and registration (INR) system was developed and patented by Space Systems/Loral in response to NASA/NOAA pointing requirements of Imager and Sounder payloads. This INR system is divided into space segment and ground segment. The space segment consist of image motion compensation (IMC) system that compensates for deterministic errors caused by orbit and attitude motions and mirror motion compensations system that compensates for spacecraft attitude motion caused by Imager and Sounder scanner mirror motion. The ground segment consists mainly of Orbit and Attitude Tracking System (OATS) that determines the IMC orbit and attitude coefficients from star, landmark, and range measurements.
Navigation of an intelligent vehicle by using stand-alone GPS, compass and laser range finder
C. Wuthishuwong; C. Silawatchananai; M. Parnichkun
Intelligent vehicle is the vehicle which has ability to drive itself autonomously and purposefully. The vehicle is expected to facilitate the people who cannot drive. Some modules of the vehicle; steering control, for instances, can assist the driver to make the driver drive more comfortable and safely. This paper proposes an autonomous navigation and control algorithm which is capable to
An Adaptive Fuzzy Strong Tracking Kalman Filter for GPS\\/INS Navigation
Dah-Jing Jwo; Cheng-Min Huang
The Kalman filtering is a form of recursive optimal estimation, which has been widely applied to the navigation designs. Kalman filter requires that all the plant dynamics and noise processes are exactly known, and the noise process is zero mean white noise. If the theoretical behavior of a filter and its actual behavior do not agree, divergence problems will occur.
[Transsphenoidal surgery assisted by navigation system].
Abe, M; Udono, H; Tabuchi, K; Uchino, A
Microneurosurgical technique combined with precise localization of lesions, can minimize the invasiveness of neurosurgical procedures. This report describes the usefulness of the neuronavigation system in transsphenoidal surgery. Nineteen transsphenoidal operations for sellar lesions including pituitary adenoma, clival chordoma, Rathke's cleft cyst and suprasellar germinoma were assisted by the optical tracking system (OTS). Operations were performed either through the sublabial or the endonasal approach using an operative microscope and, to a certain extent, the endoscope. All five microadenomas were totally removed. The tumors could be precisely localized by the navigation system. Four out of seven macroadenomas were totally removed. The operations were assisted effectively by the excellent guidance to the lateral margin of the tumors and the internal carotid arteries provided by the navigation system. The endonasal approach, in which the surgeon looks through a nostril at the sellar floor obliquely, was especially facilitated by the three-dimensional view provided by the system. The navigation system, however, was not useful in estimating the amount of the suprasellar residual tumor because of the dislocation that occurred during the tumor removal. PMID:11218764
System architecture study of an orbital GPS user terminal
NASA Technical Reports Server (NTRS)
Martin, D. P.; Neily, C. M., Jr.
The generic RF and applications processing requirements for a GPS orbital navigator are considered. A line of demarcation between dedicated analog hardware, and software/processor implementation, maximizing the latter is discussed. A modular approach to R/PA design which permits several varieties of receiver to be constructed from basic components is described. It is a basic conclusion that software signal processing of the output of the baseband correlator is the best choice of transition from analog to digital signal processing. High performance sets requiring multiple channels are developed from a generic design by replicating the RF processing segment, and modifying the applications software to provide enhanced state propagation and estimation.
Global Positioning System (GPS) Time Dissemination for Real-Time Applications
Peter H. Dana
This paper presents an overview of the Global Positioning System (GPS) for the potential precise time and time interval user with special reference to real-time systems. An overview of GPS operation is presented, and GPS error sources are described as they relate to the timing user. A review of receiver types and receiver tasks provides the basis for understanding GPS
Enhancing In-Car Navigation Systems with Personal Experience
Golbeck, Jennifer
1 Enhancing In-Car Navigation Systems with Personal Experience Benjamin B. Bederson Human present a framework for adding subjective human experience to in-car navigation systems. People often rely with traditional in-car navigation systems. INTRODUCTION Designers have just begun to realize the potential
Libration Point Navigation Concepts Supporting the Vision for Space Exploration
NASA Technical Reports Server (NTRS)
Carpenter, J. Russell; Folta, David C.; Moreau, Michael C.; Quinn, David A.
This work examines the autonomous navigation accuracy achievable for a lunar exploration trajectory from a translunar libration point lunar navigation relay satellite, augmented by signals from the Global Positioning System (GPS). We also provide a brief analysis comparing the libration point relay to lunar orbit relay architectures, and discuss some issues of GPS usage for cis-lunar trajectories.
The REFSAT approach to low-cost GPS terminals
NASA Technical Reports Server (NTRS)
Sennott, J. W.; Choudhury, A. K.; Taylor, R. E.
A concept utilizing a geostationary reference satellite (REFSAT) that broadcasts navigation aiding signals to low cost civil user terminals which employ the constellation of 24 NAVSTAR Global Positioning System (GPS) satellites for position determination is described. The signal acquisition, tracking and position fixing properties of such low cost, dual channel, L-band, civil user receiver designed to receive both GPS navigation and REFSAT navigation aiding signals is presented. REFSAT reduces the cost of user equipment.
Proceedings of GPS/GNSS 2003 Conference (Session C3), Portland, OR, September 9-12, 2003, The Institute of Navigation. 1/7 INDOOR POSITIONING SYSTEM USING ACCELEROMETRY
Calgary, University of
heading information. In this paper, the heading problem is resolved by using one deg/hour ring laser gyros solution accuracy degrades significantly. Size restrictions on current ring laser gyros limit positioning system is rather unrealistic due to the rapidly growing positioning errors caused by gyro drifts
A fuzzy logic map matching for wheelchair navigation
Ming RenHassan; Hassan A. Karimi
Global Positioning System (GPS) plays a central role in solving the location-based needs of wheelchair users and efficient\\u000a route guidance. An essential process in wheelchair navigation is matching the position obtained from GPS or other sensors\\u000a on a sidewalk network. This process of map matching in turn assists in making decisions under uncertainty. However, GPS-based\\u000a wheelchair navigation systems have difficulties
The Doppler inertial acoustic system for littoral navigation (DIAS)
G. M. Trimble
The Doppler inertial acoustic system (DIAS) is a compact, low-power, inertially-aided Doppler velocity navigation system which was developed to enhance the navigation capabilities of an unmanned underwater vehicle (UUV) in search, reacquisition, and inspection applications. Based on experience gained in the employment of long-baseline acoustic navigation approach using the divers acoustic navigation system (DANS) in support of the explosive ordnance
NSDL National Science Digital Library
In this unit, students learn the very basics of navigation, including the different kinds of navigation and their purposes. The concepts of relative and absolute location, latitude, longitude and cardinal directions are explored, as well as the use and principles of maps and a compass. Students discover the history of navigation and learn the importance of math and how it ties into navigational techniques. Understanding how trilateration can determine one's location leads to a lesson on the global positioning system and how to use a GPS receiver. The unit concludes with an overview of orbits and spacecraft trajectories from Earth to other planets.
Simulation of Guidance, Navigation, and Control Systems for Formation Flying Missions
NASA Technical Reports Server (NTRS)
Burns, Rich; Bauer, Frank H. (Technical Monitor)
Concepts for missions of distributed spacecraft flying in formation abound. From high resolution interferometry to spatially distributed in-situ measurements, these mission concepts levy a myriad of guidance, navigation, and control (GNC) requirements on the spacecraft/formation as a single system. A critical step toward assessing and meeting these challenges lies in realistically simulating distributed spacecraft systems. The Formation Flying TestBed (FFTB) at NASA Goddard Space Flight Center's (GSFC) Guidance, Navigation, and Control Center is a hardware-in-the-loop simulation and development facility focused on GNC issues relevant to formation flying systems. The FFTB provides a realistic simulation of the vehicle dynamics and control for formation flying missions in order to: (1) conduct feasibility analyses of mission requirements, (2) conduct and answer mission and spacecraft design trades, and (3) serve as a host for GNC software and hardware development and testing. The initial capabilities of the FFTB are based upon an integration of high fidelity hardware and software simulation, emulation, and test platforms developed or employed at GSFC in recent years, including a high-fidelity Global Positioning System (GPS) simulator which has been a fundamental component of the GNC Center's GPS Test Facility. The FFTB will be continuously evolving over the next several years from a tool with capabilities in GPS navigation hardware/software-in-the-loop analysis and closed loop GPS-based orbit control algorithm assessment. Eventually, it will include full capability to support all aspects of multi-sensor, absolute and relative state determination and control, in all (attitude and orbit) degrees of freedom, as well as information management for satellite clusters and constellations. A detailed description of the FFTB architecture is presented in the paper.
Enhancing In-Car Navigation Systems with Personal Experience
Golbeck, Jennifer
Enhancing In-Car Navigation Systems with Personal Experience Benjamin B. Bederson Human at these kinds of problems. We present a framework for adding subjective human experience to in-car navigation be used in conjunction with traditional in-car navigation systems. INTRODUCTION Designers have just begun
An Heuristic Method for GPS Surveying Stefka Fidanova
Fidanova, Stefka
, to analyze and improve the efficiency of the design of Global Positioning System (GPS) surveying networks of computational effort. The Global Positioning System is a satellite-based radio-navigation system that permits. The most widely known space systems are: the American Global Positioning System (GPS), the Russian GLObal
Determination of global positioning system (GPS) receiver clock errors: impact on positioning accuracy
Ta-Kang Yeh; Cheinway Hwang; Guochang Xu; Chuan-Sheng Wang; Chien-Chih Lee
Enhancing the positioning precision is the primary pursuit of global positioning system (GPS) users. To achieve this goal, most studies have focused on the relationship between GPS receiver clock errors and GPS positioning precision. This study utilizes undifferentiated phase data to calculate GPS clock errors and to compare with the frequency of cesium clock directly, to verify estimated clock errors
Noise analysis for X-ray navigation systems
John Hanson; Suneel Sheikh; Paul Graven; John Collins
Much as the Global Positioning System has ushered in an era of autonomous navigation on a global scale, X-ray navigation (XNAV) offers the possibility of autonomous navigation anywhere in the solar system. X-ray astronomers have identified a number of X-ray pulsars whose pulsed emissions have stabilities comparable to atomic clocks. X-ray navigation uses phase measurements from these sources to establish
GPS Problem Math21a, 2003-2008 The global positioning system GPS uses the fact that a receiver can get the differ-
Knill, Oliver
GPS Problem Math21a, 2003-2008 The global positioning system GPS uses the fact that a receiver can get the differ- ence of distances to two satellites. Each GPS satellite sends periodically signals is in general the set of points for which these distances match? Conclude that we can determine the GPS receiver
Obstacle-avoiding navigation system
Borenstein, Johann (Ann Arbor, MI); Koren, Yoram (Ann Arbor, MI); Levine, Simon P. (Ann Arbor, MI)
A system for guiding an autonomous or semi-autonomous vehicle through a field of operation having obstacles thereon to be avoided employs a memory for containing data which defines an array of grid cells which correspond to respective subfields in the field of operation of the vehicle. Each grid cell in the memory contains a value which is indicative of the likelihood, or probability, that an obstacle is present in the respectively associated subfield. The values in the grid cells are incremented individually in response to each scan of the subfields, and precomputation and use of a look-up table avoids complex trigonometric functions. A further array of grid cells is fixed with respect to the vehicle form a conceptual active window which overlies the incremented grid cells. Thus, when the cells in the active window overly grid cell having values which are indicative of the presence of obstacles, the value therein is used as a multiplier of the precomputed vectorial values. The resulting plurality of vectorial values are summed vectorially in one embodiment of the invention to produce a virtual composite repulsive vector which is then summed vectorially with a target-directed vector for producing a resultant vector for guiding the vehicle. In an alternative embodiment, a plurality of vectors surrounding the vehicle are computed, each having a value corresponding to obstacle density. In such an embodiment, target location information is used to select between alternative directions of travel having low associated obstacle densities.
Fiber optic gyroscopes for vehicle navigation systems
NASA Astrophysics Data System (ADS)
Kumagai, Tatsuya; Soekawa, Hirokazu; Yuhara, Toshiya; Kajioka, Hiroshi; Oho, Shigeru; Sonobe, Hisao
Fiber optic gyroscopes (FOGs) have been developed for vehicle navigation systems and are used in Toyota Motor Corporation models Mark II, Chaser and Cresta in Japan. Use of FOGs in these systems requires high reliability under a wide range of conditions, especially in a temperature range between -40 and 85 degree(s)C. In addition, a high cost-performance ratio is needed. We have developed optical and electrical systems that are inexpensive and can perform well. They are ready to be mass-produced. FOGs have already been installed in luxury automobiles, and will soon be included in more basic vehicles. We have developed more inexpensive FOGs for this purpose.
Inertial navigation system for directional surveying
Kohler, S.M.
A Wellbore Inertial Navigation System (WINS) was developed and tested. Developed for directional surveying of geothermal, oil, and gas wells, the system uses gyros and accelerometers to obtain survey errors of less than 10 ft (approx. 3 m) in a 10,000-ft (approx. 300-m) well. The tool, which communicates with a computer at the surface, is 4 in. (approx. 10 cm) in diameter and 20 ft (approx. 6.1 m) long. The concept and hardware is based on a system developed by Sandia for flight vehicles.
Tightly Coupled Integration of Ionosphere-Constrained Precise Point Positioning and Inertial Navigation Systems
Gao, Zhouzheng; Zhang, Hongping; Ge, Maorong; Niu, Xiaoji; Shen, Wenbin; Wickert, Jens; Schuh, Harald
The continuity and reliability of precise GNSS positioning can be seriously limited by severe user observation environments. The Inertial Navigation System (INS) can overcome such drawbacks, but its performance is clearly restricted by INS sensor errors over time. Accordingly, the tightly coupled integration of GPS and INS can overcome the disadvantages of each individual system and together form a new navigation system with a higher accuracy, reliability and availability. Recently, ionosphere-constrained (IC) precise point positioning (PPP) utilizing raw GPS observations was proven able to improve both the convergence and positioning accuracy of the conventional PPP using ionosphere-free combined observations (LC-PPP). In this paper, a new mode of tightly coupled integration, in which the IC-PPP instead of LC-PPP is employed, is implemented to further improve the performance of the coupled system. We present the detailed mathematical model and the related algorithm of the new integration of IC-PPP and INS. To evaluate the performance of the new tightly coupled integration, data of both airborne and vehicle experiments with a geodetic GPS receiver and tactical grade inertial measurement unit are processed and the results are analyzed. The statistics show that the new approach can further improve the positioning accuracy compared with both IC-PPP and the tightly coupled integration of the conventional PPP and INS. PMID:25763647
Fiber optic gyroscopes and the accomplishments of the DARPA-sponsored GPS guidance package program
Vicki C. LeFevre; William R. Lindberg
The Global Positioning System (GPS) Guidance Package (GGP) Program developed an affordable, navigation-grade, miniature guidance package based on a tightly coupled, integrated combination of a Miniature GPS Receiver (MGR) and miniature Inertial Navigation System (INS) including associated processors and Adaptable Interface Unit (AIU) functions. The GGP INS used Interferometric Fiber Optic Gyroscopes (IFOGs) and micro-machined silicon accelerometers. Several key challenges
Field Results of a GPS/INS-Based Approach to Measuring Ship Flexure Onboard an Aircraft
Calgary, University of
Field Results of a GPS/INS-Based Approach to Measuring Ship Flexure Onboard an Aircraft Carrier M navigation since 1998. He major research interests have been in GNSS system simulation and assessment, space extensively on the integration of GPS and inertial navigation systems for precise aircraft positioning. Dr
GPS water level measurements for Indonesia's Tsunami Early Warning System
NASA Astrophysics Data System (ADS)
Sch�ne, T.; Pandoe, W.; Mudita, I.; Roemer, S.; Illigner, J.; Zech, C.; Galas, R.
On Boxing Day 2004, a severe tsunami was generated by a strong earthquake in Northern Sumatra causing a large number of casualties. At this time, neither an offshore buoy network was in place to measure tsunami waves, nor a system to disseminate tsunami warnings to local governmental entities. Since then, buoys have been developed by Indonesia and Germany, complemented by NOAA's Deep-ocean Assessment and Reporting of Tsunamis (DART) buoys, and have been moored offshore Sumatra and Java. The suite of sensors for offshore tsunami detection in Indonesia has been advanced by adding GPS technology for water level measurements. The usage of GPS buoys in tsunami warning systems is a relatively new approach. The concept of the German Indonesian Tsunami Early Warning System (GITEWS) (Rudloff et al., 2009) combines GPS technology and ocean bottom pressure (OBP) measurements. Especially for near-field installations where the seismic noise may deteriorate the OBP data, GPS-derived sea level heights provide additional information. The GPS buoy technology is precise enough to detect medium to large tsunamis of amplitudes larger than 10 cm. The analysis presented here suggests that for about 68% of the time, tsunamis larger than 5 cm may be detectable.
