Abstract:
A display system for a vehicle includes a sensor system configured to collect first terrain data; a database configured to store second terrain data; a processing unit coupled to the sensor system and database, the processing unit configured to receive the first and second terrain data, to integrate the first and second terrain data into a common three-dimensional view that comprises symbology representing both the first and second terrain data, and to supply display commands associated with the first and second terrain data; and a display device coupled the processing unit and configured to receive the display commands and operable to render the common three-dimensional view to thereby allow simultaneous viewing of the first and second terrain data.

Description:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     This invention was made with U.S. Government support under Agreement No. W31P4Q-07-C-0182 awarded pursuant to the DARPA/Sandblaster Program. The U.S. Government may have certain rights in this invention. 
    
    
     TECHNICAL FIELD 
     The present invention generally relates to aircraft display systems and methods and, more particularly, to systems and methods that display images representing terrain data integrated from database and sensor sources. 
     BACKGROUND 
     Computer generated aircraft displays have become highly sophisticated and capable of displaying a substantial amount of flight management, navigation, and control information that gives flight crews more effective control of the aircraft and a reduction in 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. 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. 
     Some Primary Flight Displays may provide a 3D, synthetic perspective view of the terrain surrounding the aircraft, including man-made and natural terrain. These images are typically based on pre-loaded and predetermined terrain data from a database. In some situations, the terrain data from the database may need to be updated over time, particularly when the terrain data relates to man-made obstacles such as buildings and movable vehicles. 
     Accordingly, it is desirable to provide systems and methods that increase the accuracy of terrain data displayed 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 that display images of the terrain based on integrated data from both database and sensor sources. 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 an exemplary embodiment, a display system for a vehicle is provided. The display system includes a sensor system configured to collect first terrain data; a database configured to store second terrain data; a processing unit coupled to the sensor system and database, the processing unit configured to receive the first and second terrain data, to integrate the first and second terrain data into a common three-dimensional view that comprises symbology representing both the first and second terrain data, and to supply display commands associated with the first and second terrain data; and a display device coupled the processing unit and configured to receive the display commands and operable to render the common three-dimensional view to thereby allow simultaneous viewing of the first and second terrain data. 
     In another exemplary embodiment, a method is provided for displaying first terrain data from a sensor system and second terrain data from a database. The method includes receiving the first terrain data from the sensor system; receiving the second terrain data from the database; evaluating an integrity of the first and second terrain data; prioritizing the first and second terrain data based on the integrity evaluation to create a prioritized result; blending the first and second terrain data based on the prioritized result to create blended first and second terrain data; and producing display signals based on the blended first and second terrain data. 
     In yet another exemplary embodiment, a Primary Flight Display system for an aircraft is provided. The Primary Flight Display includes a sensor system configured to collect first terrain data; a database configured to store second terrain data; a processing unit coupled to the sensor system and database, the processing unit configured to receive, blend, evaluate, and prioritize the first and second terrain data into a common three-dimensional view that comprises symbology representing both the first and second terrain data, and to supply display commands associated with the first and second terrain data; and a display device coupled the processing unit and configured to receive the display commands and operable to render the common three-dimensional view to thereby allow simultaneous viewing of the first and second terrain data, including symbology representing the first terrain data in a first color and the second terrain data in a second color. 
    
    
     
       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 an aircraft display system according to an exemplary embodiment; 
         FIG. 2  is a flowchart describing a method for displaying images representing integrated database and sensor data in accordance with an exemplary embodiment; and 
         FIG. 3  depicts an exemplary image that may be rendered by the aircraft display 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 provide visual display systems and methods for aircraft. More specifically, the visual display systems and methods that display images of terrain data integrated form both database and sensor sources. 
       FIG. 1  depicts a block diagram of an exemplary aircraft visual display system  100  for displaying images representing integrated database and sensor data. In the exemplary embodiment shown, the system  100  includes a processing unit  102 , a database  104 , a flight management system  106 , a display device  108 , and sensor system  110 . 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 display device  108 , and the sensor system  110  are separate components or subcomponents 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, a Head Up Display with SVS or EVS as an overlay, a “near to eye display” system, or a head mounted 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, fixed wing and rotor aircraft, such as helicopters, as well as other types of vehicles. For simplicity, embodiments are described below with reference to “aircraft.” 
