TECHNICAL FIELD 
     The present invention generally relates to aircraft display systems and methods, and more particularly, to systems and methods for the enhanced display of waypoints. 
     BACKGROUND 
     Computer generated aircraft displays have become highly sophisticated and are capable of displaying a substantial amount of flight management, navigation and control information, which gives flight crews more effective control of their aircraft and helps to reduce their workload. In this regard, electronic displays, such as Heads-Up Displays (HUDs) and Heads-Down Displays (HDDs), are used in aircraft as Primary Flight Displays to display important flight management, navigation and control information to flight crews. 
     Primary Flight Displays are computer-generated displays that provide flight crews with real-time visual representations of the operational states of their aircraft during flights. For example, the Primary Flight Display can combine critical flight instrumentation (e.g., altitude, attitude, heading, airspeed, vertical speed instruments) and primary engine instrument indicators into a single, readily interpretable display. As a result, Primary Flight Displays have become effective visual tools for controlling aircraft, reducing pilot workload, increasing situational awareness, and improving overall flight safety. 
     Certain flight information displayed on Primary Flight Displays, particularly navigation information such as waypoints, is important for maintaining proper aircraft safety and control. However, other displayed symbology, such as the aircraft&#39;s current pitch, heading, flight path, and target information, may be displayed on or around the waypoints to clutter or obscure these portions of the Primary Flight Display. This is particularly an issue when the aircraft is at a relatively great distance from the waypoints. 
     Accordingly, it is desirable to provide systems and methods that increase the visibility of certain flight information on a visual display, such as, for example, a Primary Flight Display, similar electronic aircraft displays, and other types of electronic displays. Particularly, it is desirable to provide systems and methods for increasing the visibility of waypoints on the display. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention. 
     BRIEF SUMMARY 
     In accordance with one exemplary embodiment, a display system for a vehicle is provided. The display system includes a processor configured to receive data representative of a waypoint and terrain and to supply display commands associated with the waypoint and the terrain; and a display device coupled the processor for receiving the display commands and operable to render three-dimensional terrain and a first symbol elevated from the terrain representing the waypoint. 
     In accordance with another exemplary embodiment, a method is provided for displaying a waypoint on terrain within a three-dimensional visual display of a vehicle. The method includes determining a distance of the waypoint from the vehicle; and displaying a symbol representing the waypoint on the terrain as a function of the distance. 
     In accordance with yet another exemplary embodiment, a display system for a vehicle is provided. The display system includes a processor configured to receive data representative of a waypoint and terrain and to supply display commands associated with the waypoint and the terrain; and a display device coupled the processor for receiving the display commands and operable to render three-dimensional terrain and a first symbol representing the waypoint elevated from the terrain and anchored to the terrain. The first symbol is replaced by a second symbol representing the waypoint when the vehicle approaches the waypoint, the second symbol conforming to the terrain. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein: 
         FIG. 1  is a functional block diagram of a display system according to an exemplary embodiment; 
         FIG. 2  depicts an exemplary image that may be rendered by the system of  FIG. 1 ; and 
         FIG. 3  depicts another exemplary image that may be rendered by the system of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description. 
     Broadly, exemplary embodiments described herein are provided for increasing the visibility of waypoints on electronic displays, such as, for example, Primary Flight Displays, similar types of visual displays, or electronic displays for other types of vehicles. More specifically, waypoints can appear elevated from the terrain at certain distances from the aircraft, and conform to the terrain as the aircraft approaches the waypoint. 
       FIG. 1  depicts a block diagram of an exemplary display system  100  for increasing the visibility of waypoints on a visual display. The system  100  includes a processing unit  102 , a database  104 , a flight management system  106 , a navigation system  108 , a graphics display generator  110 , and a visual display  112 . Notably, it should be understood that although the system  100  appears in  FIG. 1  to be arranged as an integrated system, the system  100  is not so limited and can also include an arrangement whereby one or more of the processing unit  102 , the database  104 , the flight management system  106 , the navigation system  108 , the graphics display generator  110 , and the visual display  112  is a separate component or a subcomponent of another system located either onboard or external to an aircraft. Also, for example, the system  100  can be arranged as an integrated system (e.g., aircraft display system, Primary Flight Display system, etc.) or a subsystem of a more comprehensive aircraft system (e.g., flight management system, navigation and control system, target aiming and control system, collision alert and/or avoidance system, weather avoidance system, etc.). The system  100  can be utilized in an aircraft, such as a helicopter, airplane, or unmanned vehicle. Moreover, exemplary embodiments of the system  100  can also be utilized in spacecraft, ships, submarines, or other types of vehicles. For simplicity, embodiments are described below with reference to “aircraft.” 
     For this embodiment, the processing unit  102  can be a computer processor such as, for example, a microprocessor, digital signal processor, or any suitable processor capable of at least receiving and/or retrieving aircraft flight management information (e.g., from the flight management system  106 ), navigation and control information (e.g., from the navigation system  108 ), and target and/or terrain information (e.g., from the database  104 ); generating display control signals for a visual display of the aircraft flight management information, the navigation and control information (including, for example, a zero pitch reference line, one or more heading indicators, tapes for airspeed and altitude, etc.), target, waypoint, and/or terrain information, and a flight path marker (or similar type of aircraft aiming symbol); and sending the generated display control signals to a graphics display generator (e.g., the graphics display generator  110 ) associated with a visual display (e.g., the visual display  112 ). 