Investigation of GPS/IMU Positioning System for Mining Equipment
Ken L. Stratton
The objective of this project is to investigate the applicability of a combined Global Positioning System and Inertial Measurement Unit (GPS/IMU) for information based displays on earthmoving machines and for automated earthmoving machines in the future. This technology has the potential of allowing an information-based product like Caterpillar's Computer Aided Earthmoving System (CAES) to operate in areas with satellite shading. Satellite shading is an issue in open pit mining because machines are routinely required to operate close to high walls, which reduces significantly the amount of the visible sky to the GPS antenna mounted on the machine. An inertial measurement unit is a product, which provides data for the calculation of position based on sensing accelerations and rotation rates of the machine's rigid body. When this information is coupled with GPS it results in a positioning system that can maintain positioning capability during time periods of shading.
33 CFR 164.72 - Navigational-safety equipment, charts or maps, and publications required on towing vessels.
Code of Federal Regulations, 2014 CFR
...position-fixing device. An electronic position-fixing device, a satellite navigational system such as the Global Positioning System (GPS) as required by � 164.41, if the vessel engages in towing seaward of navigable waters of the...
A method for increasing GPS working area
H. M. S. Abdel-Wahab; A. M. Hamad; S. Y. El-Aesa
The need for precise position and navigation aids in many areas of industry is becoming increasingly apparent. The driving force for this is our ability to determine the location of objects or features of the physical environment for use in map or chart making, and database development. The GPS represents one of the main systems for navigation aids. However, there
A complete navigation system for goal acquisition in unknown environments
Anthony Stentz; Martial Hebert
Most autonomous outdoor navigation systems tested on actual robots have centered on local navigation tasks such as avoiding obstacles or following roads. Global navigation has been limited to simple wandering, path tracking, straight-line goal seeking behaviors, or executing a sequence of scripted local behaviors. These capabilities are insufficient for unstructured and unknown environments, where replanning may be needed to account
A Complete Navigation System for Goal Acquisition in Unknown Environments
Anthony Stentz; Martial Hebert
Most autonomous outdoor navigation systems tested on actual robots have centered on local navigation tasks such as avoiding obstacles or following roads. Global navigation has been limited to simple wandering, path tracking, straight-line goal seeking behaviors, or executing a sequence of scripted local behaviors. These capabilities are insufficient for unstructured and unknown environments, where replanning may be needed to account
Robotics and Autonomous Systems 30 (2000) 133153 Biomimetic robot navigation
Robotics and Autonomous Systems 30 (2000) 133�153 Biomimetic robot navigation Matthias O. Franz Abstract In the past decade, a large number of robots has been built that explicitly implement biological applications, most notably in the field of indoor robot navigation. While simpler insect navigation behaviours
Accuracy assessment and improvement for level survey using real time kinematic (RTK) GPS
Dinesh Manandhar; Kiyoshi Honda; Shunji Murai
The Global Positioning System (GPS) is a satellite based positioning and navigation system that provides precise position, velocity and time information. The height accuracy in GPS is lower than the planimetric accuracy. This paper discusses about the height accuracy achievable in real time kinematic mode using single frequency GPS with Novatel's RT20 algorithm. Analysis was also done to see whether
Precise GPS orbits for geodesy
NASA Technical Reports Server (NTRS)
Colombo, Oscar L.
The Global Positioning System (GPS) has become, in recent years, the main space-based system for surveying and navigation in many military, commercial, cadastral, mapping, and scientific applications. Better receivers, interferometric techniques (DGPS), and advances in post-processing methods have made possible to position fixed or moving receivers with sub-decimeter accuracies in a global reference frame. Improved methods for obtaining the orbits of the GPS satellites have played a major role in these achievements; this paper gives a personal view of the main developments in GPS orbit determination.
International GPS (Global Positioning System) Service for Geodynamics
NASA Technical Reports Server (NTRS)
Zumberge, J. F. (Editor); Liu, R. (Editor); Neilan, R. E. (Editor)
The International GPS (Global Positioning System) Service for Geodynamics (IGS) began formal operation on January 1, 1994. This first annual report is divided into sections, which mirror different aspects of the service. Section (1) contains general information, including the history of the IGS, its organization, and the global network of GPS tracking sites; (2) contains information on the Central Bureau Information System; (3) describes the International Earth Rotation Service (IERS); (4) details collecting and distributing IGS data in Data Center reports; (6) describes how the IGS Analysis Centers generate their products; (7) contains miscellaneous contributions from other organizations that share common interests with the IGS.
An advanced, low cost, GPS-based animal tracking system
Technology Transfer Automated Retrieval System (TEKTRAN)
An improved GPS-based animal tracking system is needed to meet quickly-evolving ecological research and natural resource management demands. Commercially-available tracking systems lack the data storage capacity needed to frequently collect animal location data (e.g., at less than 5-minute interval...
Pre-Flight Testing of Spaceborne GPS Receivers Using a GPS Constellation Simulator
NASA Technical Reports Server (NTRS)
Kizhner, Semion; Alonso, Roberto
The NASA Goddard Space Flight Center (GSFC) Global Positioning System (GPS) test facility has been established within the GSFC Guidance Navigation and Control Center. The GPS test facility is currently housing the STR2760 GPS satellite 40-channel attitude simulator and an STR4760 12-channel navigation simulator. The facility also contains a few other Goddard resources such as an atomic time standard test bed, a rooftop antenna platform and a radome. It provides a new capability of high dynamics GPS simulations for space flight that is unique within the aerospace community. The GPS facility gives a significant advantage in the development and support of GPS based technologies for position, attitude and precise time determination on-board a spacecraft, sounding rocket or balloon. The GPS simulator system is configured in a transportable rack and is available for GPS applications' component development as well as for spacecraft subsystem and system level testing at spacecraft integration and test sites. The GPS facility has been operational since early 1996 and has been already utilized by a few successful flight projects carrying GPS experiments, such as USA Seastar satellite and the first Argentine satellite SAC-A. The experience in the SAC-A pre-flight testing using the STR2760 simulator is summarized as well as the comparison with preliminary analysis of the GPS data from SAC-A telemetry.
Preliminary navigation accuracy analysis for the TDRSS Onboard Navigation System (TONS) experiment on EP/EUVE
NASA Technical Reports Server (NTRS)
Gramling, C. J.; Long, A. C.; Lee, T.; Ottenstein, N. A.; Samii, M. V.
A Tracking and Data Relay Satellite System (TDRSS) Onboard Navigation System (TONS) is currently being developed by NASA to provide a high accuracy autonomous navigation capability for users of TDRSS and its successor, the Advanced TDRSS (ATDRSS). The fully autonomous user onboard navigation system will support orbit determination, time determination, and frequency determination, based on observation of a continuously available, unscheduled navigation beacon signal. A TONS experiment will be performed in conjunction with the Explorer Platform (EP) Extreme Ultraviolet Explorer (EUVE) mission to flight quality TONS Block 1. An overview is presented of TONS and a preliminary analysis of the navigation accuracy anticipated for the TONS experiment. Descriptions of the TONS experiment and the associated navigation objectives, as well as a description of the onboard navigation algorithms, are provided. The accuracy of the selected algorithms is evaluated based on the processing of realistic simulated TDRSS one way forward link Doppler measurements. The analysis process is discussed and the associated navigation accuracy results are presented.
Satellite emission radio interferometric earth surveying series - GPS geodetic system
NASA Technical Reports Server (NTRS)
Macdoran, P. F.
A concept called SERIES (satellite emissions radio interferometric earth surveying) which makes use of GPS (global positioning system) radio transmissions without any satellite modifications, is described. Through the use of very long baseline interferometry (VLBI) and its calibration methods, 0.5 to 3 cm three dimensional baseline accuracy can be achieved over distances of 2 to 200 km respectively, with only 2 hours of on-site data acquisition. Attention is given to such areas as: the radio flux equivalent of GPS transmissions, synthesized delay precision, transmission and frequency subsystem requirements, tropospheric and ionospheric errors. Applications covered include geodesy and seismic tectonics.
Results of demonstrating the GPS guidance package integrated in an army fire support team vehicle
Beth M. Kaspar; Mary C. Redshaw
This paper presents the results of a joint demonstration of an advanced navigation set conducted by the Advanced Research Projects Agency (ARPA) and the US Army Missile Command (MICOM). The Global Positioning System (GPS) guidance package (GGP) tightly couples a miniature GPS receiver (MGR) and a miniature inertial measurement unit (MIMU). The MIMU features a triad of navigation-grade interferometric fiber-optic
Stanford University
GPS/INS GENERALIZED EVALUATION TOOL (GIGET) FOR THE DESIGN AND TESTING OF INTEGRATED NAVIGATION Approved for the University Committee on Graduate Studies. #12;iv #12;v Abstract GIGET, the GPS/INS Generalized Evaluation Tool, experimentally tests, evaluates, and compares navigation systems that combine
Vibrotactile in-vehicle navigation system
Jan B. F. Van Erp
A vibrotactile display, consisting of eight vibrating elements or tactors mounted in a driver�s seat, was tested in a driving simulator. Participants drove with visual, tactile and multimodal navigation displays through a built-up area. Workload and the reaction time to navigation messages were measured for normal and high workload conditions. The results demonstrated that the tactile navigation display reduces the
Self-contained, high-altitude navigation system study: Prais navigation system
D. H. Aldrich; J. W. Simmons; N. F. Toda
Circuits to add a passive ranging capability to the Interferometric Landmark Tracker (ILT) to form a Passive Range Interferometer Sensor (PRAIS) were built and tested in the laboratory. The laboratory test data were used in a Monte Carlo simulation to demonstrate the performance of the PRAIS Navigation System in a highly eliptical orbit and a synchronous (1 deg inclination) orbit.
Presented at Institute of Navigation GPS2002 (September 24-27, 2002, Portland, OR) 1 Fault Detection Methods And Testing
Calgary, University of
Detection Methods And Testing For Marine GPS Receivers G. MacGougan and J. Liu Department of Geomatics. Investigative testing involved a selection of typical marine-grade GPS receivers. The receivers' susceptibility This research involves development of fault detection methods and testing of marine-grade GPS receivers
Compensating For GPS Ephemeris Error
NASA Technical Reports Server (NTRS)
Wu, Jiun-Tsong
Method of computing position of user station receiving signals from Global Positioning System (GPS) of navigational satellites compensates for most of GPS ephemeris error. Present method enables user station to reduce error in its computed position substantially. User station must have access to two or more reference stations at precisely known positions several hundred kilometers apart and must be in neighborhood of reference stations. Based on fact that when GPS data used to compute baseline between reference station and user station, vector error in computed baseline is proportional ephemeris error and length of baseline.
Global Positioning System (GPS) Bias Correction and Habitat Analysis of
Wallin, David O.
) Bias Correction and Habitat Analysis of Mountain Goats Oreamnos americanus in the Cascades Seasonal variation in habitat selection by the mountain goat Oreamnos americanus is not well understood dueGlobal Positioning System (GPS) Bias Correction and Habitat Analysis of Mountain Goats Oreamnos
Estimating Zenith Tropospheric Delays from BeiDou Navigation Satellite System Observations
Xu, Aigong; Xu, Zongqiu; Ge, Maorong; Xu, Xinchao; Zhu, Huizhong; Sui, Xin
The GNSS derived Zenith Tropospheric Delay (ZTD) plays today a very critical role in meteorological study and weather forecasts, as ZTDs of thousands of GNSS stations are operationally assimilated into numerical weather prediction models. Recently, the Chinese BeiDou Navigation Satellite System (BDS) was officially announced to provide operational services around China and its neighborhood and it was demonstrated to be very promising for precise navigation and positioning. In this contribution, we concentrate on estimating ZTD using BDS observations to assess its capacity for troposphere remote sensing. A local network which is about 250 km from Beijing and comprised of six stations equipped with GPS- and BDS-capable receivers is utilized. Data from 5 to 8 November 2012 collected on the network is processed in network mode using precise orbits and in Precise Point Positioning mode using precise orbits and clocks. The precise orbits and clocks are generated from a tracking network with most of the stations in China and several stations around the world. The derived ZTDs are compared with that estimated from GPS data using the final products of the International GNSS Service (IGS). The comparison shows that the bias and the standard deviation of the ZTD differences are about 2 mm and 5 mm, respectively, which are very close to the differences of GPS ZTD estimated using different software packages. PMID:23552104
Temporal and spatial precursors in the ionospheric global positioning system (GPS) total electron content observed
Chen, Yuh-Ing
Temporal and spatial precursors in the ionospheric global positioning system (GPS) total electron maps of the TEC derived from worldwide groundbased receivers of the global positioning system (GPS in the ionospheric global positioning system (GPS) total electron content observed before the 26 December 2004 M9
A scalable Web GPS monitoring system based on AJAX push pattern
Lei Shen; Chongjun Yang; Fuqing Zhang; Yingchao Ren; Lei Wu; Lin Zhu
With Ajax firmly established as a widespread Web application-development technique, it is possible to build GPS monitoring system based on B\\/S architecture, so a large number of Web GPS monitoring systems are released recently. This article analyzes the common GPS monitoring systems based on AJAX and points out three main existing weaknesses. Then the article introduces how to use AJAX
Precise navigation for the Earth Observing System (EOS)AM1 spacecraft using the TDRSS Onboard Navigation System (TONS)
David C. Folta; Bryant Elrod; Mark Lorenz; Ajay Kapoor
As the baseline navigation system for the Earth Observing System (EOS)-AM1 spacecraft, the Tracking and Data Relay Satellite System (TDRSS) Onboard Navigation System (TONS) is required to provide precise position and velocity information for imaging instrument calibration and routine operations. This paper presents the results of real-time navigation performance evaluations with respect to TONS-based orbit and frequency determination to satisfy
IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION, VOL. 19, NO. 1, FEBRUARY 2003 15 Autonomous Vehicle Positioning With GPS in
Ge, Shuzhi Sam
--The Global Positioning System (GPS) has been widely used in land vehicle navigation applications. However problems successfully. Index Terms--Extended Kalman filtering, Global Positioning System (GPS), interacting multiple model, joint parameter and state estimation. I. INTRODUCTION THE GLOBAL Positioning System (GPS
GPS vs Galileo: Balancing for Position in Space
Scott W. Beidleman
This study comprises an investigation of Europe's motives to develop the independent satellite navigation system known as Galileo, despite the existence of America's successful � and freely available � Global Positioning System (GPS). The study begins with an analysis of both systems to familiarize the reader with global navigation satellite systems (GNSS), to provide an understanding of the strengths and
NASA Astrophysics Data System (ADS)
Weiffenbach, George C.
The evolution, capabilities and uses of satellite-based navigation systems are explored, with emphasis on the accompanying space- and earth-based technologies. Early measurements of the Doppler shifts of Sputnik signals spurred development of the Transit satellite system as a precision navigation aid for Polaris submarines. The development of gravimetric programs to project the actual position of the satellites and the use of high frequency signals to offset ionospheric interference are noted. The design features, performances, and numerous launch and operational failures, of successive Transit spacecraft, i.e., the 5BN, 5C1 and Oscar satellites, are summarized. Details of the operational parameters and design features of the prototype and planned NAVSTAR GPS system are outlined, and plans for a SARSAT search and rescue satellite and the commercial GEOSTAR radionavigation and positioning system are described.
Tactile Wayfinder: Comparison of Tactile Waypoint Navigation with Commercial Pedestrian Navigation Systems
Martin Pielot; Susanne Boll
\\u000a In this paper we report on a field study comparing a commercial pedestrian navigation system to a tactile navigation system\\u000a called Tactile Wayfinder. Similar to previous approaches the Tactile Wayfinder uses a tactile torso display to present the directions of a route�s waypoints to the user. It advances those approaches by\\u000a conveying the location of the next two waypoints rather
Application of new GPS aircraft control/display system to topographic mapping of the Greenland ice cap
Wright, C.W. [Goddard Space Flight Center, Wallops Flight Center, Wallops Island, VA (United States); Swift, R.N. [Wallops Flight Facility, Wallops Island, VA (United States)
NASA has completed an accurate baseline map of the elevation of the Greenland ice sheet using a scanning airborne lidar in combination with differential kinematic Global Positioning System (GPS) techniques. The present plan is to reoccupy these survey lines which are spread over the major regions of the ice sheet beginning in 1997. The results are expected to provide a quantitative answer on how the ice sheet is responding to regional climatic changes. Navigation to within +-100 m of the desired track over lengths of up to 1,000 km are a requirement for the success of the program. To meet this navigational requirement, NASA developed the GPS Flight Management System (GFMS). GFMS is a PC based system that uses the real-time position update from a single GPS receiver located on the aircraft to calculate a cross-track error and generates aircraft steering commands which are converted into analog Instrument Landing System (OM) signals using an RF generator. TU GFMS also updates a cockpit display. 4 refs., 6 figs.
