Abstract:
A visual display system for an aircraft is provided. The system includes a database for storing obstacle information and a processor coupled to the database and configured to construct an obstacle warning envelope for the aircraft and receive obstacle information from the database based on the obstacle warning envelope. The processor is further configured to supply display commands associated with the obstacle warning envelope and the obstacle information. The system further includes a display device coupled the processor for receiving the display commands and operable to render a three-dimensional view, including the obstacle warning envelope and the obstacle. The display device provides a warning when the obstacle is within the obstacle warning envelope.

Description:
TECHNICAL FIELD 
       [0001]    The present invention generally relates to aircraft display systems and methods and, more particularly, to aircraft systems and methods for enhanced display of obstacles. 
       BACKGROUND 
       [0002]    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. 
         [0003]    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. 
         [0004]    Flight information regarding obstacles displayed on Primary Flight Displays is useful in maintaining proper aircraft safety and control. Information about obstacles in or near the flight path is particularly important, especially to aircraft flying at low altitudes, such as during landing, take off, or low visibility conditions. Conventional display systems, including those with ground proximity warning systems, may exhibit challenges in providing an accurate perception of aircraft distance to an obstacle or, for example, the likelihood that the obstacle will pose an issue. Generally, the flight crew identifies and evaluates each obstacle to determine whether each obstacle will present an issue. This may require the flight crew to track the lateral and vertical distance from the obstacle, which may require the monitoring of flight critical data such as flight path, altitudes, and speed to ensure that the aircraft clears the obstacle. 
         [0005]    Accordingly, it is desirable to provide systems and methods that increase the visibility of obstacles that may impact the aircraft. 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 
       [0006]    In accordance with an exemplary embodiment, a visual display system for an aircraft is provided. The system includes a database for storing obstacle information and a processor coupled to the database and configured to construct an obstacle warning envelope for the aircraft and receive obstacle information from the database based on the obstacle warning envelope. The processor is further configured to supply display commands associated with the obstacle warning envelope and the obstacle information. The system further includes a display device coupled the processor for receiving the display commands and operable to render a three-dimensional view, including the obstacle warning envelope and the obstacle. The display device provides a warning when the obstacle is within the obstacle warning envelope. 
         [0007]    In accordance with another exemplary embodiment, a method of displaying an obstacle on an aircraft display system is provided. The method includes constructing and displaying an obstacle warning envelope; evaluating the obstacle relative to the obstacle warning envelope; and providing a warning if the obstacle is within the obstacle warning envelope. 
         [0008]    In accordance with yet another exemplary embodiment, a visual display system for an aircraft includes a database for storing obstacle information and a processor coupled to the database and configured to construct an obstacle warning envelope for the aircraft based on aircraft specific parameters, including a flight path of the aircraft, and receive obstacle information from the database based on the obstacle warning envelope. The processor is further configured to supply display commands associated with the obstacle warning envelope and the obstacle information, and to evaluate the obstacle within the obstacle warning envelope and determine a warning level of the warning. A display device is coupled the processor for receiving the display commands and operable to render a three-dimensional view, including the obstacle warning envelope and the obstacle. The display device provides a warning when the obstacle is within the obstacle warning envelope. The display device is configured to display a first warning at a first warning level when the obstacle is at a first distance from the aircraft and a second warning at a second warning level when the obstacle is at a second distance from the aircraft. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein: 
           [0010]      FIG. 1  is a functional block diagram of an aircraft display system according to an exemplary embodiment; 
           [0011]      FIG. 2  depicts an exemplary image that may be rendered by the aircraft display system of  FIG. 1 ; 
           [0012]      FIG. 3  depicts another exemplary image that may be rendered by the aircraft display system of  FIG. 1 ; and 
           [0013]      FIG. 4  depicts yet another exemplary image that may be rendered by the aircraft display system of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    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. 
         [0015]    Broadly, exemplary embodiments described herein provide visual display systems and methods for aircraft. More specifically, the visual display systems and methods display images that each include an obstacle warning envelope that provides warnings for obstacles that may impact the aircraft. 
         [0016]      FIG. 1  depicts a block diagram of an exemplary aircraft visual display system  100  for displaying an obstacle warning envelope that indicates warnings for obstacles that may impact the aircraft. The system  100  includes a processing unit  102 , a database  104 , a flight management system  106 , 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 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, 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.” 
         [0017]    The processing unit  102  can be a computer processor associated with a primary flight display (PFD), and/or a ground proximity warning system (GPWS), including an enhanced ground proximity warning system (EGPWS), terrain awareness and warning system (TAWS), and/or traffic collision avoidance system (TCAS). 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 ); generates display control signals for a visual display of the flight management information (including, for example, a zero pitch reference line, one or more heading indicators, tapes for airspeed and altitude, etc.), target, obstacle, and/or terrain information, and a flight path marker (or similar type of aircraft aiming symbol); and sends 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 ). More specific functions of the processing unit  102  will be discussed below. 
         [0018]    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 also include, for example, a terrain database, which includes the locations and elevations of natural terrain. More specifically, as discussed in further detail below, database  104  includes information concerning obstacles, including terrain obstacles such as mountains or other elevated ground areas, and also the locations and elevations of man-made obstacles such as smokestacks, radio antenna towers, buildings, bridges, etc. The obstacle information can include the type of obstacle, as well as height, latitudinal and longitudinal data. Obstacles of the foregoing type are generally depicted in various aeronautical publications (including, for example, the terminal area chart (TAC), sectional aeronautical chart (SAC) and world aeronautical chart (WAC)) and may also be represented in a variety of commonly available navigational databases that may be accessed either on the aircraft or on the ground. Navigation data stored in 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.). Obstacle information can also be obtained in real time with sensors, such as, for example, a Forward Looking Infrared (FLIR) sensor, or an active or passive type of radar device. 
