Apparatus and method of displaying an aircraft's position

An aircraft display system (100) includes a first device (102) providing (402) flight data of a selected flight path of an aircraft (214), a device (106, 114) providing (404) a plurality of data points representative of the terrain (302) below the selected flight path, a processor (104) generating (406) display commands from the flight data and the plurality of data points, and a display (116) coupled to receive the display commands and operable to render (408) in a perspective view an icon representative of the aircraft (214) and the terrain (302) near the aircraft (214).

FIELD

The present invention generally relates to an apparatus and a method of presenting the current position of an aircraft on an electronic display and more particularly to a method for presenting a vertical representation of the aircraft in relation to its surrounding environment.

BACKGROUND

Modern map displays, particularly those used in aircraft for flight planning and monitoring, are capable of displaying a considerable amount of information such as terrain information and flight planning information. The terrain information may include situational awareness terrain and cautions that identify potential hazards. Flight planning information may include, for example, flight path and altitude information useful to the pilot.

These electronic instrumentation displays continue to advance in sophistication, achieving increasingly higher levels of information density and, consequently, presenting a greater amount of visual information to be perceived and understood by the operator, e.g., pilot. It is important that visual displays provide a proper cognitive mapping between what the operator is trying to achieve and the information available to accomplish the task.

Data generated vertical profile displays do not provide any indication of the physical dimensions of the geographical area being presented. Known vertical profiles are shown as a “flat” two-dimensional image. However, the data available is not two-dimensional in nature and may be gathered as a corridor of unspecified width projected along the flight path, or as a forward-looking cone. It would be beneficial to pilots if more of the available information could be presented.

Accordingly, it is desirable to provide an apparatus and method for illustrating the terrain near the flight path on a vertical display in a more intuitive manner. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background.

BRIEF SUMMARY OF THE INVENTION

An aircraft display system includes a first device providing flight data of a selected flight path of an aircraft, a device providing a plurality of data points representative of the terrain below the selected flight path, a processor generating display commands from the flight data and the plurality of data points, and a display coupled to receive the display commands and operable to render in a perspective view an icon representative of the aircraft and the terrain near the aircraft.

DETAILED DESCRIPTION

The mapping methods described herein may be used with a variety of aircraft, such as planes and helicopters. The aviation environment is described herein as the exemplary embodiment and may include navigation from point to point or approach and landing at an airport. Generally a top view display is presented in conjunction with the vertical view presented herein. Various types of maps may be used for display on the top view, for example, road maps, terrain maps, aviation maps, and topographical maps.

Some applications may require more than one monitor, for example, a head down display screen, to accomplish the mission. These monitors may include a two dimensional moving map display and a three dimensional perspective display. A moving map display may include a top-down view of the aircraft, the flight plan, and the surrounding environment. Various symbols are utilized to denote navigational cues (e.g., waypoint symbols, line segments interconnecting the waypoint symbols, range rings) and nearby environmental features (e.g., terrain, weather conditions, political boundaries, etc).

Three dimensional perspective representations of terrain and flight planning information provide better spatial understanding and situation awareness and therefore reduce the navigational workload for a flight crew. A flight path display with a terrain underlay will also significantly enhance the perception of depth and relative location during the flight path visualization therefore reducing flight crew work load and improving the vertical awareness relative to terrain.

A perspective vertical view in accordance with the exemplary embodiment provides additional information regarding how the vertical profile data is gathered and analyzed. This three-dimensional data presentation will give the pilots the ability to better understand the vertical profile without a data overload of a full three-dimensional navigation display.

The perspective display provides a pilot (or other observer) with important navigational information. The perspective display provides information regarding the aircraft's orientation (e.g., the aircraft's attitude, altitude, pitch, roll, etc.) and aspects of nearby geographical features in an intuitive manner. Thus, a pilot may refer to the perspective vertical display when navigating around a geographical feature, such as a mountain.

Alternate embodiments of the present invention to those described below may utilize whatever navigation system signals are available, for example a ground based navigational system, a GPS navigation aid, a flight management system, and an inertial navigation system, to dynamically calibrate and determine a precise course.

Referring toFIG. 1, a known exemplary flight deck display system is depicted and will be described. The system100includes a user interface102, a processor104, one or more terrain databases106, one or more navigation databases108, various sensors112, various external data sources114, and a display device116. The user interface102is in operable communication with the processor104and is configured to receive input from a user109(e.g., a pilot) and, in response to the user input, supply command signals to the processor104. The user interface102may be any one, or combination, of various known user interface devices including, but not limited to, a cursor control device (CCD)107, such as a mouse, a trackball, or joystick, and/or a keyboard, one or more buttons, switches, or knobs. In the depicted embodiment, the user interface102includes a CCD107and a keyboard111. The user109uses the CCD107to, among other things, move a cursor symbol on the display screen (seeFIG. 2), and may use the keyboard111to, among other things, input textual data.