Observability analysis of a MEMS INS/GPS integration system with gyroscope G-sensitivity errors.
Fan, Chen; Hu, Xiaoping; He, Xiaofeng; Tang, Kanghua; Luo, Bing
Gyroscopes based on micro-electromechanical system (MEMS) technology suffer in high-dynamic applications due to obvious g-sensitivity errors. These errors can induce large biases in the gyroscope, which can directly affect the accuracy of attitude estimation in the integration of the inertial navigation system (INS) and the Global Positioning System (GPS). The observability determines the existence of solutions for compensating them. In this paper, we investigate the observability of the INS/GPS system with consideration of the g-sensitivity errors. In terms of two types of g-sensitivity coefficients matrix, we add them as estimated states to the Kalman filter and analyze the observability of three or nine elements of the coefficient matrix respectively. A global observable condition of the system is presented and validated. Experimental results indicate that all the estimated states, which include position, velocity, attitude, gyro and accelerometer bias, and g-sensitivity coefficients, could be made observable by maneuvering based on the conditions. Compared with the integration system without compensation for the g-sensitivity errors, the attitude accuracy is raised obviously. PMID:25171122
A visual navigation system for autonomous land vehicles
ALLEN M. WAXMAN; JACQUELINE J. LEMOIGNE; LARRY S. DAVIS; BABU SRINIVASAN; TODD R. KUSHNER; Eli Liang; THARAKESH SIDDALINGAIAH
A modular system architecture has been developed to support visual navigation by an autonomous land vehicle. The system consists of vision modules performing image processing, three-dimensional shape recovery, and geometric reasoning, as well as modules for planning, navigating, and piloting. The system runs in two distinct modes, bootstrap and feedforward. The bootstrap mode requires analysis of entire images to find
Intelligent Robotic Car for Autonomous Navigation: Platform and System Architecture
Leandro C. Fernandes; Jefferson R. Souza; Patrick. Y. Shinzato; Gustavo Pessin; Caio C. T. Mendes; Fernando S. Osorio; Denis F. Wolf
This paper presents the platform and system architecture of an intelligent vehicle, presenting the control system modules allowing the vehicle to navigate autonomously. Our research group has been developed works on autonomous navigation and driver assistance systems, using CaRINA I platform to experiments and validation. Our platform includes mechanical vehicle adaptations and the development of an embedded software architecture, and
Global Positioning System (GPS) Time Dissemination for Real-Time Applications
Peter H. Dana
This paper presents an overview of the Global Positioning System (GPS) for the potential precise time and time interval user with special reference to real -time systems. An overview of GPS operation is presented and GPS error sources are described as they relate to the timing user. A review of receiver types and receiver tasks provides the basis for understanding
GPS Time Synchronization System for K2K 1 H. G. Berns and R. J. Wilkes
Berns, Hans-Gerd
GPS Time Synchronization System for K2K 1 H. G. Berns and R. J. Wilkes Department of Physics System (GPS) provides a means for satisfying this requirement at very low cost. In addition to lowresolution time data (day of year, hour, minute, second), commercial GPS receivers output a 1 pulse per sec (1PPS
GPS Time Synchronization System for K2K1 H. G. Berns and R. J. Wilkes
Berns, Hans-Gerd
GPS Time Synchronization System for K2K1 H. G. Berns and R. J. Wilkes Department of Physics System (GPS) provides a means for satisfying this requirement at very low cost. In addition to low- resolution time data (day of year, hour, minute, second), commercial GPS receivers output a 1 pulse per sec
The real-time detection technology of city traffic condition based-on GPS system
Li Xiaojing; Meng Qingchun; Xiong Jianshe; Wei Tianbin; Wang Xuzhu; Ding Peng
The Global Positioning System (GPS) is the most popular satellite positioning system in the world at present. From the development of GPS and current traffic condition monitoring methods, the paper presents a new detection method of traffic condition based on the GPS technology. It can derive conveniently the driving time, demand velocity of vehicles and driveway occupancy, and obtain the
A navigation and control system for an autonomous rescue vehicle in the space station environment
NASA Technical Reports Server (NTRS)
Merkel, Lawrence
A navigation and control system was designed and implemented for an orbital autonomous rescue vehicle envisioned to retrieve astronauts or equipment in the case that they become disengaged from the space station. The rescue vehicle, termed the Extra-Vehicular Activity Retriever (EVAR), has an on-board inertial measurement unit ahd GPS receivers for self state estimation, a laser range imager (LRI) and cameras for object state estimation, and a data link for reception of space station state information. The states of the retriever and objects (obstacles and the target object) are estimated by inertial state propagation which is corrected via measurements from the GPS, the LRI system, or the camera system. Kalman filters are utilized to perform sensor fusion and estimate the state propagation errors. Control actuation is performed by a Manned Maneuvering Unit (MMU). Phase plane control techniques are used to control the rotational and translational state of the retriever. The translational controller provides station-keeping or motion along either Clohessy-Wiltshire trajectories or straight line trajectories in the LVLH frame of any sufficiently observed object or of the space station. The software was used to successfully control a prototype EVAR on an air bearing floor facility, and a simulated EVAR operating in a simulated orbital environment. The design of the navigation system and the control system are presented. Also discussed are the hardware systems and the overall software architecture.
Ubiquitous Positioning Technologies for Modern Intelligent Navigation Systems
NASA Astrophysics Data System (ADS)
Retscher, Guenther; Kealy, Allison
Recently new location technologies have emerged that can be employed in modern advanced navigation systems. They can be employed to augment Global Navigation Satellite System (GNSS) positioning techniques and dead reckoning as they offer different levels of positioning accuracies and performance. An integration of other technologies is especially required in indoor and outdoor-to-indoor environments. The paper gives an overview of the newly developed ubiquitous positioning technologies and their integration in navigation systems. Furthermore two case studies are presented, i.e., the improvement of land vehicle safety using Augmented Reality (AR) technologies and pedestrian navigation services for the guidance of users to certain University offices. In the first case study the integration of map matching into a Kalman filter approach is performed (referred to as �Intelligent Vehicle Navigation�) and its principle is briefly described. This approach can also be adapted for the pedestrian navigation service described in the second case study.
Precise Orbit Determination of BeiDou Navigation Satellite System
NASA Astrophysics Data System (ADS)
He, Lina; Ge, Maorong; Wang, Jiexian; Wickert, Jens; Schuh, Harald
China has been developing its own independent satellite navigation system since decades. Now the COMPASS system, also known as BeiDou, is emerging and gaining more and more interest and attention in the worldwide GNSS communities. The current regional BeiDou system is ready for its operational service around the end of 2012 with a constellation including five Geostationary Earth Orbit satellites (GEO), five Inclined Geosynchronous Orbit satellites (IGSO) and four Medium Earth orbit (MEO) satellites in operation. Besides the open service with positioning accuracy of around 10m which is free to civilian users, both precise relative positioning, and precise point positioning are demonstrated as well. In order to enhance the BeiDou precise positioning service, Precise Orbit Determination (POD) which is essential of any satellite navigation system has been investigated and studied thoroughly. To further improving the orbits of different types of satellites, we study the impact of network coverage on POD data products by comparing results from tracking networks over the Chinese territory, Asian-Pacific, Asian and of global scale. Furthermore, we concentrate on the improvement of involving MEOs on the orbit quality of GEOs and IGSOs. POD with and without MEOs are undertaken and results are analyzed. Finally, integer ambiguity resolution which brings highly improvement on orbits and positions with GPS data is also carried out and its effect on POD data products is assessed and discussed in detail. Seven weeks of BeiDou data from a ground tracking network, deployed by Wuhan University is employed in this study. The test constellation includes four GEO, five IGSO and two MEO satellites in operation. The three-day solution approach is employed to enhance its strength due to the limited coverage of the tracking network and the small movement of most of the satellites. A number of tracking scenarios and processing schemas are identified and processed and overlapping orbit differences are utilized to qualify the estimated orbits and clocks. The results show that GEO orbits, especially the along-track component, can be significantly improved by extending the tracking network in China along longitude direction, whereas IGSOs gain more improvement if the tracking network extends in latitude. For the current tracking network, deploying tracking stations on the eastern side, for example in New Zealand and/or in Hawaii, will significantly reduce along-track biases of GEOs on the same side. The involvement of MEOs and ambiguity-fixing also make the orbits better but rather moderate. Key words: BeiDou, precise orbit determination (POD), tracking network, ambiguity-fixing
Geospatial Information System for tracking and navigation of mobile objects
A. U. Alahakone; Veera Ragavan
Geospatial Information System (GIS) is a tool for manipulating, integrating and displaying geographically referenced information. It is a powerful system with high accuracy that is being used as the main backbone for a variety of path planning and navigation technologies widely used in the industry today. Tracking, security management, fleet management and industrial robot navigation are some regular applications. This
Optoelectronic image processing system for satellite landmark navigation
Sergey V. Dyblenko; Klaus Janschek; Anton Kisselev; Albert H. Sultanov; Valerij Tchernykh
Information system determining the satellite navigation parameters on the base of landmark image processing is considered. The concept of the optoelectronic navigation is based on the onboard optical correlator application for real time matching of the Earth images and prerecorded images of landmarks with known coordinates. The system is suitable for the low-orbit Earth imaging missions with 3-axis attitude stabilization
Precision hybrid navigation system for varied marine applications
S. Beiter; R. Poquette; B. S. Filipo; W. Goetz
A need has long been established to provide low cost precise inertial and integrated navigation systems for seaborne applications. The adaptation of low cost, high volume electronics and inertial sensors from Kearfott missile and land products has enabled this need to become a reality. The development of a low power navigation system for guidance of Unmanned Underwater Vehicles used in
A microcomputer-based low-cost Omega navigation system
NASA Technical Reports Server (NTRS)
Lilley, R. W.; Salter, R. J., Jr.
The application of a low cost, commercially available microcomputer as the navigation processor for a simplified OMEGA navigation system is an area of current research. The interface of a low cost front end OMEGA sensor is described and an example of the phase processing software and navigation routines is given. Emphasis is placed on the description of results obtained with the software version of the OMEGA burst filter known as the memory aided phase locked loop.
VIGIL: a GPS-based target-tracking system
NASA Astrophysics Data System (ADS)
Liebe, Carl C.; Brown, Kenneth A.; Udomkesmalee, Suraphol; Padgett, Curtis W.; Brenner, Michael P.; Howard, Ayanna M.; Wysocky, Terry R.; Brown, David I.; Suddarth, Steven C.
The VIGILANTE project is a planned vision system capable of tracking and recognizing targets in real time, on a small airborne platform. The project consists of two parts: (1) the viewing imager/gimballed instrumentation laboratory (VIGIL), which is an IR and visible sensor platform with appropriate optics and (2) the analog neural 3D processing experiment (ANTE), a massive parallel, neural based, high- speed processor. The VIGIL platform is mounted on a helicopter equipped with Global Position System (GPS), Inertia Measurement Unit (IMU), gimbal, radio-link and anti- vibration platform. Also, a jet powered, radio controlled VIGILANTE Target Vehicle (VTV) has been manufactured and equipped with GPS. In the first stages of the project, the VIGIL system is used to acquire image sequences of the VTV for training and testing of the ANTE image recognition processor. Based on GPS and IMU input, the gimbal is pointed toward the VTV and acquires images. This paper describes the VIGIL system in detail. It discusses position-based pointing, tracking algorithms and the alignment procedure. Test imagery and an evaluation of the system will be presented.
NSDL National Science Digital Library
This site features Flash animations that illustrate how the Global Positioning System (GPS) works. The animations depict how GPS signals are derived, compare geostationary and polar orbits, and explain satellites, ground control, and user segments, which comprise the three main GPS components. These resources are suitable for use in lectures, labs, or other teaching activities.
Navigation Flight Test Results from the Low Power Transceiver Communications and Navigation Demonstration on Shuttle (CANDOS) Experiment
NASA Technical Reports Server (NTRS)
Haas, Lin; Massey, Christopher; Baraban, Dmitri
This paper presents the Global Positioning System (GPS) navigation results from the Communications and Navigation Demonstration on Shuttle (CANDOS) experiment flown on STS-107. This experiment was the initial flight of a Low Power Transceiver (LPT) that featured high capacity space- space and space-ground communications and GPS- based navigation capabilities. The LPT also hosted the GPS Enhanced Orbit Determination Experiment (GEODE) orbit determination software. All CANDOS test data were recovered during the mission using LPT communications links via the Tracking and Data Relay Satellite System (TDRSS). An overview of the LPT s navigation software and the GPS experiment timeline is presented, along with comparisons of test results to the NASA Johnson Space Center (JSC) real-time ground navigation vectors and Best Estimate of Trajectory (BET).
GPS as an orbit determination subsystems
NASA Astrophysics Data System (ADS)
Fennessey, Richard; Roberts, Pat; Knight, Robin; Vanvolkinburg, Bart
This paper evaluates the use of Global Positioning System (GPS) receivers as a primary source of tracking data for low-Earth orbit satellites. GPS data is an alternative to using range, azimuth, elevation, and range-rate (RAER) data from the Air Force Satellite Control Network antennas, the Space Ground Link System (SGLS). This evaluation is applicable to missions such as Skipper, a joint U.S. and Russian atmosphere research mission, that will rely on a GPS receiver as a primary tracking data source. The Detachment 2, Space and Missile Systems Center's Test Support Complex (TSC) conducted the evaluation based on receiver data from the Space Test Experiment Platform Mission O (STEP-O) and Advanced Photovoltaic and Electronics Experiments (APEX) satellites. The TSC performed orbit reconstruction and prediction on the STEP-0 and APEX vehicles using GPS receiver navigation solution data, SGLS RAER data, and SGLS anglesonly (azimuth and elevation) data. For the STEP-O case, the navigation solution based orbits proved to be more accurate than SGLS RAER based orbits. For the APEX case, navigation solution based orbits proved to be less accurate than SGLS RAER based orbits for orbit prediction, and results for orbit reconstruction were inconclusive due to the lack of a precise truth orbit. After evaluating several different GPS data processing methods, the TSC concluded that using GPS navigation solution data is a viable alternative to using SGLS RAER data.
A ring laser gyro strapdown inertial navigation system - Performance analysis and test results
D. J. Pasik; M. I. Gneses; G. R. Taylor
A ring laser gyro (RLG) inertial navigation system has been extensively tested. An unusual characteristic of the RLG - random walk in its angular output - is described and analyzed. Four classes of test data are presented: calibration\\/alignment, static navigation, dynamic free navigation, and dynamic filtered navigation. Free navigation performance is about five miles per hour; filtered navigation, using self-damping
GPS Meteorology: Remote Sensing of Atmospheric Water Vapor Using the Global Positioning System
Michael Bevis; Steven Businger; Thomas A. Herring; Christian Rocken; Richard A. Anthes; Randolph H. Ware
We present a new approach to remote sensing of water vapor based on the global positioning system (GPS). Geodesists and geophysicists have devised methods for estimating the extent to which signals propagating from GPS satellites to ground-based GPS receivers are delayed by atmospheric water vapor. This delay is parameterized in terms of a time-varying zenith wet delay (ZWD) which is
Xiaolin Meng; Gethin Wyn Roberts; Emily Cosser; Alan Henry Dodson
GPS is used for various structural deformation monitoring, both for long-term deformations as well as instantaneous deflections. Due to the inherent deficiency in the GPS satellite geometry, multipath, residual tropospheric delay and cycle slips, GPS alone cannot provide the required positioning precision all the time to meet the requirements for such a system to detect subtle deformations of structures. The
ECE 174 Computer Assignment #2 --Due Thursday 12/1/2011 GLOBAL POSITIONING SYSTEM (GPS) ALGORITHM
Wang, Deli
to a systematic error caused by an inaccurate receiver clock (to keep the cost of commercial GPS units low by an inaccurate clock in the GPS receiver. The number of range measurements taken to each satellite, mECE 174 Computer Assignment #2 -- Due Thursday 12/1/2011 GLOBAL POSITIONING SYSTEM (GPS) ALGORITHM
What is GPS? Global radionavigation system, to provide locations in rea
Fialko, Yuri
What is GPS? � Global radionavigation system, to provide locations in rea military, with few-meter accuracy. � Conceived in the 1970's, first satellites launched 19 ``operational'' in 1994. #12;What is GPS in the 1970's, first satellites launched 19 ``operational'' in 1994. � Meanwhile..... #12;What is GPS
Local-area radio navigation: a tool for GPS-denied geolocation
NASA Astrophysics Data System (ADS)
Taylor, David W. A.; Johnson, Peter N.; Faulkner, W. T.