         [0019]    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 one exemplary embodiment, 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, other important flight information (e.g., pitch, airspeed, altitude, attitude, etc.), and particularly obstacle information. 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). 
         [0020]    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, landing information, waypoints, targets, obstacle, terrain, and obstacle warning envelope 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 waypoints, obstacles, obstacle warning envelope, flight path marker, landing information, 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 this data, and sends 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 a suitable display, which is presented on a screen or monitor of the visual display  112 , as discussed in greater detail below. 
         [0021]    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.). 
         [0022]      FIGS. 2-4  depict examples of an exemplary visual display  200  that may be rendered by the aircraft 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 , 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. 
         [0023]    In addition, and as will now be described in more detail, the display  200  may also selectively render symbology representing an obstacle warning envelope  250  that functions to warn the flight crew of any obstacles (e.g., obstacle  260 ). Reference is additionally made to  FIG. 1  to describe the construction and function of the obstacle warning envelope  250 . 
         [0024]    The processing unit  102  constructs the obstacle warning envelope  250  with algorithms based on a number of parameters, including the present position of the aircraft, flight path, aircraft speed, wing span, altitude, pitch angle, roll angle, wind shear, ability of the aircraft to pull up, and the like. Generally, the obstacle warning envelope  250  is superimposed on the terrain  214  and provides an indication of the intended flight path of the aircraft such that problematic obstacles can be identified. The obstacle warning envelope  250  extends to a predetermined forward distance and includes a lateral margin of safety on either side of the aircraft. As one example, at greater speeds, the obstacle warning envelope  250  may extend to a greater distance than otherwise because the obstacles may affect the aircraft at shorter time intervals. Similarly, at greater aircraft weights, the obstacle warning envelope  250  may extend to a greater distance than otherwise because it takes more time for the aircraft to change position and direction. The obstacle warning envelope  250  may also extend beneath the aircraft with some safe margin of clearance. 
         [0025]    Database  104  includes data concerning obstacles (e.g., obstacle  260 ) within or near the obstacle warning envelope  250 , including manmade and natural structures. This data may include, for example, the position and altitude of each obstacle  260 . At each aircraft movement or at predetermined intervals, the processing unit  102  will recalculate the obstacle warning envelope  250  and evaluate the obstacle  260 . As discussed below, when the obstacle  260  approaches or is within the obstacle warning envelope  250 , i.e., when the obstacle  260  may pose a threat to the aircraft based on the flight plan and other aircraft specific parameters, the system  100  will provide a warning to the flight crew. Typically, the warning is based both on the position of the obstacle relative to the obstacle warning envelope  250  and the aircraft itself, as well as the height of the obstacle  260 , to ensure that the aircraft can fly over or around the obstacle  260 . 
         [0026]    As an example, in  FIG. 2 , the processing unit  102  constructs the obstacle warning envelope  250 , and searches database  104  for any obstacle that may fall within the obstacle warning envelope  250 . In this case, the obstacle  260  is outside of the obstacle warning envelope  250 . As a result, the system  100  will not provide any warning to the flight crew. Since no warning is necessary, the obstacle warning envelope  250  can be a default color such as green. As the aircraft moves or as the flight parameters change, the system  100  will continue to evaluate the obstacle  260  to determine whether a warning is necessary. 
         [0027]    In  FIG. 3 , the obstacle  260  falls within the obstacle warning envelope  250 . The processing unit  102  evaluates the obstacle  260  to determine the appropriate warning. In this case, the obstacle  260  is still some distance from the aircraft. As a result, the system  100  will issue an advisory warning. In this exemplary embodiment, the advisory warning can include changing the color of the obstacle warning envelope  250  and/or the obstacle  260 . In one example, the obstacle warning envelope  250  turns from green to amber. Additionally or as an alternative, the advisory warning can include pulsing the obstacle warning envelope  250  and/or obstacle  260  such that they blink. A dedicated warning annunciation  270  such as “OBST_ALERT” may also be provided.  FIG. 3  additionally depicts that the obstacle warning envelope  250  can generally track the intended flight path to give the flight crew a better indication of the obstacles  260  within the flight path. Conventional systems may only warn the flight crew about obstacles directly in front of the aircraft. As suggested above, the system  100  will continue to construct the obstacle warning envelope  250 , adjusting as necessary, and to evaluate the obstacle  260 . If the obstacle  260  moves outside of the obstacle warning envelope  250 , the warning indications will be removed. 
         [0028]    In  FIG. 4 , the obstacle  260  falls within the obstacle warning envelope  250  at a relatively close distance and at a height that may affect the aircraft. In this case, the system  100  will issue an alert warning that is more urgent than the advisory warning. In this exemplary embodiment, the alert warning can include changing the color of the obstacle warning envelope  250  and/or the obstacle  260  to red and causing one or both of them to blink. Additionally, an aural warning may be provided in the advisory and/or alert warnings. In a further embodiment, the system  100  can provide suggestions for avoiding the obstacle  260 , such as an alternate heading and/or a more urgent “pull-up” or “turn left” signal. The system  100  can render the obstacle warning envelope  250  at all times, or only at specified times, such as when the aircraft is below a certain altitude. 
         [0029]    Accordingly, exemplary embodiments discussed herein provide a visual display system  100  with an obstacle warning envelope  250  that alerts the flight crew to any obstacles  260  in the path of the aircraft. The system  100  automatically assesses each obstacle  260  and provides the appropriate warning. The system  100  constructs the obstacle warning envelope  250  and evaluates the obstacle  260  based on flight specific parameters such as the flight path. This can reduce the workload of the flight crew, thus enabling improved safety and flight management. 
         [0030]    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.