The processor104may be any one of numerous known general-purpose microprocessors or an application specific processor that operates in response to program instructions. In the depicted embodiment, the processor104includes on-board RAM (random access memory)103, and on-board ROM (read only memory)105. The program instructions that control the processor104may be stored in either or both the RAM103and the ROM105. For example, the operating system software may be stored in the ROM105, whereas various operating mode software routines and various operational parameters may be stored in the RAM103. It will be appreciated that this is merely exemplary of one scheme for storing operating system software and software routines, and that various other storage schemes may be implemented. It will also be appreciated that the processor104may be implemented using various other circuits, not just a programmable processor. For example, digital logic circuits and analog signal processing circuits could also be used.

No matter how the processor104is specifically implemented, it is in operable communication with the terrain databases106, the navigation databases108, and the display device116, and is coupled to receive various types of inertial data from the various sensors112, and various other avionics-related data from the external data sources114. The processor104is configured, in response to the inertial data and the avionics-related data, to selectively retrieve terrain data from one or more of the terrain databases106and navigation data from one or more of the navigation databases108(including surface features such as roads), and to supply appropriate display commands to the display device116. The display device116, in response to the display commands, selectively renders various types of textual, graphic, and/or iconic information. The preferred manner in which the textual, graphic, and/or iconic information are rendered by the display device116will be described in more detail further below. Before doing so, however, a brief description of the databases106,108, the sensors112, and the external data sources114, at least in the depicted embodiment, will be provided.

The terrain databases106include various types of data representative of the terrain over which the aircraft is flying, and the navigation databases108include various types of navigation-related data. These navigation-related data include various flight plan related data such as, for example, waypoints, distances between waypoints, headings between waypoints, data related to different airports, navigational aids, obstructions, special use airspace, political boundaries, communication frequencies, and aircraft approach information. It will be appreciated that, although the terrain databases106and the navigation databases108are, for clarity and convenience, shown as being stored separate from the processor104, all or portions of either or both of these databases106,108could be loaded into the RAM103, or integrally formed as part of the processor104, and/or RAM103, and/or ROM105. The terrain databases106and navigation databases108could also be part of a device or system that is physically separate from the system100.

The sensors112may be implemented using various types of inertial sensors, systems, and or subsystems, now known or developed in the future, for supplying various types of inertial data. The inertial data may also vary, but preferably include data representative of the state of the aircraft such as, for example, aircraft speed, heading, altitude, and attitude. The number and type of external data sources114may also vary. For example, the external systems (or subsystems) may include, for example, a terrain avoidance and warning system (TAWS), a traffic and collision avoidance system (TCAS), a runway awareness and advisory system (RAAS), a flight director, and a navigation computer, just to name a few. However, for ease of description and illustration, only an instrument landing system (ILS) receiver118and a global position system (GPS) receiver122are depicted inFIG. 1.

The display device116, as noted above, in response to display commands supplied from the processor104, selectively renders various textual, graphic, and/or iconic information, and thereby supply visual feedback to the user109. It will be appreciated that the display device116may be implemented using any one of numerous known display devices suitable for rendering textual, graphic, and/or iconic information in a format viewable by the user109. Non-limiting examples of such display devices include various cathode ray tube (CRT) displays, and various flat panel displays such as various types of LCD (liquid crystal display) and TFT (thin film transistor) displays. The display device116may additionally be implemented as a panel mounted display, a HUD (head-up display) projection, or any one of numerous known technologies. It is additionally noted that the display device116may be configured as any one of numerous types of aircraft flight deck displays. For example, it may be configured as a multi-function display, a horizontal situation indicator, or a vertical situation indicator, just to name a few. In the depicted embodiment, however, the display device116is configured as a navigation display.

The display device116is used to display various images and data, in both a graphical and a textual format, and to supply visual feedback to the user109in response to the user input commands supplied by the user109to the user interface102. It will be appreciated that the display device116may be implemented using any one of numerous known display devices suitable for rendering image and/or text data in a format viewable by the user109. Non-limiting examples of such display devices include various cathode ray tube (CRT) displays, and various flat panel displays such as, various types of LCD (liquid crystal display) and TFT (thin film transistor) displays. The display device116may additionally be implemented as a panel mounted display, a HUD (head-up display) projection, or any one of numerous known technologies.