Ranger is a local area radio frequency ranging system implemented in the 2.4 GHz Industrial, Scientific andMedical band. Roundtrip time-of-flight measurements are made in a two-stage process: a coarse measurement provides +/- 3.4 m accuracy, followed by a fine measurement correction that reduces error to below 20 cm. This innovative approach can be implemented in other parts of the radio frequency spectrum; the 2.4 GHz band was chosen both for regulatory acceptance and availability of commercial components. The Ranger system consists of fixed and mobile radios. Fixed location radios provide the reference from which distances are measured to the mobile radio. A single distance measurement requires approximately 50 ms, therefore with a network of four fixed radios, the position of the mobile can be updated five times per second. Additionally, the digital communications link that is used for distance measurement is also used for concurrent high-bandwidth data communication.
Local-area radio navigation: a tool for GPS-denied geolocation
David W. A. Taylor; Peter N. Johnson; W. T. Faulkner
Ranger is a local area radio frequency ranging system implemented in the 2.4 GHz Industrial, Scientific andMedical band. Roundtrip time-of-flight measurements are made in a two-stage process: a coarse measurement provides +\\/- 3.4 m accuracy, followed by a fine measurement correction that reduces error to below 20 cm. This innovative approach can be implemented in other parts of the radio
Field testing a global positioning system (GPS) collar on a Japanese monkey: reliability of automatic GPS positioning in a Japanese forest
David S. Sprague; Hajime Kabaya; Ko Hagihara
A global positioning system (GPS) collar recorded the locations of an adult female Japanese macaque over a 9-day period in a habitat with mixed suburban and rural land-uses in Chiba Prefecture, Japan. The GPS device acquired positions even in forested areas. The GPS data located the female mostly in forested areas, although the female had ranged through a habitat with
Worldwide differential GPS for Space Shuttle landing operations
Peter V. W. Loomis; Robert P. Denaro; Penny Saunders
Worldwide differential Global Positioning System (WWDGPS) is viewed as an effective method of offering continuous high-quality navigation worldwide. The concept utilizes a network with as few as 33 ground stations to observe most of the error sources of GPS and provide error corrections to users on a worldwide basis. The WWDGPS real-time GPS tracking concept promises a threefold or fourfold
An introduction to GPS and its geodetic applications
Vidal Ashkenazi
Although Block II satellites have yet to be launched, GPS has already made a very significant impact on navigation, geodesy, surveying and geophysics. This introduction to GPS is aimed at the non-specialist who wants to understand the basic principles of the system, the way measurements are made, the level of accuracies achieved and potential applications. The lecture uses frequent analogies
An introduction to GPS and its geodetic applications
Vidal Ashkenazi
Although Block II satellites have yet to be launched, GPS has already made a very significant impact on navigation, geodesy, surveying and geophysics. This introduction to GPS is aimed at the non-specialist who wants to understand the basic principles of the system, the way measurements are made, the level of accuracies achieved and potential applications. The lecture uses frequent analogies
Long baseline clock comparison with multichannel GPS time receivers
J. H. Hahn; L. S. Schmidt
The paper shows how spread-spectrum signals can be used to allow the worldwide timing community to compare atomic clocks on a very precise level. For this a new generation of multichannel GPS time receivers has been applied. At the present time the international timing community has access to multichannel time receivers using the commonly known satellite navigation systems GPS and
Where in the World?: GPS Projects for the Technology Class
ERIC Educational Resources Information Center
Guccione, Sam
Global positioning system (GPS) has many uses. They include navigation, location finding, vehicle tracking, surveying, autonomous control of highway construction equipment, scientific activities, asset location and entertainment. The GPS is a constellation of 24 satellites located in a 10,000-mile radius orbit in a way that allows for at least six�
Matching GPS Observations to Locations on a Digital Map
Joshua S. Greenfeld
GPS based navigation and route guidance systems are becoming increasingly popular among bus operators, fleet managers and travelers. To provide this functionality, one has to have a GPS receiver, a digital map of the traveled network and software that can associate (match) the user's position with a location on the digital map. Matching the user's location has to be done
Updating the ionospheric delay model using gps data
E. L. Afraimovich; V. V. Chernukhov; V. V. Dernyanov
Introduction. The satellite radio navigation system GPS (Global Positioning System) provides the user's accurate positioning in the horizontal plane using the CIA-code of standard accuracy of up to 100 m [HofmannWellenhof et al., 19921. In this case the main source of errors in determining the coordinates is the delay caused by the propagation of the radio signal from the navigation
Fuzzy adaptive Kalman filtering for INS\\/GPS data fusion
J. Z. Sasiadek; Q. Wang; M. B. Zeremba
Presents a method for sensor fusion based on adaptive fuzzy Kalman filtering. The method is applied in fusing position signals from Global Positioning Systems (GPS) and inertial navigation systems (INS) for autonomous mobile vehicles. The presented method has been validated in a 3-D environment and is of particular importance for guidance, navigation, and control of flying vehicles. The extended Kalman
Feasibility of narrow beam crosslinks for the GPS phase III system
NASA Astrophysics Data System (ADS)
Weber, J. G.; Chao, C. C.; Baker, J. M.
The utilization of a narrow-beam antenna system to achieve a continuous communication chain between GPS spacecraft that encompasses all of the orbital planes has been assessed. Two concepts were considered. The first concept, which proved to be the most effective assumed a single antenna capable of electronically steering narrow-beam waves while the antenna remains fixed relative to the spacecraft body. The antenna was placed along the body z-axis which always points towards the center of the earth. The second concept assumed a dual set of antennas (located within the body xy plane) which are mechanically slewed to achieve crosslink communication. On-board autonomous navigation capabilities based on the crosslink range and range rate data have also been examined.
S. V. M. K. Prasad; T. Ananda; G. Boopalan; V. Vaidehi; P. V. Ramakrishna; C. N. Krishnan
GPS (Global Positioning System) signal simulator is a versatile instrument used for testing and performance evaluation of GPS receiver during its design and manufacture. GPS Signal simulator outputs the L1 signal of GPS satellites as received by the GPS receiver at its antenna. The generation of GPS signal requires the transmission of L1 signal at a rate of 1.023 Mbits\\/sec
Performance Comparison of Landmark Recognition Systems for Navigating Mobile Robots
Duckett, Tom
by wheel slippage and the need for a priori knowledge of the robot's position. A solution to bothPerformance Comparison of Landmark Recognition Systems for Navigating Mobile Robots Tom email@example.com Abstract Self-localisation is an essential competence for mobile robot navigation. Due to the fundamental
Dependable Humanoid Navigation System Based on Bipedal Locomotion
Yeonsik Kang; Hyunsoo Kim; Soo-Hyun Ryu; Nakju Lett Doh; YongHwan Oh; Bum-jae You
In this paper, a dependable humanoid navigation system is proposed by considering many difficulties in humanoid navigation based on bipedal locomotion in an uncertain environ- ment. In particular, we propose a layered architecture to resolve complicated problems through a hierarchical manner. Within the proposed software architecture, a walking path planner, a walking footstep planner, and a walking pattern generator are
Regionalized Lunar South Pole Surface Navigation System Analysis
NASA Technical Reports Server (NTRS)
Welch, Bryan W.
Apollo missions utilized Earth-based assets for navigation because the landings took place at lunar locations in constant view from the Earth. The new exploration campaign to the lunar south pole region will have limited Earth visibility, but the extent to which a navigation system comprised solely of Earth-based tracking stations will provide adequate navigation solutions in this region is unknown. This report presents a dilution-of-precision (DoP)-based, stationary surface navigation analysis of the performance of multiple lunar satellite constellations, Earth-based deep space network assets, and combinations thereof. Results show that kinematic and integrated solutions cannot be provided by the Earth-based deep space network stations. Also, the stationary surface navigation system needs to be operated either as a two-way navigation system or as a one-way navigation system with local terrain information, while the position solution is integrated over a short duration of time with navigation signals being provided by a lunar satellite constellation.
An IR Navigation System for Pleural PDT
Zhu, Timothy C.; Liang, Xing; Kim, Michele M.; Finlay, Jarod C.; Dimofte, Andreea; Rodriguez, Carmen; Simone, Charles B.; Friedberg, Joseph S.; Cengel, Keith A.
Pleural photodynamic therapy (PDT) has been used as an adjuvant treatment with lung-sparing surgical treatment for malignant pleural mesothelioma (MPM). In the current pleural PDT protocol, a moving fiber-based point source is used to deliver the light. The light fluences at multiple locations are monitored by several isotropic detectors placed in the pleural cavity. To improve the delivery of light fluence uniformity, an infrared (IR) navigation system is used to track the motion of the light source in real-time at a rate of 20 � 60 Hz. A treatment planning system uses the laser source positions obtained from the IR camera to calculate light fluence distribution to monitor the light fluence uniformity on the surface of the pleural cavity. A novel reconstruction algorithm is used to determine the pleural cavity surface contour. A dual-correction method is used to match the calculated fluences at detector locations to the detector readings. Preliminary data from a phantom shows superior light uniformity using this method. Light fluence uniformity from patient treatments is also shown with and without the correction method. PMID:25995987
Results from a GPS Shuttle Training Aircraft flight test
NASA Technical Reports Server (NTRS)
Saunders, Penny E.; Montez, Moises N.; Robel, Michael C.; Feuerstein, David N.; Aerni, Mike E.; Sangchat, S.; Rater, Lon M.; Cryan, Scott P.; Salazar, Lydia R.; Leach, Mark P.
A series of Global Positioning System (GPS) flight tests were performed on a National Aeronautics and Space Administration's (NASA's) Shuttle Training Aircraft (STA). The objective of the tests was to evaluate the performance of GPS-based navigation during simulated Shuttle approach and landings for possible replacement of the current Shuttle landing navigation aid, the Microwave Scanning Beam Landing System (MSBLS). In particular, varying levels of sensor data integration would be evaluated to determine the minimum amount of integration required to meet the navigation accuracy requirements for a Shuttle landing. Four flight tests consisting of 8 to 9 simulation runs per flight test were performed at White Sands Space Harbor in April 1991. Three different GPS receivers were tested. The STA inertial navigation, tactical air navigation, and MSBLS sensor data were also recorded during each run. C-band radar aided laser trackers were utilized to provide the STA 'truth' trajectory.
A tactile communication system for navigation
Piateski, Erin M
A vibrotactile display for use in navigation has been designed and evaluated. The arm and the torso, which offer relatively large and flat surface areas, were chosen as locations for the displays. The ability of subjects ...
A persuasive GPS-controlled thermostat system
Gupta, Manu, S. M. Massachusetts Institute of Technology
Using 10 weeks of data from a couple living in an instrumented home, we report on the potential of context-aware power management for energy saving. We identify an opportunity to save on heating and cooling using a system ...
The Problem of Compatibility and Interoperability of Satellite Navigation Systems in Computation of User's Position
NASA Astrophysics Data System (ADS)
Januszewski, Jacek
Actually (June 2011) more than 60 operational GPS and GLONASS (Satellite Navigation Systems - SNS), EGNOS, MSAS and WAAS (Satellite Based Augmentation Systems - SBAS) satellites are in orbits transmitting a variety of signals on multiple frequencies. All these satellite signals and different services designed for the users must be compatible and open signals and services should also be interoperable to the maximum extent possible. Interoperability definition addresses signal, system time and geodetic reference frame considerations. The part of compatibility and interoperability of all these systems and additionally several systems under construction as Compass, Galileo, GAGAN, SDCM or QZSS in computation user's position is presented in this paper. Three parameters - signal in space, system time and coordinate reference frame were taken into account in particular.
A Frequency-Domain INS/GPS Dynamic Response Method for Bridging GPS Outages
NASA Astrophysics Data System (ADS)
El-Diasty, Mohammed; Pagiatakis, Spiros
We develop a new frequency-domain dynamic response method to model integrated Inertial Navigation System (INS) and Global Positioning System (GPS) architectures and provide an accurate impulse-response-based INS-only navigation solution when GPS signals are denied (GPS outages). The input to such a dynamic system is the INS-only solution and the output is the INS/GPS integration solution; both are used to derive the transfer function of the dynamic system using Least Squares Frequency Transform (LSFT). The discrete Inverse Least Squares Frequency Transform (ILSFT) of the transfer function is applied to estimate the impulse response of the INS/GPS system in the time domain. It is shown that the long-term motion dynamics of a DQI-100 IMU/Trimble BD950 integrated system are recovered by 72%, 42%, 75%, and 40% for north and east velocities, and north and east positions respectively, when compared with the INS-only solution (prediction mode of the INS/GPS filter). A comparison between our impulse response model and the current state-of-the-art time-domain feed-forward neural network shows that the proposed frequency-dependent INS/GPS response model is superior to the neural network model by about 26% for 2D velocities and positions during GPS outages.
The International GNSS Service in a changing landscape of Global Navigation Satellite Systems
NASA Astrophysics Data System (ADS)
Dow, John M.; Neilan, R. E.; Rizos, C.
The International GNSS Service (IGS) is an international activity involving more than 200 participating organisations in over 80 countries with a track record of one and a half decades of successful operations. The IGS is a service of the International Association of Geodesy (IAG). It primarily supports scientific research based on highly precise and accurate Earth observations using the technologies of Global Navigation Satellite Systems (GNSS), primarily the US Global Positioning System (GPS). The mission of the IGS is �to provide the highest-quality GNSS data and products in support of the terrestrial reference frame, Earth rotation, Earth observation and research, positioning, navigation and timing and other applications that benefit society�. The IGS will continue to support the IAG�s initiative to coordinate cross-technique global geodesy for the next decade, via the development of the Global Geodetic Observing System (GGOS), which focuses on the needs of global geodesy at the mm-level. IGS activities are fundamental to scientific disciplines related to climate, weather, sea level change, and space weather. The IGS also supports many other applications, including precise navigation, machine automation, and surveying and mapping. This article discusses the IGS Strategic Plan and future directions of the globally-coordinated ~400 station IGS network, tracking data and information products, and outlines the scope of a few of its numerous working groups and pilot projects as the world anticipates a truly multi-system GNSS in the coming decade.
Navigation for space shuttle approach and landing using an inertial navigation system augmented by data from a precision ranging system or a microwave scan beam landing guidance system
NASA Technical Reports Server (NTRS)
Mcgee, L. A.; Smith, G. L.; Hegarty, D. M.; Merrick, R. B.; Carson, T. M.; Schmidt, S. F.
A preliminary study has been made of the navigation performance which might be achieved for the high cross-range space shuttle orbiter during final approach and landing by using an optimally augmented inertial navigation system. Computed navigation accuracies are presented for an on-board inertial navigation system augmented (by means of an optimal filter algorithm) with data from two different ground navigation aids; a precision ranging system and a microwave scanning beam landing guidance system. These results show that augmentation with either type of ground navigation aid is capable of providing a navigation performance at touchdown which should be adequate for the space shuttle. In addition, adequate navigation performance for space shuttle landing is obtainable from the precision ranging system even with a complete dropout of precision range measurements as much as 100 seconds before touchdown.
Application of Global Navigation Satellite System and Hydroacoustic Techniques to Safety of Inland Water Navigation
NASA Astrophysics Data System (ADS)
Popielarczyk, Dariusz
The paper presents description of application of integrated, Global Navigation Satellite System (GNSS) and hydroacoustic technologies, for elaboration of actual bathymetric chart and creation of an Inland Interactive Underwater Objects Base (IIUOD). In the paper the description of some integrated bathymetric experiments conducted on Great Mazurian Lakes is presented. A small area of Lake Sniardwy, the largest lake in Poland, has been measured using modern technology with precise satellite positioning and hydrographic techniques. The idea and first results of the implemented base is analyzed and described. The database (IIUOD) is created for visualization of dangerous underwater objects and finally for safety of inland water navigation.