     The processing unit  102  can be a computer processor associated with a Primary Flight Display. Generally, the processing unit  102  receives and/or retrieves flight management information (e.g., from the flight management system  106 ) and landing, target and/or terrain information (e.g., from database  104  or sensor system  110 ). The processing unit  102  generates display control signals for a visual display of the flight management information, which includes navigation and control symbology such as a zero pitch reference line, heading indicators, tapes for airspeed and altitude, flight path information, RNP information, and any other information desired by a flight crew. As discussed in further detail below, the processing unit  102  additionally receives and integrates terrain data from the database  104  and sensor system  110 , and generates display control signals based on the integrated terrain data. The processing unit  102  then sends the generated display control signals to a display device (e.g., the display device  108 ). More specific functions of the processing unit  102  will be discussed below. 
     Database  104  is coupled to processing unit  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 landing, waypoint, and target location as either absolute coordinate data or as a function of an aircraft&#39;s position. Database  104  can additionally include other types of navigation information, such as information used to calculate flight path and determine RNP information. Database  104  can also include, for example, a terrain database, which includes the locations and elevations of natural and man-made terrain. The terrain can include obstacles, such as buildings and vehicles. Obstacle data can be stored together with terrain database or in a separated obstacle only database. The geographic locations and height of the obstacles for typical avionics applications can be obtained through survey or through various reporting services. 
     The sensor system  110  is coupled to the processing unit  102  and can include any suitable sensor for detecting terrain and providing data to the processing unit  102  based on the detected terrain. The sensor system  110  can include sensors such as radar or forward-looking infrared (FLIR). Other types of imaging sensors may include types such as visible light, millimeter-wave radar, X-band (weather) radar, etc. In one embodiment, the sensor system  110  is a stand-alone system, although in other embodiments, the sensor system  110  can be used to completely or partially verify database  104 . The sensor collected data, after additional verifications, may be later inserted into the database  104  for future uses. 
     The flight management system  106  is coupled to processing unit  102 , and 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. In exemplary embodiments, the flight management system  106  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.). Such 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). 
     The system  100  also includes the display device  108  coupled to the processing unit  102 . The display device  108  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, landing information, waypoints, targets, obstacle, terrain, and RNP data in an integrated, multi-color or monochrome form. Using data retrieved (or received) from the flight management system  106 , the processing unit  102  executes one or more algorithms (e.g., implemented in software) for determining the position of the various types of desired information on the display device  108 . The processing unit  102  then generates a plurality of display control signals representing this data, and sends display control signals to the display device  108 . The display device  108  and/or processing unit  102  may include a graphics display generator for generating the appropriate symbology on the screen of the display device  108 , as discussed in greater detail below. In this embodiment, the display device  108  is an aircraft cockpit, multi-color display (e.g., a Primary Flight Display). 
     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  is a flow chart that depicts a method  200  for displaying integrated sensor terrain data and database terrain data. In one embodiment, the method  200  is used for displaying terrain data in 3D, synthetic view for a Primary Flight Display of an aircraft, such as for example, the system  100  discussed above. As such, the method  200  of  FIG. 2  will be described with reference to  FIG. 1 . 
     In a first step  205 , the processing unit  102  receives sensor data related to the man-made and natural terrain surrounding the aircraft from sensor system  110 . In a second step  210 , the processing unit  102  receives database data related to the man-made and natural terrain surrounding the aircraft from database  104 . 
     In a third step  215 , the processing unit  102  evaluates the integrity of the sensor data and database data. The integrity can be based on a number of factors, including the health status and functionality of the sensor system  110  and/or database  104 . Other factors include the completeness of the data and the resolution of the data. Built In Test (BIT) requirements, for example, may be used to determine data integrity. If terrain sensors are degraded due to various reasons, database data may have higher integrity for the areas in which the two data sources overlap. The processing unit  102  will select higher integrity data source for the display. Among factors may can causes sensor integrity degradation are signal to noise performance degradation, the presence of significant interferences, or mounting fixture malfunctions. 