With reference toFIG. 2, it seen that a known display108includes a display area200in which multiple graphical and textual images may be simultaneously displayed. For example, a vertical profile206, and a lateral map208may be displayed simultaneously, alone, or in various combinations. General flight-related data may be displayed including various types of data related to the flight plan of the aircraft. Such data includes, but is not limited to, the flight identifier, route iteration number, a waypoint list and associated information, such as bearing and time to arrive, just to name a few. It will be appreciated that the general flight-related data may additionally include various types of data associated with various types of flight hazards. Examples of these, and other types of data that may be displayed, are disclosed in U.S. Pat. No. 6,289,277, entitled “Interfaces for Planning Vehicle Routes,” which is assigned to the assignee of the present application, and the entirety of which is hereby incorporated by reference.

The lateral map208includes a top-view aircraft symbol224, one or more waypoint symbols226A-D, line segments228A-D that interconnect the waypoint symbols226, and one or more range rings230. The lateral map208also preferably includes various map features including, but not limited to, terrain, political boundaries, and navigation aids, which, for clarity, are not shown inFIG. 2. The range rings230, only one of which is shown inFIG. 2, indicate nautical distance from the top-view aircraft symbol224. In the illustrated embodiment, the range ring230includes a range indicator232, which displays the lateral distance from the aircraft's present position to the position on the lateral map202that corresponds to the range ring230(e.g., 200 nautical miles). It will be appreciated that the value of the range indicator232may be set manually or automatically, via a non-illustrated a pop-up menu.

The vertical profile206includes a side-view aircraft symbol214, one or more waypoint symbols216A-D, line segments218A-D that interconnects the waypoint symbols216, a vertical axis220, and a horizontal axis222. The waypoint symbols216and interconnecting line segments218correspond to the current flight path and flight plan of the aircraft. The vertical axis220represents aircraft altitude and is suitably graduated with altitude values (not shown), and the horizontal axis222represents aircraft lateral position and is suitably graduated with lateral distance values (not shown). It will be appreciated that the horizontal axis222could alternatively be graduated with time values in addition to, or instead of, lateral distance values.

Referring toFIG. 3and in accordance with the exemplary embodiment, a vertical profile206and a lateral map208are illustrated on a display300in which elements similar to those ofFIG. 2bear the same reference numeral. However, instead of simply displaying a horizontal axis222on the vertical profile206, a representative image302of the terrain is shown. The terrain is illustrated as a series of planes in a perspective view providing the pilot a symbolic view of the terrain beneath, around, and ahead of the aircraft214. Information determining the image of the terrain may be obtained from the terrain database106, the external data source114, for example, a terrain avoidance and warning system (TAWS), or other methods. The representative image302is generated from a plurality of datapoints provided from, for example, the Defense Mapping Agency.

The representative image302of the terrain on the vertical profile206is also designed to show the pilot the resolution of the terrain data that is used to generate the representative image302. The pilot will, in all likelihood, fly directly over some of the terrain datapoints or at least close to some of them. Hence, the swath of terrain may show the aircraft's path crossing vertices as well as planes.

If the aircraft path crosses a vertex, then the pilot knows that the terrain height below is a true, measured point. If the path is crossing a plane between vertices, the terrain height shown is interpolated from the adjacent measured data points.

The primary purpose of the representative image302shown inFIG. 3is to provide the pilot with this information on the “trueness” of the profile, whether it is measured or calculated. This could be important in areas where there are extreme altitude changes over a short horizontal distance, for example, a cliff side. If the terrain mapping agency measures altitudes every 100 meters, one point may be on the top of the cliff at 200 meters, and the next in the valley, at zero meters. If the pilot is flying over a point halfway between the two, the software takes an average of the two readings, giving an altitude of the terrain below the aircraft of 100 meters. In actuality, the altitude could be, for example, zero meters, 30 meters, 100 meters, or 250 meters.

The traditional vertical profile can only show a single line, with a mix of measured points and interpolated points. The perspective view will show the pilot that the terrain adjacent to the flight path is undergoing a drastic change in altitude and that the representation should be used with an understanding of such.

In accordance with the exemplary embodiment and referring to the flow chart ofFIG. 4, a flight path is selected402. A number of data points representative of the terrain are determined404from information supplied from the terrain database106or the external data source114. A processor104constructs406display commands from the flight path and data points, and provides them to the display116for displaying408a perspective vertical representation of an aircraft icon214in relation to a representation of the terrain.