Discrete-time observers for inertial navigation systems
Zhao, Yong, 1980-
In this thesis, we derive an exact deterministic nonlinear observer to compute the continuous-time states of inertial navigation system based on partial discrete measurements, the so-called strapdown problem. Nonlinear ...
Designing An Interplanetary Autonomous Spacecraft Navigation System Using Visible Planets�
Karimi, Reza
A perfect duality exists between the problem of space-based orbit determination from line-of-sight measurements and the problem of designing an interplanetary autonomous navigation system. Mathematically, these two problems are equivalent. Any...
A precise GPS-based time and frequency system
NASA Astrophysics Data System (ADS)
McNabb, Jack; Fossler, Earl
An approach to implementing a compact, highly reliable and precise Master Time and Frequency subsystem usable in a variety of applications is described. These applications include, among others, Satellite Ground Terminals, Range Timing Stations, Communications Terminals, and Power Station Timing subsystems. All time and frequency output signals are locked to Universal Time via the GPS Satellite system. The system provides for continued output of precise signals in the event of GPS signal interruption from antenna or lead-in breakage or other causes. Cost/performance tradeoffs affecting system accuracy over the short, medium, and long term are discussed. A unique approach to redundant system design provides an architecture with the reliability advantage of triple-redundant majority voting and the cost advantages of dual-redundant elements. The system can be configured to output a variety of precise time and frequency signals and the design can be tailored to output as few, or as many, types and quantities of signals as are required by the application.
Leica System 1200: Towards Sensor Synchronization of GPS and TPS for Kinematic Applications
Leica System 1200: Towards Sensor Synchronization of GPS and TPS for Kinematic Applications Werner Stempfhuber and Thomas Wunderlich 1 Introduction Modern measurement systems such as the robot tacheometer (Terrestrial Positioning System, TPS) or the " Glo- bal Positioning System (GPS)" allow discrete and high
A simulation of GPS and differential GPS sensors
NASA Technical Reports Server (NTRS)
Rankin, James M.
The Global Positioning System (GPS) is a revolutionary advance in navigation. Users can determine latitude, longitude, and altitude by receiving range information from at least four satellites. The statistical accuracy of the user's position is directly proportional to the statistical accuracy of the range measurement. Range errors are caused by clock errors, ephemeris errors, atmospheric delays, multipath errors, and receiver noise. Selective Availability, which the military uses to intentionally degrade accuracy for non-authorized users, is a major error source. The proportionality constant relating position errors to range errors is the Dilution of Precision (DOP) which is a function of the satellite geometry. Receivers separated by relatively short distances have the same satellite and atmospheric errors. Differential GPS (DGPS) removes these errors by transmitting pseudorange corrections from a fixed receiver to a mobile receiver. The corrected pseudorange at the moving receiver is now corrupted only by errors from the receiver clock, multipath, and measurement noise. This paper describes a software package that models position errors for various GPS and DGPS systems. The error model is used in the Real-Time Simulator and Cockpit Technology workstation simulations at NASA-LaRC. The GPS/DGPS sensor can simulate enroute navigation, instrument approaches, or on-airport navigation.
Precise orbit determination for NASA's Earth Observing System using GPS
NASA Technical Reports Server (NTRS)
Williams, Bobby G.
A precision orbit determination technique for NASA's Earth Observing System (EOS) is discussed. The technique exploits the redundant geometric information from GPS carrier phase and P-code pseudorange measurements and minimizes the requirements for precision dynamical modeling. Performance estimates for the application of the technique to the orbit geometry planned for the EOS platforms show that decimeter accuracies of orbit position may be obtained. The sensitivity of the predicted orbit uncertainties to model errors for station locations, nongravitational platform accelerations, and earth gravity are presented.
Principles and Applications of Polarized-light-aided Attitude Determination in Integrated Navigation
Hongqian Lu; Xianlin Huang; Hang Yin
To improve the attitude error correcting capabilities of GPS\\/SINS integrated navigation systems, a new method of polarized-light-based GPS\\/SINS integrated navigation is presented. The principles of polarized-light-aided attitude determination are demonstrated, and a multi-module approach is proposed to increases the degree of observability. The integrated navigation algorithm is implemented in frame of federated Kalman filtering. To verify the effects of the
A Real Time Differential GPS Tracking System for NASA Sounding Rockets
NASA Technical Reports Server (NTRS)
Bull, Barton; Bauer, Frank (Technical Monitor)
Sounding rockets are suborbital launch vehicles capable of carrying scientific payloads to several hundred miles in altitude. These missions return a variety of scientific data including: chemical makeup and physical processes taking place in the atmosphere, natural radiation surrounding the Earth, data on the Sun, stars, galaxies and many other phenomena. In addition, sounding rockets provide a reasonably economical means of conducting engineering tests for instruments and devices to be used on satellites and other spacecraft prior to their use in these more expensive missions. Typically around thirty of these rockets are launched each year, from established ranges at Wallops Island, Virginia; Poker Flat Research Range, Alaska; White Sands Missile Range, New Mexico and from a number of ranges outside the United States. Many times launches are conducted from temporary launch ranges in remote parts of the world requiring considerable expense to transport and operate tracking radars. In order to support these missions, an inverse differential GPS system has been developed. The flight system consists of a small, inexpensive receiver, a preamplifier and a wrap-around antenna. A rugged, compact, portable ground station extracts GPS data from the raw payload telemetry stream, performs a real time differential solution and graphically displays the rocket's path relative to a predicted trajectory plot. In addition to generating a real time navigation solution, the system has been used for payload recovery, timing, data timetagging, precise tracking of multiple payloads and slaving of optical tracking systems for over the horizon acquisition. This paper discusses, in detail, the flight and ground hardware, as well as data processing and operational aspects of the system, and provides evidence of the system accuracy.
NSDL National Science Digital Library
Garmin Ltd.
This site from Garmin describes GPS systems and the way that they work. Topics include the accuracy of GPS, the 24 satellites that make up the GPS space segment, the two low power radio signals that GPS satellites transmit, and the sources of GPS signal errors.
Positional accuracy of the Wide Area Augmentation System in consumer-grade GPS units
Lisa L. Arnold; Paul A. Zandbergen
Global Positioning System devices are increasingly being used for data collection in many fields. Consumer-grade GPS units without differential correction have a published horizontal positional accuracy of approximately 10�15m (average positional accuracy). An attractive option for differential correction for these GPS units is the Wide Area Augmentation System (WAAS). Most consumer-grade GPS units on the market are WAAS capable. According
Selected bibliography of OMEGA, VLF and LF techniques applied to aircraft navigation systems
NASA Technical Reports Server (NTRS)
A bibliography is presented which includes references to the OMEGA navigation system, very low frequencies, time-frequency measurements, air traffic control, radio navigation, and applications of OMEGA.
An indoor navigation system to support the visually impaired.
Riehle, T H; Lichter, P; Giudice, N A
Indoor navigation technology is needed to support seamless mobility for the visually impaired. A small portable personal navigation device that provides current position, useful contextual wayfinding information about the indoor environment and directions to a destination would greatly improve access and independence for people with low vision. This paper describes the construction of such a device which utilizes a commercial Ultra-Wideband (UWB) asset tracking system to support real-time location and navigation information. Human trials were conducted to assess the efficacy of the system by comparing target-finding performance between blindfolded subjects using the navigation system for real-time guidance, and blindfolded subjects who only received speech information about their local surrounds but no route guidance information (similar to that available from a long cane or guide dog). A normal vision control condition was also run. The time and distance traveled was measured in each trial and a point-back test was performed after goal completion to assess cognitive map development. Statistically significant differences were observed between the three conditions in time and distance traveled; with the navigation system and the visual condition yielding the best results, and the navigation system dramatically outperforming the non-guided condition. PMID:19163698
In-field calibration of the Navigation Dosimetry System (NAVIDOS) during solar minimum conditions
NASA Astrophysics Data System (ADS)
M�ller, T.; Burda, O.; Burmeister, S.; Heber, B.; Langner, F.; Wissmann, F.
The NAVIgation DOsimetry System (NAVIDOS) comprises a complete readout system for a radiation detector, an air pressure sensor and a GPS receiver. The detector system DOSTEL uses silicon detectors which make NAVIDOS light weighted and compact in size. Therefore, NAVIDOS is well suited to be installed on board aircraft. The calibration of NAVIDOS in terms of ambient dose equivalent is done by an in-field comparison with the PTB reference instrument ?DOS. We also show that the dependence of these results on the vertical cut-off rigidity can be explained by the low response of the silicon detectors for neutrons. Therefore, in-flight measurements have been performed together with the PTB reference instrument ?DOS. The dose rates, calculated using the PTB code FDOScalc, were verified with these ?DOS measurements. The calibration of NAVIDOS was done with FDOScalc and results in calibration factors between 3.4 in the polar and 2.4 in the equator region.
Carrier phase based DGPS systems have been used for airborne mapping for many years. Integrated GPS\\/INS systems are also becoming popular in order to improve the positioning accuracy, system reliability and achieve direct geo-referencing. However, this approach is limited by the current GPS constellation. Further improvement is required to achieve centimetre level positioning accuracy, which becomes increasingly important for large
A navigational guidance system in the human brain
Spiers, Hugo J.; Maguire, Eleanor A.
Finding your way in large-scale space requires knowing where you currently are and how to get to your goal destination. While much is understood about the neural basis of one�s current position during navigation, surprisingly little is known about how the human brain guides navigation to goals. Computational accounts argue that specific brain regions support navigational guidance by coding the proximity and direction to the goal, but empirical evidence for such mechanisms is lacking. Here, we scanned subjects with functional MRI (fMRI) as they navigated to goal destinations in a highly accurate virtual simulation of a real city. Brain activity was then analysed in combination with metric measures of proximity and direction to goal destinations which were derived from each individual subject�s coordinates at every second of navigation. We found that activity in the medial prefrontal cortex was positively correlated, and activity in a right subicular/entorhinal region was negatively correlated with goal proximity. By contrast, activity in bilateral posterior parietal cortex was correlated with egocentric direction to goals. Our results provide empirical evidence for a navigational guidance system in the human brain, and define more precisely the contribution of these three brain regions to human navigation. In addition, these findings may also have wider implications for how the brain monitors and integrates different types of information in the service of goal-directed behaviour in general. PMID:17492693
Causal Analysis Methodology of Multisensor Systems based on GNSS
Boyer, Edmond
(Global Navigation Satellite Sys- tems) like the GPS (Global Positioning System) or the future Galileo Systems) - the GPS (Global Positioning System) - was designed by the DoD (Department of Defense) of United
The time keeping system for GPS block IIR
NASA Technical Reports Server (NTRS)
Rawicz, H. C.; Epstein, M. A.; Rajan, J. A.
The precision time keeping system (TKS) in the Global Positioning System (GPS), Block IIR satellites is designed to operate under severe natural and man made environmental conditions. The Block IIR TKS provides precise, autonomous time keeping for periods of up to seven months, without the intervention of the GPS Control Segment. The TKS is implemented using both linear and non-linear controls. The resulting TKS architecture uses a hybrid analog/digital phase locked loop (PLL). The paper provides details of the design and analysis of the TKS. The simulation techniques and the test bed activities used in performing the TKS design trade-offs are described. The effects of non-linear controls are analyzed using a TKS computer simulation of the PLL. The results from a hardware test bed are provided that verify desired TKS operation. The design criteria for the TKS computer simulation and the hardware test bed are indicated. The concepts for verification and testing of the TKS computer simulation and hardware test bed are presented.
Synthetic Aperture Digital Beamsteering Array for Global Positioning System Interference Mitigation: A Study on Array Topology
Harms, Joel K
The Global Positioning System (GPS) satellite navigation system is deeply intertwined with civilian everyday life. Unfortunately for the civilians that use the system, the GPS system is vulnerable to external interference. Antenna arrays...
Synthetic Aperture Digital Beamsteering Array for Global Positioning System Interference Mitigation: A Study on Array Topology�
Harms, Joel K
The Global Positioning System (GPS) satellite navigation system is deeply intertwined with civilian everyday life. Unfortunately for the civilians that use the system, the GPS system is vulnerable to external interference. Antenna arrays...
BeiDou Navigation Satellite System and its time scales
Chunhao Han; Yuanxi Yang; Zhiwu Cai
The development and current status of BeiDou Navigation Satellite System are briefly introduced. The definition and realization of the system time scales are described in detail. The BeiDou system time (BDT) is an internal and continuous time scale without leap seconds. It is maintained by the time and frequency system of the master station. The frequency accuracy of BDT is
Using Ontologies for Adaptive Navigation Support in Educational Hypermedia Systems
Pythagoras Karampiperis; Demetrios Sampson
Educational hypermedia systems seek to provide adaptive naviga- tion, whereas intelligent web-based learning systems seek to provide adaptive courseware generation. The design of powerful frameworks by merging the ap- proaches used in the above mentioned systems is recognized as one of the most interesting questions in adaptive web-based educational systems. In this paper we address adaptive navigation support in educational
Pharos: coupling GSM and GPS-TALK technologies to provide orientation, navigation and location-based services for the blind
A. Marsh; M. May; M. Saarelainen
Millions of people are already experiencing with GSM the freedom of going mobile for voice and Internet access. This freedom is reshaping every aspect of our lives; the way we do business, the way we buy things and the way we communicate. For the blind, when combined with GPS, it could also add the freedom of movement. The paper considers
Precise navigation for the Earth Observing System (EOS)-AM1 spacecraft using the TDRSS Onboard Navigation System (TONS)
NASA Technical Reports Server (NTRS)
Folta, David C.; Elrod, Bryant; Lorenz, Mark; Kapoor, Ajay
As the baseline navigation system for the Earth Observing System (EOS)-AM1 spacecraft, the Tracking and Data Relay Satellite System (TDRSS) Onboard Navigation System (TONS) is required to provide precise position and velocity information for imaging instrument calibration and routine operations. This paper presents the results of real-time navigation performance evaluations with respect to TONS-based orbit and frequency determination to satisfy this requirement. Both covariance and simulation analysis of EOS-AM1 navigation accuracy and analysis using operational data from Landsat-4 are presented. Local (half orbit) and global (multiple orbits) tracking are considered using a way-forward link services. Improvements in navigation accuracies by using enhanced gravity models beyond the Goddard Earth Model (GEM)-T3 are also discussed. Key objectives of the analysis are to evaluate nominal performance and potential sensitivities and to address algorithm improvements such as TDRS ephemeris biasing, ionosphere model, and gravity process noise models slated for implementation. Results indicate that TONS can be configured to meet the proposed instrument navigation requirements of 20 meters, 3-sigma.
Precise navigation for the Earth Observing System (EOS)-AM1 spacecraft using the TDRSS Onboard Navigation System (TONS)
NASA Astrophysics Data System (ADS)
Folta, David C.; Elrod, Bryant; Lorenz, Mark; Kapoor, Ajay
As the baseline navigation system for the Earth Observing System (EOS)-AM1 spacecraft, the Tracking and Data Relay Satellite System (TDRSS) Onboard Navigation System (TONS) is required to provide precise position and velocity information for imaging instrument calibration and routine operations. This paper presents the results of real-time navigation performance evaluations with respect to TONS-based orbit and frequency determination to satisfy this requirement. Both covariance and simulation analysis of EOS-AM1 navigation accuracy and analysis using operational data from Landsat-4 are presented. Local (half orbit) and global (multiple orbits) tracking are considered using a way-forward link services. Improvements in navigation accuracies by using enhanced gravity models beyond the Goddard Earth Model (GEM)-T3 are also discussed. Key objectives of the analysis are to evaluate nominal performance and potential sensitivities and to address algorithm improvements such as TDRS ephemeris biasing, ionosphere model, and gravity process noise models slated for implementation. Results indicate that TONS can be configured to meet the proposed instrument navigation requirements of 20 meters, 3-sigma.