     In a fourth step  220 , the processing unit  102  prioritizes the sensor data and database data based on the evaluation in step  215 . The processing unit  102  will generally have a set of rules to determine the priority of the data to be displayed. For example, if the sensor data is evaluated to meet a predetermined threshold of integrity, the sensor data is prioritized over the database data. Typically, the sensor data is more accurate than the database data because it may be more up-to-date. Additionally, the prioritization may be based on a location of interest. If a location is particularly important to a pilot and the integrity evaluation for both the sensor data and database data are relatively close, the processing unit  102  will generally choose the sensor data to be displayed in the location of interest. As noted above, the sensor data is typically more up-to-date and accurate. Additional considerations for prioritization may include the mobility of the subject of the data. In one embodiment, terrain data retrieved from the sensor system  110  can include moveable terrain, such as buildings, and mobile structures and systems. Sensor data is more suitable for this type of terrain data. As another example, data related to waterbody information and geopolitical boundaries can be designated to come from database  104 . In some instances, certain objects may be detected by the sensor system  100 , but the object may be known from the database  104 . In these cases, it may save processing resources to use data from the database  104 . 
     In a fifth step  225 , the processing unit  102  blends the sensor data and database data based on the evaluation and prioritization steps  215 - 220 . In this step, the processing unit  102  will also evaluate the blended data to ensure that a continuous synthetic view can be achieved. If there are gaps or “holes” in the field of view, the processing unit  102  may interpolate between known data points to provide a continuous view. The interpolation of the sensor data may be performed by choosing the average values of the sensor data around the gap area or interpolate with certain smooth functions such as linear relations. This is to assume that the data around that area should not exhibit significant variations since large variations can be generally detected. 
     In a sixth step  230 , the processing unit  102  generates display signals based on the sensor data and/or database data and provides the display signals to the display device  108 . An exemplary visual display  300  is shown in  FIG. 3 . The visual display  300  is an exemplary visual display that may be rendered, for example, by the aircraft display system  100  of  FIG. 1 . 
     The visual display  300  shows, among other things, computer generated symbols representing a zero pitch reference line (e.g., commonly referred to as a horizon line)  302 , an airspeed scale or tape  304 , an altitude scale or tape  306 , a landing point  308 , and terrain (e.g., identified generally as element  310 ). Although the visual display  300  is shown as an egocentric, first-person frame of reference, the visual display  300  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, including an unmanned vehicle and/or spacecraft. Although the visual display  300  is generally associated with a Primary Flight Display, the display can also be utilized on a multi-function display, Head Up Display, and/or a head mounted display. 
     In this embodiment, the terrain  310  is rendered as a three-dimensional, perspective view. The terrain  310  can include any representation of the environment surrounding the aircraft, including flattened terrain. Additionally, the terrain  310  can include a virtual plane selected by a pilot at certain elevation relative to the aircraft and is rendered at that elevation. 
     In addition, and as will now be described in more detail, the visual display  300  may selectively render symbology forming part of the terrain  310  that represents terrain data from the sensor system  110  and terrain data from the database  104 . One exemplary process  200  is described above in reference to  FIG. 2  to illustrate how the terrain data from the sensor system  110  and the terrain data from the database  104  are blended and displayed. In one exemplary embodiment, the visual display  300  indicates the particular source of the terrain data to the flight crew. For example, first portions  320  of terrain  310  are rendered in a first, darker color, and second portions  330  of terrain  310  are rendered in a second, lighter color. The first portions  320  represent terrain  310  based on terrain data from the sensor system  110 , and the second portions  330  represent terrain  310  based on terrain data from the database  104 . As such, the different colors provide the flight crew an easily identifiable indication of the source of terrain data. In further embodiments, the first and second portions  320 ,  330  may be the same color, but have different textures, appearances, attributes or other types of differentiating indications. 
     A third portion  340  is rendered in a third, even darker color. The third portion  340  can represent data that has been interpolated from the surrounding data, which in this case, is data from the sensor system  110 . A boundary  350  can be additionally provided to more clearly delineate between the first, second and third portions  320 ,  330 ,  340 . 
     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.