GB2165427A - Dynamic graphic displays in vehicles - Google Patents

Abstract

A dynamic graphics display is provided in a vehicle, e.g. an aircraft, by transmitting thereto digital topographic data such as might define fixed airfield installations and positions of parked aircraft. The data is received and stored and processed by an on-board computer according to the position of the aircraft obtained from navigational aids, the output being e.g. the airfield as viewed from the current position of the aircraft. This is displayed in response to a control signal. The display may be in colour to distinguish fixed and transient features. <IMAGE>

Description

SPECIFICATION Dynamic graphic displays in avionics This invention relates to apparatus for providing dynamic graphics displays in aircraft.

Recent accidents involving aircraft in both the U.S.A. and Europe have focussed attention on the inadequacy of the way in which airport surface movement is gathered, as reported in Aviation Week and Space Technology, 12 December1983, p.

30, "Pilots revive complaints after Madrid crash".

Another is the manner in which such information is conveyed to aircraft pilots; see The Journal of Navigation, Vol. 33, No. 1, January 1980, pp 64--79, "Airborne Traffic-Situation Display", R. L. Ford.

Misunderstandings are a common feature of aircraft accidents, and Ford has referred to the well-known fact that people trying to describe a particular situation to each other frequently feel a need to explain themselves by drawing a diagram.

RCA proposed in the 1940's TELERAN, a system which transmits to aircraft a television image of ground radar displays. Two obstacles prevented development, the difficulty of finding space in the cockpit for the display and the difficulty of limiting the data to a particular aircraft to what was relevant. A later proposal which was designed to overcome the latter problem was to move a television camera over a model of the airport, the camera movement being controlled by the airport radar determining the position and movement of an approaching airport.

The television signals were then transmitted to a monitor screen in the aircraft cockpit, thereby providing the pilot with an imitation of the scene he would expect to see if visibility allowed. However there was still the cockpit space problem. Also, such a system could only handle one aircraft at a time.

The advent of Mode-S, a development of secondary surveillance radar enabling additional data to be sent from the ground to the aircraft, will soon overcome the data limitation. Mode-S also allows ground control to address an individual aircraft exclusively. The trend towards the use of cathode ray tube monitors to combine many cockpit display functions overcomes the space problem. Indeed, the FAA is moving toward support for traffic displays in aircraft cockpits, see Aviation Week and Space Technology, July 1983, p. 128 "FAA Staff document endorses use of cockpit traffic displays".

According to the present invention there is provided apparatus for providing dynamic graphics displays in a vehicle comprising means for receiving, demodulating and storing digitally encoded data signals conveying representational information of a defined topographical situation, data processing means responsive to navigation information relating to the vehicle's current navigation status to process the stored data selectively to derive therefrom data relating to an image of relevance to the vehicle at a particular time, and means for displaying said image in response to a control signal.

Embodiments of the invention will now be described with reference to the accompanying drawing which depicts in block diagram form a dynamic graphics display system for aircraft.

An airport installation includes a transmitter and a database 11. The database 11 contains digital information relating to the airport structure, which is basically non-changing, plus additional information which may vary with surrounding traffic, e.g. as supplied by the airport radar 12, or environmental conditions or operational restraints, as supplied by airport traffic control 13. The information held in the data base 11 is continuously broadcast to any aircraft in the area.

In the aircraft a receiver demodulator decodes the data received and places it in an onboard store. An onboard computer extracts the data of relevance at the particular time and processes it to provide an image on a display screen. The image may be a topographical image, e.g. a map with contours, a picture or text. The computer also receives an input from the aircrafts' own navigation equipment which enables selection of data relevant to the aircrafts' own present position. Finally the pilot has a computer control means whereby he can call up data of particular relevance or alter the way in which it is displayed, e.g. by changing the scale.

The invention makes use of currently available data processing techniques whereby digital data relating to a three-dimensional image can be processed to "rotate" the image to provide different views as required. This processing technique is well established in the field of computer aided design where, for example, an apparent 3-dimensional representation of say a car can be manipulated to form a view of the car from any angle. Using the same techniques a representation of an airport can be provided viewed from the position of the aircraft, the view being altered as the aircraft's position relative to the airport alters.

The above equipment package would allow the following functions to be achieved -- all of which could make a real contribution to safety.

(a) During taxiing from loading ramp to take-off position a picture can be presented representing the plan view of the airport or that part of the taxi system which is of immediate concern. Fixed structures like taxiways and gate fingers can be shown in one colour and temporary operationally no-go areas like taxiways being resurfaced can be displayed in a different colour. Athird colour could be used by ATC to convey to a particular aircraft the particular route to be taxied thus easing the reliance on verbal instructions. The position of other aircraft could be superimposed thus reducing the probability of collision. With the exception of taxiing instructions the same data would apply to all aircraft. The 'map' details are fixed with time, position of other aircraft changes.

(b) During take-offthe display can show the climbout profile as planned as well as deviation from it.

This would be unique to each aircraft.