J. Traugott; G. Sachs; O. Montenbruck
A stand-alone method for precise navigation based on sin- gle time-di erences of L1 phase observations is presented. The approach is applied to raw data of miniaturized, low- cost GPS receivers as used in car navigation systems or modern handheld devices. The basic equations describ- ing the observables and the navigation algorithm are de- rived. Further, a logic for processing
Design of the Embedded Navigation System of Autonomous Underwater Vehicle based on the VxWorks
Yushan Sun; Lei Wan; Xiao Liang; Yongjie Pang
The embedded navigation system of autonomous underwater vehicle is introduced, which includes navigation overall architecture, hardware and software structure. The navigation system based on PC104 bus adopts the VxWorks system, which is a powerful real-time operating system. Intel PIIX-4 is used as the navigation controller's CPU. Meanwhile, the whole information flow of the navigation system is also discussed in this
Application of data fusion in multi-sensor integrated navigation system
Xu Jinsong; Lu Xiaochun; Wu Haitao; Bian Yujing; Zou Decai
Integrated navigation system can help to solve the performance and application problems and limitations of the navigation equipment. Data fusion technology is one of the kernel parts in integrated navigation systems. In this paper, the current advances of this technology are introduced, with the architecture of a multi-sensor navigation system given and its principles and structure presented in detail. The
Evaluation of the 1984 Alaska global positioning system campaign with the Bernese GPS software
G. Beutler; I. Bauersima; W. Gurtner; M. Rothacher; T. Schildknecht; G. L. Mader; M. D. Abell
During the summer of 1984 five TI-4100 global positioning system (GPS) receivers were used to measure an eight-station network in Alaska and Canada, previously measured with mobile very long baseline interferometry (VLBI) systems, with baselines ranging from 300 km to almost 2700 km. The observations have been processed in the network mode with the Bernese GPS software using orbit improvement
NAVIGATOR: Autonomous navigation system for planetary exploration landers based on stereo vision
NASA Astrophysics Data System (ADS)
Guizzo, G. P.; Angrilli, F.; Vukman, I.
This generation of lander navigation system was born in order to cover a wide spectrum of soft landing scenarios on planets like Mars, Mercury or the Moon; it is also particularly useful when there is no a priori knowledge of the ground. The navigation system studied here is completely autonomous and able to land on various kinds of hazardous terrains with many unevennesses like mountain tops, bottoms of illuminated craters, valleys or small plateaus. In order to choose an adequate site for landing the navigation system uses stereo image pairs, obtained with a single camera at high altitudes and with two cameras at lower ones, to produce a digital elevation model (DEM) of the terrain. It uses dense disparity maps, made from the sign-of-laplacian-of-gaussian (SLOG) of the images, as input for the vertical locus method. This technique takes the advantage of a fast and easy processing of the image since it is possible to implement the required algorithms in a efficient way by the use of an ASIC. A DSP is then used for the remaining software operations, i.e. piloting and guidance of the lander. Another advantage of this method is that, unlike most methods involving active sensors, it can be used even with the camera at great distances to the target (e.g. at the beginning of the approach phase) since it is limited only by the camera field of view and resolution. It moreover doesn't rely on any special features of the terrain, like craters, rocks or other landmarks, but it is sufficient to have an illuminated and slightly textured terrain. The navigation system validation was done using a synthetic terrain generator which allowed the closed-loop simulation of the entire system.
A goggle navigation system for cancer resection surgery
NASA Astrophysics Data System (ADS)
Xu, Junbin; Shao, Pengfei; Yue, Ting; Zhang, Shiwu; Ding, Houzhu; Wang, Jinkun; Xu, Ronald
We describe a portable fluorescence goggle navigation system for cancer margin assessment during oncologic surgeries. The system consists of a computer, a head mount display (HMD) device, a near infrared (NIR) CCD camera, a miniature CMOS camera, and a 780 nm laser diode excitation light source. The fluorescence and the background images of the surgical scene are acquired by the CCD camera and the CMOS camera respectively, co-registered, and displayed on the HMD device in real-time. The spatial resolution and the co-registration deviation of the goggle navigation system are evaluated quantitatively. The technical feasibility of the proposed goggle system is tested in an ex vivo tumor model. Our experiments demonstrate the feasibility of using a goggle navigation system for intraoperative margin detection and surgical guidance.
Application of differential GPS to civil helicopter terminal guidance
NASA Technical Reports Server (NTRS)
Denaro, R. P.
NASA is conducting a research program to evaluate differential Global Positioning System (GPS) concepts for civil helicopter navigation. It is pointed out that the civil helicopter community will probably be an early user of GPS because of the unique mission operations in areas where precise navigation aids are not available. Applications with very demanding accuracy requirements are related to remote area search and rescue, offshore oil platform approach, remote area precision landing, and other precise navigation operations. Differential GPS appears to provide a solution for meeting the accuracy requirements involved in the considered operations. The present investigation is concerned with results obtained in three areas studied in connection with the conducted research program. Attention is given to mission-tailored satellite selection, a satellite selection algorithm concept, satellite selection algorithm simulation results, and differential GPS ground station design.
Vision-based augmented reality computer assisted surgery navigation system
NASA Astrophysics Data System (ADS)
Sun, Lei; Chen, Xin; Xu, Kebin; Li, Xin; Xu, Wei
A vision-based Augmented Reality computer assisted surgery navigation system is presented in this paper. It applies the Augmented Reality technique to surgery navigation system, so the surgeon's vision of the real world is enhanced. In the system, the camera calibration is adopted to calculate the cameras projection matrix, and then make the virtual-real registration by using the transformation relation. The merging of synthetic 3D information into user's vision is realized by texture technique. The experiment results demonstrate the feasibility of the system we have designed.
The OPERA global readout and GPS distribution system
NASA Astrophysics Data System (ADS)
Marteau, J.; Opera Collaboration
OPERA is an experiment dedicated to the observation of ?? into ?? oscillations in appearance mode using a pure ?? beam (CNGS) produced at CERN and detected at Gran Sasso. The experiment exploits a hybrid technology with emulsions and electronics detectors. The OPERA readout is performed through a triggerless, continuously running, distributed and highly available system. Its global architecture is based on Ethernet-capable smart sensors with microprocessing and network interface directly at the front-end stage. A unique interface board is used for the full detector reading out ADC-, TDC- or Controller-boards. All the readout channels are synchronized through a GPS-locked common bidirectional clock distribution system developed on purpose in a PCI format. It offers a second line to address all channels and the off-line synchronization with the CNGS to select the events.
High-accuracy, high-frequency differential carrier phase GPS aided low-cost INS
Yunchun Yang; Jay Farrell; Matt Barth
This article describes experimental results for a real-time, carrier phase, differential Global Positioning System (GPS) aided inertial navigation system (INS). The INS uses inexpensive solid state inertial sensors sampled and integrated at 150 Hz with differential GPS carrier phase measurements as corrections via a complementary filter at 1 Hz. Therefore, the implementation achieves 150 Hz, vehicle state estimates with position
Vision-aided inertial navigation system for robotic mobile mapping
Fadi A. Bayoud; Jan Skaloud
A mapping system by vision-aided inertial navigation was developed for areas where GNSS sig- nals are unreachable. In this framework, a methodol- ogy on the integration of vision and inertial sensors is presented, analysed and tested. The system employs the method of ''SLAM: Simultaneous Localisation And Mapping'' where the only external input avail- able to the system at the beginning
A stereo camera system for autonomous maritime navigation (AMN) vehicles
Weihong Zhang; Ping Zhuang; Les Elkins; Rick Simon; David Gore; Jeff Cogar; Kevin Hildebrand; Steve Crawford; Joe Fuller
Spatial Integrated System (SIS), Rockville, Maryland, in collaboration with NSWC Combatant Craft Division (NSWCCD), is applying 3D imaging technology, artificial intelligence, sensor fusion, behaviors-based control, and system integration to a prototype 40 foot, high performance Research and Development Unmanned Surface Vehicle (USV). This paper focus on the developments of the stereo camera system in the USV navigation that currently consists
Usability of apple iPhones for inertial navigation systems
Corina Kim Schindhelm; Florian Gschwandtner; Michael Banholzer
In recent decades, many indoor positioning techniques have been researched and some approaches have even been developed into consumer products. Most of them have been deployed into companies which benefit from indoor asset tracking. However, for public buildings like libraries or transportation systems, no direct benefit exists by installing expensive systems. Inertial navigation systems offer a form of positioning which
Global positioning system pseudolite-based relative navigation.
Monda, Eric W. (University of Texas, Austin, TX)
Though the Global Positioning System has revolutionized navigation in the modern age, it is limited in its capability for some applications because an unobstructed line of sight to a minimum of four satellites is required. One way of augmenting the system in small areas is by employing pseudolites to broadcast additional signals that can be used to improve the user's position solution. At the Navigation Systems Testing Laboratory (NSTL) at NASA's Johnson Space Center in Houston, TX, research has been underway on the use of pseudolites to perform precision relative navigation. Based on the findings of previous research done at the NSTL, the method used to process the pseudolite measurements is an extended Kalman filter of the double differenced carrier phase measurements. By employing simulations of the system, as well as processing previously collected data in a real time manner, sub-meter tracking of a moving receiver with carrier phase measurements in the extended Kalman filter appears to be possible.
An Application of UAV Attitude Estimation Using a Low-Cost Inertial Navigation System
NASA Technical Reports Server (NTRS)
Eure, Kenneth W.; Quach, Cuong Chi; Vazquez, Sixto L.; Hogge, Edward F.; Hill, Boyd L.
Unmanned Aerial Vehicles (UAV) are playing an increasing role in aviation. Various methods exist for the computation of UAV attitude based on low cost microelectromechanical systems (MEMS) and Global Positioning System (GPS) receivers. There has been a recent increase in UAV autonomy as sensors are becoming more compact and onboard processing power has increased significantly. Correct UAV attitude estimation will play a critical role in navigation and separation assurance as UAVs share airspace with civil air traffic. This paper describes attitude estimation derived by post-processing data from a small low cost Inertial Navigation System (INS) recorded during the flight of a subscale commercial off the shelf (COTS) UAV. Two discrete time attitude estimation schemes are presented here in detail. The first is an adaptation of the Kalman Filter to accommodate nonlinear systems, the Extended Kalman Filter (EKF). The EKF returns quaternion estimates of the UAV attitude based on MEMS gyro, magnetometer, accelerometer, and pitot tube inputs. The second scheme is the complementary filter which is a simpler algorithm that splits the sensor frequency spectrum based on noise characteristics. The necessity to correct both filters for gravity measurement errors during turning maneuvers is demonstrated. It is shown that the proposed algorithms may be used to estimate UAV attitude. The effects of vibration on sensor measurements are discussed. Heuristic tuning comments pertaining to sensor filtering and gain selection to achieve acceptable performance during flight are given. Comparisons of attitude estimation performance are made between the EKF and the complementary filter.
Edmundo A. Marques Filho; H�lio Koiti Kuga; Roberto V. F. Lopes
The global positioning system (GPS) is a one-way, all-weather, real time, and world-wide radio navigation system whose main purpose is to provide a GPS dedicated receiver with a signal that allows a user to compute accurately and in real-time the longitude, latitude, altitude and precise time. Since precise time is an integral part of GPS, a large community of precise
The navigation system of the JPL robot
NASA Technical Reports Server (NTRS)
Thompson, A. M.
The control structure of the JPL research robot and the operations of the navigation subsystem are discussed. The robot functions as a network of interacting concurrent processes distributed among several computers and coordinated by a central executive. The results of scene analysis are used to create a segmented terrain model in which surface regions are classified by traversibility. The model is used by a path planning algorithm, PATH, which uses tree search methods to find the optimal path to a goal. In PATH, the search space is defined dynamically as a consequence of node testing. Maze-solving and the use of an associative data base for context dependent node generation are also discussed. Execution of a planned path is accomplished by a feedback guidance process with automatic error recovery.
A T-DMB navigation system for seamless positioning in both indoor and outdoor environments
NASA Astrophysics Data System (ADS)
Moon, Gong Bo; Chun, Se Bum; Hur, Moon Beom; Jee, Gyu-In
The conventional global positioning system (GPS) can often fail to provide position determination for a mobile user in indoor and urban environments. To cope with GPS failure in such environments, a new navigation system which utilizes a terrestrial digital multimedia broadcasting (T-DMB) signal to obtain the mobile user's position is presented. Since the T-DMB transmitters in Korea construct a single frequency network (SFN), which forces the transmitters to be synchronized, the mobile user can measure a time difference of arrival (TDOA) for all audible T-DMB transmitter pairs. The time difference between T-DMB transmitters is converted to a distance difference by multiplying the time difference by the speed of light. Using these measurements and a TDOA positioning method, the mobile user position can be estimated. An experiment with a T-DMB receiver and a data acquisition (DAQ) board is performed in Seoul to analyze the error characteristic of TDOA measurements. It is certified that the measurement error is bounded under 300 m and can be used to determine the mobile user's position with a small standard deviation.
Wakeshield WSF-02 GPS Experiment
NASA Technical Reports Server (NTRS)
Schutz, B. E.; Abusali, P. A. M.; Schroeder, Christine; Tapley, Byron; Exner, Michael; Mccloskey, rick; Carpenter, Russell; Cooke, Michael; Mcdonald, samantha; Combs, Nick; Duncan, Courtney; Dunn, Charles; Meehan, Tom
Shuttle mission STS-69 was launched on September 7, 1995, 10:09 CDT, carrying the Wake Shield Facility (WSF-02). The WSF-02 spacecraft included a set of payloads provided by the Texas Space Grant Consortium, known as TexasSat. One of the TexasSat payloads was a GPS TurboRogue receiver loaned by the University Corporation for Atmospheric Research. On September 11, the WSF-02 was unberthed from the Endeavour payload bay using the remote manipulator system. The GPS receiver was powered on prior to release and the WSF-02 remained in free-flight for three days before being retrieved on September 14. All WSF-02 GPS data, which includes dual frequency pseudorange and carrier phase, were stored in an on-board recorder for post-flight analysis, but "snap- shots" of data were transmitted for 2-3 minutes at intervals of several hours, when permitted by the telemetry band- widdl The GPS experiment goals were: (1) an evaluation of precision orbit determination in a low altitude environment (400 km) where perturbations due to atmospheric drag and the Earth's gravity field are more pronounced than for higher altitude satellites with high precision orbit requirements, such as TOPEX/POSEIDON; (2) an assessment of relative positioning using the WSF GPS receiver and the Endeavour Collins receiver; and (3) determination of atmospheric temperature profiles using GPS signals passing through the atmosphere. Analysis of snap-shot telemetry data indicate that 24 hours of continuous data were stored on board, which includes high rate (50 Hz) data for atmosphere temperature profiles. Examination of the limited number of real-time navigation solutions show that at least 7 GPS satellites were tracked simultaneously and the on-board clock corrections were at the microsec level, as expected. Furthermore, a dynamical consistency test provided a further validation of the on-board navigation solutions. Complete analysis will be conducted in post-flight using the data recorded on-board.
Analysis of a choke ring groundplane for multipath control in Global Positioning System (GPS) applications
James M. Tranquilla; J. P. Carr; Hussain M. Al-Rizzo
In this paper a computational scheme is presented for accurately predicting the farfield amplitude and phase characteristics of Global Positioning System (GPS) antennas flush-mounted to a corrugated groundplane. The algorithm developed is particularly well-suited in beamshaping of (GPS) antennas in order to provide a high level of multipath rejection. The usefulness of the analytical model has been verified by the
Global Positioning System (GPS) estimates of crustal deformation in the Marmara Sea region, Northwestern Anatolia
Christian Straub; Hans-Gert Kahle
In the Marmara Sea region the relative motion between the Anatolian and Eurasian lithosphere has been measured by means of the modern techniques of space geodesy using the Global Positioning System (GPS). In order to resolve in detail the kinematic field within the active earthquake belts of Northwestern Anatolia, two GPS campaigns were carried out across a dense network consisting
Global Positioning System (GPS) location accuracy improvement due to Selective Availability removal
Christophe Adrados; Ir�ne Girard; Jean-Paul Gendner; Georges Janeau
Global Positioning System (GPS) is an important new technology for spatio-temporal behaviour studies of animals. Differential correction improves location accuracy. Previously, it mostly removed partially the influence of Selective Availability (SA). SA was deactivated in May 2000. The aim of this study was to quantify the influence of SA cancellation on location accuracy of various GPS receivers. We tested the
Integrating Inertial Sensors With Global Positioning System (GPS) for Vehicle Dynamics Control
Jihan Ryu; J. Christian Gerdes
This paper demonstrates a method of estimating several key vehicle states�sideslip angle, longitudinal velocity, roll and grade�by combining automotive grade inertial sen- sors with a Global Positioning System (GPS) receiver. Kinematic Kalman filters that are independent of uncertain vehicle parameters integrate the inertial sensors with GPS to provide high update estimates of the vehicle states and the sensor biases. Using
Theoretical description of a bistatic system for ocean altimetry using the GPS signal
George A. Hajj; Cinzia Zuffada
This paper presents the fundamental characteristics of bistatic altimetry performed using the Global Positioning System (GPS) signal scattered off the ocean surface and collected by a receiver in space. The advantage of the dense and rapid surface coverage afforded by the existing GPS constellation would enable new oceanographic applications such as eddy monitoring and the tracking of fast barotropic waves.