     The database  104  is coupled to the processor  102  and can be a memory device (e.g., non-volatile memory, disk, drive, tape, optical storage device, mass storage device, etc.) that can store digital waypoint and target location data and terrain data (e.g., latitudinal and longitudinal data) as either absolute coordinate data or as a function of an aircraft&#39;s position. The database  104  includes data defining the actual geographical boundaries of numerous airports and runways. The database  104  can also include, for example, a terrain database, which can include the locations and elevations of natural terrain obstacles such as mountains or other elevated ground areas, and also the locations and elevations of man-made obstacles such as radio antenna towers, buildings, bridges, etc. Navigation data stored in the database  104  can be received from external, up-linked sources, or an onboard device that senses and maps man-made obstacles (e.g., airports, runways, etc.) and variations in terrain, such as, for example, a Forward Looking Infrared (FLIR) sensor, or an active or passive type of radar device. 
     The flight management system  106  and the navigation system  108  are coupled to processing unit  102 . The flight management system  106  and/or the navigation system  108  can provide navigation data associated with the aircraft&#39;s current position and flight direction (e.g., heading, course, track, etc.) to the processing unit  102 . The navigation data provided to the processing unit  102  can also include information about the aircraft&#39;s airspeed, altitude, pitch, and other important flight information, if such information is desired. In any event, for this exemplary embodiment, the flight management system  106  and/or the navigation system  108  can include any suitable position and direction determination devices that are capable of providing the processing unit  102  with at least an aircraft&#39;s current position (e.g., in latitudinal and longitudinal form), the real-time direction (heading, course, track, etc.) of the aircraft in its flight path, the waypoints along the flight path, and other important flight information (e.g., pitch, airspeed, altitude, attitude, etc.). Information can be provided to the processing unit  102  by, for example, an Inertial Reference System (IRS), Air-data Heading Reference System (AHRS), and/or a global positioning system (GPS). 
     For this embodiment, the system  100  also includes the graphics display generator  110  coupled to the processing unit  102  and the visual display  112 . The visual display  112  may include any device or apparatus suitable for displaying various types of computer generated symbols and information representing at least pitch, heading, flight path, airspeed, altitude, waypoints, targets, terrain and flight path marker data in an integrated, multi-color or monochrome form. Using data retrieved (or received) from the flight management system  106  and/or the navigation system  108 , the processing unit  102  executes one or more algorithms (e.g., implemented in software) for determining the position of waypoints, a flight path marker, a zero pitch reference line, and heading indicators on the visual display  112 . The processing unit  102  then generates a plurality of display control signals representing the waypoints, flight path marker, zero pitch reference line, heading indicators, and airspeed and altitude tapes (along with target and terrain data from the database  104 ), and sends the plurality of display control signals to the visual display  112  via the graphics display generator  110 . In this embodiment, the visual display  112  is an aircraft cockpit, multi-color display (e.g., a Primary Flight Display). The graphics display generator  110  interprets the display control signals and generates suitable waypoints, flight path marker, zero pitch reference line, heading indicator, airspeed tape, altitude tape, target, and terrain symbols, which are presented on a screen or monitor of the visual display  112 . 
     Although a cockpit display screen may be used to display the above-described flight information symbols and data, any suitable type of display medium capable of visually presenting multi-colored or monochrome flight information for a pilot or other flight crew member can be provided, such as, for example, various CRT and flat-panel display systems (e.g., CRT displays, LCDs, OLED displays, plasma displays, projection displays, HDDs, HUDs, etc.). 
       FIG. 2  depicts an exemplary visual display  200  that may be rendered by the flight deck display system  100  of  FIG. 1 . The display  200  shows, among other things, computer generated symbols representing a zero pitch reference line (e.g., commonly referred to as a horizon line)  202 , two heading indicators  204 , a flight path marker (also known as a flight path vector or velocity vector)  206 , an airspeed scale or tape  210 , an altitude scale or tape  212 , and terrain (e.g., identified generally as element  214 ). In this embodiment, the terrain  214  is rendered as a three-dimensional, perspective view. The terrain  214  can include any representation of the environment surrounding the aircraft, including flattened terrain. Additionally, the terrain  214  can include a virtual plane selected by a pilot at certain elevation relative to the aircraft and is rendered at that elevation. Although the display  200  is shown as an egocentric, first-person frame of reference, the display  200  can be a secondary, wingman, and/or plan or perspective view that enables a viewer to view the aircraft, as well as zoom in and out. 