(c) During flight the display can show the relevant airways structure, position of Navaids and their status updated by ATC. The airways map could be organised such as to show only that part of the airways which is relevant to the flight. Superimpose on itterrain contours (of interest to helicopters) and actual position as derived by onboard aids. As the aircraft moves along, the "map" moves as well.

Note that this map is not a piece of paper previously drawn and installed, it is a map drawn by computer in the aircraft on a CRT/LCD during the flight and derived from digital data picked up from ground broadcasts.

(d) During approach the display can draw a picture of what the pilot would see through his window if visibility allowed him to do so. Thus a bird's eye view of hangars, runways, control tower and the like. Itwould all be possible from digital transmissions broadcast omnidirectionally to all aircraft in radio range, the aircraft computer working out the "view" from that general data and knowledge of position of that aircraft from onboard Navaids.

(e) Helicopters operating to North Sea oil rigs represent a particularly intresting opportunity. On way to the rig the display could showthe airways structure and planned track. When nearing the rig and in radio range it could pick up broadcast information showing in map form the position of the rig in relation to other rigs. When getting closer the scale changes annd the rig outline is shown as a bird's eye view again based on digital information broadcast to all but interpreted by the onboard computer depending on position. The helicopter has to land below but in close proximity to the drilling tower, above near by shipping with tall masts and clear of cranes whose position may continually alter. All could be continually shown on a display onboard with detail and scale continuously changing depending upon range.

In the case of (a) consider a two runway airport with parallel taxiways, four rapid turn-offs, a large terminal building and 50 gates. An outline map could possibly be defined using say 500 points linked in various ways. Assuming a surface area of4 x 4 km and a 2 m resolution definition would require some 12 bits in each ofx and y directions plus check bits and colour.If the information is in the form "Draw a line ofcolour'a'fromx1 Y1 tox2 Y2 and thence colour 'b' to x2 y, and thence colour 'c' to x4 /4 etc" we would need about 35 bits per point or a total of under 20,000 bits to define in map form the essential features of the airport. If transmission is in a VHF slot limiting us to say 4 bits, the entire information is transmitted in 5 seconds. A 5 second acquisition time is no problem either at start-up time or on approach to land.

Mode S is a variant of SSR which allows data exchange. The up-link is at 1030 MHz and the aircraft replies at 1090 MHz. Each interrogation contains a 24 bit discrete address followed by data bits up to a total of 112 bits. There is also an extended length message capability allowing up to 1980 bit message segments. The data transmission facility is planned forATC purposes and may be used to provide flight advisory services such as weather reports, automated terminal information etc. This link can therefore cope with some of the functions envisaged above though it is unlikely that all the required data could be accommodated. It seems therefore more likely that the high volume data of local interest, e.g. drawing details of an oil rig or map details of an airport must be transmitted via some other means like a VHF channel.

A possibility would be to switch one of the VHF receivers in the aircraft to the data broadcast frequency for sufficient duration to store all data related to the destination airport where it is transmitted at the maximum rate consistent with the bandwidth and that slowly changing information like other aircraft movements is transmitted as very low data rate superimposed on normal voice on the normal ATC VHF channel.

One of the attractions of the invention is that relevant information may be displayed in the cockpit with an optimum and changing scale without requiring any new technology nor expensive development.

Although the above relates only to aircraft operations, there are parallels both in marine and road applications. For marine applications a series of shore transmitters can broadcast data from which a unit onboard can draw on a CRT/LCD a section of chart relevant to the ship's position. Superimposed could be the state of Navaids in the area updated from notice to mariners, and possibly the state of other traffic as well as own position.

For road applications a display mounted in the car can draw a map of the road network ahead showing the state of the road (e.g. roadworks) and the state of the traffic flow so one can choose the route with minimum delay. The map could also give guidance on route to be followed to a particular destination.

Claims (8)

1. Apparatus for providing dynamic graphics displays in a vehicle comprising means for receiving, demodulating and storing digitally encoded data signals conveying representational information of a defined topographical situation, data processing means responsive to navigational information relating to the vehicle's current navigation status to process the stored data selectively to derive therefrom data relating to an image of relevance to the vehicle at a particular time, and means for displaying said image in response to a control signal.

2. Apparatus according to claim 1 wherein the data processing means is programmed to modify the selection and processing of data from the store in real time to generate a continuously changing displayed image relevant to the movement of the vehicle.

3. Apparatus according to claim 1 or 2 including means for superimposing of the displayed image additional visuai data or image(s) derived from navigational information relevant to the vehicle's current and predicted movements.

4. Apparatus according to any preceding claim including onboard means responsive to operator control to vary predetermined parameters of the displayed image(s).

5. Apparatus for providing dynamic graphics displays in a vehicle substantially as described with reference to the accompanying drawing.

6. A system for providing dynamic graphics displays in vehicles including a data store wherein are stored data conveying representational information of a defined topographical situation and means for broadcasting said data whereby a vehicle having receiving, demodulating and data processing means can selectively process received data to generate and display an image derived from the received data.

7. A system according to claim 6 further including means for inputting to said data store further data extraneous to the defined topological situation.

8. A system for providing dynamic graphics displays in a vehicle substantially as described with reference to the accompanying drawing.