SYNERGY SYSTEMS TECH-NOTE #489 XTS/II GPS Sensor Engineering Evaluation Kits
Berns, Hans-Gerd
SYNERGY SYSTEMS TECH-NOTE #489 XTS/II GPS Sensor Engineering Evaluation Kits Revised: June 23, 1998 The XTS/II series of OEM GPS Sensors, when combined with appropriate accessories, can form a full Engi- neering Evaluation Kit. The kit may be used for testing and developing products based on the Motorola
Development of an Integrated Low-Cost GPS\\/Rate Gyro System for Attitude Determination
Chaochao Wang; G�rard Lachapelle; M. Elizabeth Cannon
The use of low-cost GPS receivers and antennas for attitude determination can significantly reduce the overall hardware system cost. Compared to the use of high performance GPS receivers, the carrier phase measurements from low-cost equipment are subject to additional carrier phase measurement errors, such as multipath, antenna phase centre variation and noise. These error sources, together with more frequent cycle
A Reactive System For Off-Road Navigation
D. Langer; J. K. Rosenblatt; M. Hebert
In this paper; we describe a core system for autonomous navigation in outdoor natural ter- rain. The system consists of three parts: a perception module which processes range images to identify untraversable regions of the terrain, a local map management module which main- tains a representation of the environment in the vicinity of the vehicle, and a planning module which
Taux: A System for Evaluating Sound Feedback in Navigational Tasks
ERIC Educational Resources Information Center
Lutz, Robert J.
This thesis presents the design and development of an evaluation system for generating audio displays that provide feedback to persons performing navigation tasks. It first develops the need for such a system by describing existing wayfinding solutions, investigating new electronic location-based methods that have the potential of changing these�
The Taxiway Navigation and Situation Awareness (T-NASA) System
NASA Technical Reports Server (NTRS)
Foyle, David C.; Sridhar, Banavar (Technical Monitor)
The goal of NASA's Terminal Area Productivity (TAP) Low-Visibility Landing and Surface Operations (LVLASO) subelement is to improve the efficiency of airport surface operations for commercial aircraft operating in weather conditions to Category IIIB while maintaining a high degree of safety. Currently, surface operations are one of the least technologically sophisticated components of the air transport system, being conducted in the 1990's with the same basic technology as in the 1930's. Pilots are given little or no explicit information about their current position, and routing information is limited to ATC communications and airport charts. In TAP/LVLASO, advanced technologies such as satellite navigation systems, digital data communications, advanced information presentation technology, and ground surveillance systems will be integrated into flight deck displays to enable expeditious and safe traffic movement on the airport surface. The cockpit display suite is called the T-NASA (Taxiway Navigation and Situation Awareness) System. This system has three integrated components: 1) Moving Map track-up airport surface display with own-ship, traffic and graphical route guidance 2) Scene-Linked Symbology - route/taxi information virtually projected via a Head-up Display (HUD) onto the forward scene; and, 3) 3-D Audio Ground Collision Avoidance and Navigation system - spatially-localized auditory traffic and navigation alerts. In the current paper, the design philosophy of the T-NASA system will be presented, and the T-NASA system display components described.
GPS error and its effects on movement analysis
Ranacher, Peter; Van der Spek, Stefan Christiaan; Reich, Siegfried
Global Navigation Satellite Systems (GNSS), such as the Global Positioning System (GPS), are among the most important sensors in movement analysis. GPS data loggers are widely used to record the movement trajectories of vehicles, animals or human beings. However, these trajectories are inevitably affected by GPS measurement error, which influences conclusion drawn about the behavior of the moving objects. In this paper we investigate GPS measurement error and discuss its influence on movement parameters such as speed, direction or distance. We identify three characteristic properties of GPS measurement error: it follows temporal (1) and spatial (2) autocorrelation and causes a systematic overestimation of distances (3). Based on our findings we give recommendations on how to collect movement data in order to minimize the influence of error. We claim that these recommendations are essential for designing an appropriate sampling strategy for collecting movement data by means of a GPS.
Vehicle health management for guidance, navigation and control systems
Kathleen Radke; Ron Frazzini; Paul Bursch; Jerry Wald; Don Brown
The objective of the program was to architect a vehicle health management (VHM) system for space systems avionics that assures system readiness for launch vehicles and for space-based dormant vehicles. The platforms which were studied and considered for application of VHM for guidance, navigation and control (GN&C) included the Advanced Manned Launch System (AMLS), the Horizontal Landing-20\\/Personnel Launch System (HL-20\\/PLS),
A worldwide unification of GPS (Global Positioning System) antenna coordinates for high accuracy time transfer.
NASA Astrophysics Data System (ADS)
Lewandowski, W.
In the present state of the art of atomic clocks it is desirable that comparisons of these clocks, located in the time metrology laboratories spread around the world, be at the level of a few nanoseconds of accuracy. At present the sole operational way to provide such performance is through the system of GPS satellites. As GPS is a one-way system this implies that special attention must be given to geometrical errors. In order to achieve nanosecond accuracy, the error due to the ground-antenna coordinates should not exceed 1 ns in the global budget of errors of GPS time transfer. To attain this goal the ground-antenna coordinates must be accurately determined in a common worldwide homogeneous geodetic reference frame with uncertainties of order 30 cm. This paper considers the choice of a global reference frame for accurate GPS time transfer and then reports on a worldwide homogenization of GPS antenna coordinates in the principal timing centres.
Precise time and Time Interval (PTTI) measurements from the navigation technology satellites and the GPS NAVSTAR-4 satellite
NASA Technical Reports Server (NTRS)
Buisson, J. A.; Mccaskill, T., B.; Oaks, O. J.; Jeffries, M. M.; Stebbins, S. B.
A time domain estimate for the NAVSTAR-4 SV clock offset was obtained for each SV pass over the GPS monitor sites, using a smoothed reference ephemeris, with corrections for ionospheric delay, tropospheric delay, earth rotation and relativistic effects. Conversion from the time domain to the frequency domain was made using the two sample Allan Variance; sigma-tau plots used to identify the noise processes. Estimates of flicker and white frequency noise for the NAVSTAR-4 rubidium frequency standard were obtained. The contribution of the reference ground clocks and other error sources to the frequency stability estimates were also considered.
New approaches for tracking earth orbiters using modified GPS ground receivers
S. M. Lichten; L. E. Young; S. Nandi; B. J. Haines; C. E. Dunn; C. D. Edwards
A Global Positioning System (GPS) flight receiver provides a means to precisely determine orbits for satellites in low to moderate altitude orbits. Above a 5000-km altitude, however, relatively few GPS satellites are visible. New approaches to orbit determination for satellites at higher altitudes could reduce DSN antenna time needed to provide navigation and orbit determination support to future missions. Modification
GPS Augmentation with Pseudolites for
Calgary, University of
GPS Augmentation with Pseudolites for Navigation in Constricted Waterways T. MORLEY Stanford transmitters, or pseudolites (PLs) (pseudo- satellites), to augment the existing space-borne GPS satellite the effect of increasing mask angle on GPS availability, accuracy, and reliability measures. Up to three PLs
Data Analysis Techniques for a Lunar Surface Navigation System Testbed
NASA Technical Reports Server (NTRS)
Chelmins, David; Sands, O. Scott; Swank, Aaron
NASA is interested in finding new methods of surface navigation to allow astronauts to navigate on the lunar surface. In support of the Vision for Space Exploration, the NASA Glenn Research Center developed the Lunar Extra-Vehicular Activity Crewmember Location Determination System and performed testing at the Desert Research and Technology Studies event in 2009. A significant amount of sensor data was recorded during nine tests performed with six test subjects. This paper provides the procedure, formulas, and techniques for data analysis, as well as commentary on applications.
Wireless GPS system for module fiber quality mapping: System improvement and field testing
Technology Transfer Automated Retrieval System (TEKTRAN)
A wireless GPS system for module-level fiber quality mapping has been developed at Texas A&M University. In its complete form, it includes subsystems for harvesters, boll buggies, and module builders. The system was field tested on a producer's farm near Plains, Texas, in 2006. The field test identi...
Wireless GPS system for module-level fiber quality mapping: System improvement and field testing
Technology Transfer Automated Retrieval System (TEKTRAN)
A wireless GPS system for module-level fiber quality mapping has been developed at Texas A&M University. In its complete form, it includes subsystems for harvesters, boll buggies, and module builders. The system was field tested on a producer�s farm near Plains, Texas, in 2006. The field test identi...
Development of A Dental Implant Navigation System in Thailand
Jackrit Suthakorn; Auranuch Lorsakul; Chanjira Sinthanayothin; Wichit Tharanont
4 PURPOSE: Dental implant is one of the most popular methods of tooth root replacement used in prosthetic dentistry. Computerize navigation system on a pre-surgical plan is offered to minimize potential risk of damage to critical anatomic structures of patients. The methodology is based on Computer Integrated Surgery (CIS) interventions which includes preoperative and intraoperative procedures. The preoperative surgery requires
A MVC prototype for the landmarke firefighter navigation system
Beigl, Michael
A MVC prototype for the landmarke firefighter navigation system Markus Scholz, Leonardo Ramirez Berning, Matthias Budde, Dimana Shishkova, Till Riedel and Michael Beigl I. INTRODUCTION FirefightersIT@Work project was to search for alternative approaches to support firefighters. From their work
Robert W. Hosken; James R. Wertz
This paper describes the operation of the Microcosm Autonomous Navigation System (MANS) which was launched as an Air Force Phillips Laboratory Technology for Autonomous Operational Survivability -(TAOS) experimental payload on March 13, 1994. MANS determines the position, velocity, attitude, attitude rate, ground look point, and lighting conditions of the host satellite. As implemented on TAOS, MANS uses two opposite facing
Instrumental laser beam systems in navigation using scattered radiation
Victor G. Oshlakov
Molecular and aerosol scattering of laser radiation, propagating in the atmosphere, makes it possible to visualize it in space. This phenomenon can be used for navigation in the navy, air force and astronautics. The laser radiation scattering is known to be used in the visual laser beam systems. The scattered laser radiations is small as compared with direct laser radiation
NATO SET-168 Symposium Navigation Sensors and Systems in GNSS Denied Environments, Izmir, Turkey, 8-9Oct12 PERFORMANCE OF PEDESTRIAN NAVIGATION SYSTEMS AS A
Calgary, University of
. In many military, offender tracking and safety of life pedestrian navigation applications, the inertial, Izmir, Turkey, 8-9Oct12 PERFORMANCE OF PEDESTRIAN NAVIGATION SYSTEMS AS A FUNCTION OF SENSOR sensors in pedestrian navigation are becomingly more common. The ability to apply Kalman filter updates
Triply redundant integrated navigation and asset visibility system
Smith, Stephen F.; Moore, James A.
Methods and apparatus are described for a navigation system. A method includes providing a global positioning system fix having a plurality of tracking parameters; providing a theater positioning system fix; monitoring the plurality of tracking parameters for predetermined conditions; and, when the predetermined conditions are met, sending a notifying signal and switching to the theater positioning system fix as a primary fix. An apparatus includes a system controller; a global positioning system receiver coupled to the system controller; a radio frequency locating receiver coupled to the system controller; and an operator interface coupled to the system controller.
Triply redundant integrated navigation and asset visibility system
Smith, Stephen F. (Loudon, TN); Moore, James A. (Powell, TN)
Methods and apparatus are described for a navigation system. A method includes providing a global positioning system fix having a plurality of tracking parameters; providing a theater positioning system fix; monitoring the plurality of tracking parameters for predetermined conditions; and, when the predetermined conditions are met, sending a notifying signal and switching to the theater positioning system fix as a primary fix. An apparatus includes a system controller; a global positioning system receiver coupled to the system controller; a radio frequency locating receiver coupled to the system controller; and an operator interface coupled to the system controller.
Vision aided navigation for unmanned helicopters
Diomidis Katzourakis; Nikos I. Vitzilaios; Nikos C. Tsourveloudis
The development of a vision system to aid the autonomous navigation of an unmanned helicopter, primarily based on inertial sensors and GPS data, is presented. An unmanned helicopter has been equipped with appropriate sensors and a vision system fitted on a custom pan-tilt mechanism. Robust software, based on the Open Computer Vision Library (OpenCV), has been developed for handling images
Evaluating the velocity accuracy of an integrated GPS/INS system: Flight test results
Owen, T.E.; Wardlaw, R.
Verifying the velocity accuracy of a GPS receiver or an integrated GPS/INS system in a dynamic environment is a difficult proposition when many of the commonly used reference systems have velocity uncertainities of the same order of magnitude or greater than the GPS system. The results of flight tests aboard an aircraft in which multiple reference systems simultaneously collected data to evaluate the accuracy of an integrated GPS/INS system are reported. Emphasis is placed on obtaining high accuracy estimates of the velocity error of the integrated system in order to verify that velocity accuracy is maintained during both linear and circular trajectories. Three different reference systems operating in parallel during flight tests are used to independently determine the position and velocity of an aircraft in flight. They are a transponder/interrogator ranging system, a laser tracker, and GPS carrier phase processing. Results obtained from these reference systems are compared against each other and against an integrated real time differential based GPS/INS system to arrive at a set of conclusions about the accuracy of the integrated system.
Ideas for Future GPS Timing Improvements
NASA Technical Reports Server (NTRS)
Hutsell, Steven T.
Having recently met stringent criteria for full operational capability (FOC) certification, the Global Positioning System (GPS) now has higher customer expectations than ever before. In order to maintain customer satisfaction, and the meet the even high customer demands of the future, the GPS Master Control Station (MCS) must play a critical role in the process of carefully refining the performance and integrity of the GPS constellation, particularly in the area of timing. This paper will present an operational perspective on several ideas for improving timing in GPS. These ideas include the desire for improving MCS - US Naval Observatory (USNO) data connectivity, an improved GPS-Coordinated Universal Time (UTC) prediction algorithm, a more robust Kalman Filter, and more features in the GPS reference time algorithm (the GPS composite clock), including frequency step resolution, a more explicit use of the basic time scale equation, and dynamic clock weighting. Current MCS software meets the exceptional challenge of managing an extremely complex constellation of 24 navigation satellites. The GPS community will, however, always seek to improve upon this performance and integrity.
A High-Performance, High-Accuracy RTK GPS Machine Guiadance System
Hugh Baertlein; Bruce Carlson; Rod Eckels; Stacey Lyle; Steve Wilson
��As technology matures, Real Time Kinematic (RTK) global positioning system (GPS) receivers are providing increased performance\\u000a in accuracy, on-the-fly (OTF) initialization times, measurement speed, and latency. Leica's Dozer 2000 machine guidance system\\u000a combines an MC1000 GPS sensor, graphic intensive guidance software, a digital terrain model, and a digital site plan. Figure\\u000a 1 shows the operator's view of the system. The
The Global Positioning System (GPS) has become a widely used tool in geodetic studies of Earth. We review the principles of the applications of GPS to geodetic problems and discuss its applications to problems of global and regional geodesy. A global network of dual-frequency GPS receivers continuously tracks the GPS satellites and the data are distributed to globally accessible on-line
GPS/CAPS dual-mode software receiver
NASA Astrophysics Data System (ADS)
Ning, Chunlin; Shi, Huli; Hu, Chao
The positioning of the GPS or Chinese Area Positioning System (CAPS) software receiver was developed on a software receiver platform. The structure of the GPS/CAPS dual-mode software receiver was put forward after analyzing the differences in the satellite identification, ranging code, spread spectrum, coordinate system, time system, carrier band, and navigation data between GPS and CAPS. Based on Matlab software on a personal computer, baseband signal processing and positioning procedures were completed using real GPS and CAPS radio frequency signals received by two antennas. Three kinds of experiments including GPS positioning, CAPS positioning, and GPS/CAPS positioning were carried out. Stability and precision of the results were analyzed and compared. The experimental results show that the precision of CAPS is similar to that of GPS, while the positioning precision of the GPS/CAPS dual-mode software receiver is 1-2 m higher than that of CAPS or GPS. The smallest average variance of the positioning can be obtained by using the GPS/CAPS dual-mode software receiver.