     In addition, and as will now be described in more detail, the display  200  may also selectively render information representative of one or more waypoints  250 ,  260 . The waypoints  250 ,  260  may be any intended destination or other type of geo-referenced symbol along a flight path. During operation, the pilot typically locates the waypoints  250 ,  260  on the display  200 , and aims the aircraft in the direction of the waypoint  250 ,  260 . The location and placement of the waypoints  250 ,  260  can be identified from a flight plan, user selected from the database  104  ( FIG. 1 ), provided by a user via one or more of the user interfaces (e.g., keyboard, CCD, voice control, mind responsive device), or provided or selected from the external data sources, for example, with a datalink to the cockpit from the ground. 
       FIG. 2  shows two waypoints  250 ,  260  that are to be sequentially navigated and that are a predetermined distance from the aircraft. The waypoint  250  is the closer waypoint, and the waypoint  260  is the more distant waypoint. The representation of waypoints  250 ,  260  may be a function of the distance of the waypoints  250 ,  260  from the aircraft. As will be described in further detail below, the waypoints  250 ,  260  can be modified as the aircraft approaches. 
     The waypoints  250 ,  260  are sized and shaped to increase visibility, particularly at relatively large distances. In this embodiment, each of the waypoints  250 ,  260  has an elevated portion  252 ,  262  that is elevated relative to the terrain  214 , and in this case, is star-shaped. Each of the elevated portions  252 ,  262  may further include a line  254 ,  264  that is anchored to terrain  214 . Generally, the elevated portions  252 ,  262  of the waypoints  250 ,  260  are displayed in a scale that is larger than the terrain  214 . In other words, the waypoints  250 ,  260  have larger symbolic representations that those in most conventional displays to provide increased visibility. The size and color of the waypoints  250 ,  260  can also vary as a function of distance from the aircraft, and can, for example, become smaller or change color as the aircraft gets closer. The elevated nature and dynamic size and color of the waypoints  250 ,  260  increases visibility and awareness, without otherwise cluttering the display  200 . Although the elevated portion  252 ,  262  of the waypoint  250 ,  260  is star-shaped, other shapes, such as circular, rectangular, trapezoidal or other shapes, can be provided. The waypoints  250 ,  260  can have the same or different colors. In one embodiment, the waypoints  250 ,  260  have different colors that indicate their sequential navigation order. The waypoints  250 ,  260  can also vary as a function of use conditions. As an example, the waypoint  250  is a final approach fix at which point the aircraft must attain certain speed and altitude combination to land safely. The waypoint  250 ,  260  can be accordingly colored or shaped or associated with certain textual information to indicate such conditions. Similarly, each waypoint  250 ,  260  may have an airspeed associated with it. The specific symbology and/or appearance of the waypoint  250 ,  260  may be sensitive to the aircraft&#39;s energy state and communicate that information to the flight crew. 
       FIG. 3  depicts another exemplary image that may be rendered by the system  100  of  FIG. 1 . Generally,  FIG. 3  is similar to  FIG. 2 , except that the aircraft is at a closer distance to the waypoints  250 ,  260 . In contrast to  FIG. 2 , the waypoints  250 ,  260  are no longer elevated. In this embodiment, as the aircraft approaches the waypoints  250 ,  260 , the waypoints  250 ,  260  conform to the terrain  214 . By tracing the terrain  214 , the waypoints  250 ,  260  are not obscured by the three-dimensional nature of the terrain  214 . Typically this may occur when waypoint is less than several miles ahead or when waypoint presentation may obscure other information such as direct path to a landing target. The waypoints  250 ,  260  of  FIG. 3  can have the same or different shape from the waypoints  250 ,  260  of  FIG. 2 . 
     In this embodiment, each of waypoints  250 ,  260  has an approach or flight path for navigating the aircraft to the waypoints  250 ,  260 . If the aircraft deviates from the approach, the waypoints  250 ,  260  can change color to alert the pilot. Additionally, the waypoints  250 ,  260  can fade-out or become more transparent as the aircraft approaches. This can decrease the clutter on the visual display as the pilot attempts to navigate past the waypoints  250 ,  260 . Other important flight information, such as, for example, airspeed and altitude readings, and underlying terrain and target information, are not obscured by the waypoints  250 ,  260 . The waypoint  250 ,  260  may fade in and out may be controlled by the distance to the waypoint  250 ,  260  or by the time the aircraft will reach the waypoint  250 ,  260 . Therefore, the dynamic control of the appearance of the waypoints  250 ,  260  enables increased visibility of the waypoints  250 ,  260  while enabling other flight information symbology to be displayed, thereby reducing pilot workload and navigation and control errors, and increasing flight safety. In an alternate embodiment, the waypoints  250 ,  260  of  FIG. 3  have the same shape and appearance as the waypoints  250 ,  260  in  FIG. 2 , although larger due to the closer proximity. In other words, the waypoints  250 ,  260  as the aircraft approaches can remain elevated relative to the terrain and anchored. 
     While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the invention. It being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims.
A display system and method for a vehicle are provided. The display system includes a processor configured to receive data representative of a waypoint and terrain and to supply display commands associated with the waypoint and the terrain; and a display device coupled the processor for receiving the display commands and operable to render three-dimensional terrain and a first symbol elevated from the terrain representing the waypoint.