On exact solutions of the multi-constellation GNSS navigation problem
Jyh-Ching Juang; Yung Fu Tsai
In Global Navigation Satellite System (GNSS) positioning, the receiver measures the pseudorange with respect to each observable\\u000a navigation satellite and determines the position and clock bias. In addition to the GPS, several other navigation satellite\\u000a constellations including Glonass, Galileo and Compass can\\/will also be used to provide positioning, navigation, and timing\\u000a information. The paper is concerned with the solvability of
High-Accurate Deformation Monitoring System Based on GPS and COMPASS
NASA Astrophysics Data System (ADS)
Xiao, Yugang; Jiang, Weiping; Xi, Ruijie; Peng, Lifeng
The results of deformation monitoring system can be significantly enhanced in accuracy and availability with multiple GNSS systems. Phase II of COMPASS has completed a constellation of 14 satellites, 5 GEO satellites, 5 IGSO satellites and 4 MEO satellites, before the end of 2012 and can provide navigation services in Asia-Pacific areas now. Along with the release of the Interface Control Document (ICD), there are more combinations for us to select. In this study, we have developed a new deformation monitoring system based on two GNSS systems, GPS and COMPASS, with the strategy of double-difference and a wide variety of systematic error corrections. During the process of research and development, reliable methods of data preprocessing and bias fixing were used. We took advantage of the geometry-free observables (LG), Melbourne-Wubbena observables (MW) and single-difference residuals of ionosphere-free observables (LC) to detect the cycle slips of raw data, and then solved all of these cycle slips as bias parameters in the process of Least Square Algorithm to avoid the wrong repairs. As for the bias fixing, We utilized the method of bootstrap and decision function to solve the bias parameters as an integer one by one. Several steps were adopted to ensure the result of bias fixing was correct. The solution was given by 3 components of the baselines and their variances respectively, which could be used to evaluate the quality of the data-processing. Comparisons between the new system and systems which is based on single GNSS system show that the results are improved remarkably in accuracy and availability, especially in Asia-Pacific region, where the accuracy of mm-level for short baselines can be achieved easily. Along with more satellites being launched in the future, COMPASS will make more contribution to the deformation monitoring application worldwide. In addition, the solution can be further enhanced with more and more error correction models being put into effect.
A Strapdown Interial Navigation System/Beidou/Doppler Velocity Log Integrated Navigation Algorithm Based on a Cubature Kalman Filter
Gao, Wei; Zhang, Ya; Wang, Jianguo
The integrated navigation system with strapdown inertial navigation system (SINS), Beidou (BD) receiver and Doppler velocity log (DVL) can be used in marine applications owing to the fact that the redundant and complementary information from different sensors can markedly improve the system accuracy. However, the existence of multisensor asynchrony will introduce errors into the system. In order to deal with the problem, conventionally the sampling interval is subdivided, which increases the computational complexity. In this paper, an innovative integrated navigation algorithm based on a Cubature Kalman filter (CKF) is proposed correspondingly. A nonlinear system model and observation model for the SINS/BD/DVL integrated system are established to more accurately describe the system. By taking multi-sensor asynchronization into account, a new sampling principle is proposed to make the best use of each sensor's information. Further, CKF is introduced in this new algorithm to enable the improvement of the filtering accuracy. The performance of this new algorithm has been examined through numerical simulations. The results have shown that the positional error can be effectively reduced with the new integrated navigation algorithm. Compared with the traditional algorithm based on EKF, the accuracy of the SINS/BD/DVL integrated navigation system is improved, making the proposed nonlinear integrated navigation algorithm feasible and efficient. PMID:24434842
75 FR 1080 - Certain Automotive Multimedia Display and Navigation Systems, Components Thereof, and Products...
Federal Register 2010, 2011, 2012, 2013, 2014
...COMMISSION [Investigation No. 337-TA-657] Certain Automotive Multimedia Display and Navigation Systems, Components Thereof, and...the United States after importation of certain automotive multimedia display and navigation systems, components thereof,...
76 FR 38417 - In the Matter of Certain Multimedia Display and Navigation Devices and Systems, Components...
Federal Register 2010, 2011, 2012, 2013, 2014
...Investigation No. 337-TA-694] In the Matter of Certain Multimedia Display and Navigation Devices and Systems, Components Thereof...sale within the United States after importation of certain multimedia display and navigation devices and systems, components...
76 FR 25707 - In The Matter of Certain Multimedia Display and Navigation Devices and Systems, Components...
Federal Register 2010, 2011, 2012, 2013, 2014
...Investigation No. 337-TA-694] In The Matter of Certain Multimedia Display and Navigation Devices and Systems, Components Thereof...sale within the United States after importation of certain multimedia display and navigation devices and systems, components...
76 FR 22726 - Certain Multimedia Display and Navigation Devices and Systems, Components Thereof, and Products...
Federal Register 2010, 2011, 2012, 2013, 2014
...TRADE COMMISSION [Investigation No. 337-TA-694] Certain Multimedia Display and Navigation Devices and Systems, Components Thereof...sale within the United States after importation of certain multimedia display and navigation devices and systems, components...
11.09.2014 rrlab.cs.uni-kl.de Although precise GPS based localization systems are on the
Berns, Karsten
, these kind of RTK receivers usually fail in the forest as the GPS signal is shadowed by trees and vegetation11.09.2014 rrlab.cs.uni-kl.de Although precise GPS based localization systems are on the market. If a GPS signal is available, the localization accuracy is lower then 10m. If a robot should be able
Computer-assisted navigation system in intranasal surgery
NASA Astrophysics Data System (ADS)
Rapiejko, Piotr; Wojdas, Andrzej; Wawrzyniak, Zbigniew M.; Jurkiewicz, Dariusz
Due to anatomical variability and limited visibility of endoscopic image, endoscopic operations of nose and paranasal sinuses are ones of the most difficult surgical procedures. The field of operation often comprises anatomical structures, which often present anomalies. Computer-assisted navigational endoscopic surgery consists of routine tomography with the possibility of 3-axis projection allowing for localization of surgical instruments in proper relation to anatomic structures. This potential permits the surgeon to penetrate specific structures with surgical instruments and visualize their localization on computer tomography, which was earlier entered to the computer and projected. Projection of the images and endoscopic picture on the same monitor provides comfort to the operator and feeling of safety to the operated patient. The image analysis feature supplies a set of information necessary for safer and more effective procedure conduction and decreased number of complications. This technique may considerably contribute to training programs in endoscopic surgery. Computer-aided navigation in surgical procedures allows for precise biopsy specimen uptake for pathological examination, even in cases requiring precision up to 1 mm. The authors present an overview of surgical computer-aided navigation systems and their own experience in endoscopic ethmoid and maxillary sinus surgery performed with the use of computer-assisted navigation system.
In Proceedings 2010 Integrated Communications Navigation and Surveillance (ICNS) Conference, May 11-13, 2010 ANALYSIS OF PERFORMANCE OF Q ROUTES FOR ESTABLISHING
In Proceedings 2010 Integrated Communications Navigation and Surveillance (ICNS) Conference, May 11 Equipment (DME)/DME/IRU or /and Global Positioning System (GPS)/ Global Navigation Satellite Systems (GNSS 2010 Integrated Communications Navigation and Surveillance (ICNS) Conference, May 11-13, 2010
Fault Tolerant and Adaptive GPS Attitude Determination Alicia Morales-Reyes, Nakul Haridas, Ahmet T. Erdogan and Tughrul Arslan
Arslan, Tughrul
. INTRODUCTION The navigation system of air and space crafts is based on the Attitude Determination and Control1 Fault Tolerant and Adaptive GPS Attitude Determination System Alicia Morales-Reyes, Nakul Haridas platform for the GPS attitude determination is proposed. The algorithm encompasses speed, adaptability
Global Positioning System Primer
NSDL National Science Digital Library
The Global Positioning System (GPS) Primer, created by the Aerospace Corporation, gives basic information on how a GPS works and the many ways in which it is used. Supplying straight-forward text with a few graphics and illustrations, sections range from "What is Navigation?" to "Military Uses for GPS." Includes a search option and an organized selection of links to other GPS related sites. The GPS Primer is also downloadable (.pdf, 1618 KB).
Theoretical Description of a Bistatic System for Ocean Altimetry Using the GPS Signal
NASA Technical Reports Server (NTRS)
Hajj, G.; Zuffada, C.; Thomas, J.
The paper presents the fundamental characteristics of bistatic altimetry performed using the Global Positioning System (GPS) signal scattered off the ocean surface and collected by a receiver in space.
Algorithms for GPS operation indoors and downtown
Sahai, Anant
Algorithms for GPS operation indoors and downtown Nainesh Agarwal � Julien Basch � Paul Beckmann � for availability of GPS in urban and indoor environments. This de- mand calls for enhanced GPS algorithms that ac requirements for GPS. Unlike the military and vehicle navigation ap- plications of the past, to support
NSDL National Science Digital Library
Integrated Teaching and Learning Program,
During a scavenger hunt and an art project, students learn how to use a handheld GPS receiver for personal navigation. Teachers can request assistance from the Institute of Navigation to find nearby members with experience in using GPS and in locating receivers to use. Visit the ION website (www.ion.org) for links to local ION sections and member contact information. (Note: Mention of specific receiver manufacturers or brands does not constitute an endorsement by the Institute of Navigation or the University of Colorado.)
On-Board Perception System For Planetary Aerobot Balloon Navigation
NASA Technical Reports Server (NTRS)
Balaram, J.; Scheid, Robert E.; T. Salomon, Phil
NASA's Jet Propulsion Laboratory is implementing the Planetary Aerobot Testbed to develop the technology needed to operate a robotic balloon aero-vehicle (Aerobot). This earth-based system would be the precursor for aerobots designed to explore Venus, Mars, Titan and other gaseous planetary bodies. The on-board perception system allows the aerobot to localize itself and navigate on a planet using information derived from a variety of celestial, inertial, ground-imaging, ranging, and radiometric sensors.
Lichun SUI; Liqiu MENG
Some new methods for analyzing geo-referenced statistical data are presented in this paper. These methods have combined the techniques of exploratory data analysis with algorithms for data mining. They have been integrated in a prototype software system developed at the Technical University of Munich in cooperation with Navigation Technologies (NavTech) GmbH. The system serves the purpose of value-adding the road
GPS meteorology - Remote sensing of atmospheric water vapor using the Global Positioning System
NASA Technical Reports Server (NTRS)
Bevis, Michael; Businger, Steven; Herring, Thomas A.; Rocken, Christian; Anthes, Richard A.; Ware, Randolph H.
We present a new approach to remote sensing of water vapor based on the Global Positioning System (GPS). Geodesists and geophysicists have devised methods for estimating the extent to which signals propagating from GPS satellites to ground-based GPS receivers are delayed by atmospheric water vapor. This delay is parameterized in terms of a time-varying zenith wet delay (ZWD) which is retrieved by stochastic filtering of the GPS data. Given surface temperature and pressure readings at the GPS receiver, the retrieved ZWD can be transformed with very little additional uncertainty into an estimate of the integrated water vapor (IWV) overlying that receiver. Networks of continuously operating GPS receivers are being constructed by geodesists, geophysicists, and government and military agencies, in order to implement a wide range of positioning capabilities. These emerging GPS networks offer the possibility of observing the horizontal distribution of IWV or, equivalently, precipitate water with unprecedented coverage and a temporal resolution of the order of 10 min. These measurements could be utilized in operational weather forecasting and in fundamental research into atmospheric storm systems, the hydrologic cycle, atmospheric chemistry, and global climate change.
Real-time tracking management system using GPS, GPRS and Google earth
Noppadol Chadil; Apirak Russameesawang; Phongsak Keeratiwintakorn
Due to the high cost of fossil-based energy, several methods are proposed to reduce the usage of the energy in logistics and fleet management to be even more. GPS tracking system is a common approach to get vehicle location information in real-time for fleet planning. We proposed a GPS tracking system called Goo-Tracking that is composed of commodity hardware, open
Vehicle health management for guidance, navigation and control systems
NASA Technical Reports Server (NTRS)
Radke, Kathleen; Frazzini, Ron; Bursch, Paul; Wald, Jerry; Brown, Don
The objective of the program was to architect a vehicle health management (VHM) system for space systems avionics that assures system readiness for launch vehicles and for space-based dormant vehicles. The platforms which were studied and considered for application of VHM for guidance, navigation and control (GN&C) included the Advanced Manned Launch System (AMLS), the Horizontal Landing-20/Personnel Launch System (HL-20/PLS), the Assured Crew Return Vehicle (ACRV) and the Extended Duration Orbiter (EDO). This set was selected because dormancy and/or availability requirements are driving the designs of these future systems.
BeiDou Navigation Satellite System and its time scales
NASA Astrophysics Data System (ADS)
Han, Chunhao; Yang, Yuanxi; Cai, Zhiwu
The development and current status of BeiDou Navigation Satellite System are briefly introduced. The definition and realization of the system time scales are described in detail. The BeiDou system time (BDT) is an internal and continuous time scale without leap seconds. It is maintained by the time and frequency system of the master station. The frequency accuracy of BDT is superior to 2 � 10-14 and its stability is better than 6 � 10-15/30 days. The satellite synchronization is realized by a two-way time transfer between the uplink stations and the satellite. The measurement uncertainty of satellite clock offsets is less than 2 ns. The BeiDou System has three modes of time services: radio determination satellite service (RDSS) one-way, RDSS two-way and radio navigation satellite service (RNSS) one-way. The uncertainty of the one-way time service is designed to be less than 50 ns, and that of the two-way time service is less than 10 ns. Finally, some coordinate tactics of UTC from the viewpoint of global navigation satellite systems (GNSS) are discussed. It would be helpful to stop the leap second, from our viewpoint, but to keep the UTC name, the continuity and the coordinate function unchanged.
SIG Technology Review Summer 1994 57 Real-Time Navigation Using the Global Positioning System
Simon, Dan
SIG Technology Review � Summer 1994 57 Real-Time Navigation Using the Global Positioning System Real-Time Navigation Using the Global Positioning System Dan Simon and Hossny El-Sherief, TRW Ballistic Technology Review � Summer 1994 Real-Time Navigation Using the Global Positioning System introduces errors
Software engineering of a navigation and guidance system for commercial aircraft
NASA Technical Reports Server (NTRS)
Lachmann, S. G.; Mckinstry, R. G.
The avionics experimental configuration of the considered system is briefly reviewed, taking into account the concept of an advanced air traffic management system, flight critical and noncritical functions, and display system characteristics. Cockpit displays and the navigation computer are examined. Attention is given to the functions performed in the navigation computer, major programs in the navigation computer, and questions of software development.
Stanford University
by a skeletal network of radio-navigation aids. In the future National Airspace System of the United StatesDESIGN AND PERFORMANCE ANALYSIS OF A LOW-COST AIDED DEAD RECKONING NAVIGATION SYSTEM D. Gebre navigation system based on the fusion of inexpensive inertial, air data and magnetic sensors aided
A Navigation System for Robot Soccer Brett Browning, Gordon Wyeth and Ashley Tews
Browning, Brett
A Navigation System for Robot Soccer Brett Browning, Gordon Wyeth and Ashley Tews Computer Science describes the navigation system used for the UQ RoboRoos robot soccer team, runner up in the 1998 world RoboCup championships. The navigation system has been developed to cope with the dynamic environment of robot soccer
Pilot factors guidelines for the operational inspection of navigation systems
NASA Technical Reports Server (NTRS)
Sadler, J. F.; Boucek, G. P.
A computerized human engineered inspection technique is developed for use by FAA inspectors in evaluating the pilot factors aspects of aircraft navigation systems. The short title for this project is Nav Handbook. A menu-driven checklist, computer program and data base (Human Factors Design Criteria) were developed and merged to form a self-contained, portable, human factors inspection checklist tool for use in a laboratory or field setting. The automated checklist is tailored for general aviation navigation systems and can be expanded for use with other aircraft systems, transports or military aircraft. The Nav Handbook inspection concept was demonstrated using a lap-top computer and an Omega/VLF CDU. The program generates standardized inspection reports. Automated checklists for LORAN/C and R NAV were also developed. A Nav Handbook User's Guide is included.
Skip navigation Wireless System Tracks Esophageal Reflux
Chiao, Jung-Chih
better testing than catheters now used MedlinePlus: Wireless System Tracks Esophageal Reflux URL: http://www.nlm.nih.gov Esophageal Reflux URL: http://www.nlm.nih.gov/medlineplus/news/fullstory_51164.html #12;