GB2289560A - Information systems - Google Patents

Abstract

An information provision system for use with vehicles comprising an information store reader 13, for reading from a store, information appertaining to a geographical region in, over, or through which a vehicle is planned to travel, the store having individually accessible addresses, at which addresses information appertaining to different parts of the region is stored, global positioning system (GPS) data receiving means 1, address selection means, and information play-back means 14, the address selection means being responsive to GPS data received by said receiving means indicative of the geographical position of the vehicle, for selecting one or more of said addresses which correspond to said geographical position, whereby data stored thereat is made available to the said play-back means. <IMAGE>

Description

IMPROVEMENTS IN OR RELATING TO INFORMATION SYSTEMS This invention relates to information provision systems for use in vehicles.

The term 'vehicle' when used herein, includes any kind of passenger transportation vehicle such as aircraft, ships, and road or rail vehicles, but more especially it relates to rail or road vehicles.

There is a requirement for the provision in vehicles of an information system which serves to provide for passenger information appertaining to the geographical region through which a vehicle is travelling. The information provided may have educational and/or entertainment value, and additionally or alternatively it may have practical value to the crew or driver of the vehicle, for example.

According to the present invention, an information provision system for use with vehicles comprises an information store reader, for reading from a store, information appertaining to a geographical region in, over, or through which a vehicle is planned to travel, the store having individually accessible addresses, at which addresses information appertaining to different parts of the region is stored, global positioning system (GPS) data receiving means, address selection means, and information play-back means, the address selection means being responsive to GPS data received by said receiving means indicative of the geographical position of the vehicle. for selecting one or more of said addresses which correspond to said geographical position, whereby data stored thereat is made available to the said play-back means.

In this way, information appertaining to places of interest passed by a car, bus or train, for example can be played back for reception by driver or passengers at appropriate times, as such places are passed and preferably. although not essentially, when such places are on view to passengers.

The store may comprise a Read/write store or a ROM such as a 'hard disc' or a 'compact disc' for example which is located (in use) so as to be accessible to and operatively associated with the said reader.

Alternatively the store may be remotely located and accessed by the reader using radio communication techniques, such as cellular radio communication techniques.

The GPS data receiving means may simply comprise an electrical connector to which data signals from a GPS radio receiver are fed, or alternativelv it may comprise a complete GPS data receiver and aerial system.

The play-back means may comprise facilities for audio and/or video play-back of infolmation from an appropriate stored address.

The address selector means may comprise a GPS data store and a data processor responsive to GPS data in the GPS data store for initiating release of information from an appropriate address in the information store at an appropriate time.

The processor may be responsive to the GPS data store for computing vehicle speed, vehicle acceleration. and direction of vehicle travel or bearing, information play-back being controlled in dependence upon one or more of these computed parameters.

Thus it may be arranged that general information appertaining to a place of interest may be released when a vehicle is in the vicinity of the place, or when it is in the vicinity of the place and approaching the place from a predetermined direction.

Alternatively, such general information may be released when a vehicle is in the vicinity of the place supplemented with other information chosen in accordance with the direction from which the place is approached.

The processor may include GPS data validity checking means, responsive to the computed parameters of speed and acceleration, for validating GPS data and a message interface/trigger store which serves to control selection of information in dependence upon GPS data validity, direction of vehicle travel and vehicle position.

One embodiment of the invention will now be described by way of example only, with reference to the accompanying drawings, in which FIGURE 1 is a generally schematic block diagram of a GPS driven information system; FIGURE 2 is a diagram illustrating one basis for information selection; FIGURE 3 is a matrix cell diagram illustrating a technique for increasing search speed; and FIGURE 4 is a diagram showing means of reducing the effect of possible GPS inaccuracies.

Referring now to Figure 1, a GPS driven information system comprises a GPS receiver 1, which is arranged to feed a coordinate conversion unit 2. The co-ordinate conversion unit 2 serves to convert data appertaining to the longitude and latitude of a position to corresponding x and y co-ordinates such as Ordnance Survey map co-ordinates for example. Apparatus including the GPS receiver 1 and co-ordinate conversion unit 2 is mounted in a vehicle and thus the position of the vehicle in terms of Ordnance Survey co-ordinates, is provided by means of GPS data on a line 3.

The GPS data on the line 3 is fed to a GPS information store and processor unit 4. The processor which forms a part of the unit 4 calculates from present and previous stored values appertaining to vehicle position and vehicle speed, the direction of vehicle travel. Data appertaining to these parameters is fed via lines 5, 6 and 7 to a validity checking unit 8. The validity of current information relating to vehicle position is checked by using the information in combination with previous positional measurements to compute speed and acceleration. If the results of these computations fall within predetermined limits, then the positional information is deemed to be valid. Data appertaining to vehicle position, direction of travel and validity are fed to a message trigger and store unit 9. via lines 10, 11 and 12 respectively. Taking account of the vehicle position, the direction from which the position is being approached and the validity of current data, information from a predetermined address in a message ROM store (not shown) is read by an information store reader 13 and released to a user interface 14. Control of the apparatus, thus far described, is effected by means of an operator interface unit 15.

It will be apparent that the message trigger and store unit 9, controls the moment at which a message is released to the user interface 14, by the information store reader 13. It is also used to facilitate a fast search procedure for messages which will subsequently be released. It is vital that erroneous position indications should be detected so that messages are not triggered for release when the vehicle is in an inappropriate position. This as hereinbefore explained is achieved by ignoring positional data which produces unlikely speed and/or acceleration figures. In order to improve the reliability of this facility, speed. bearing and acceleration figures may be averaged over a number of samples in order to smooth the results. Different time constants may be used, in accordance with the parameter computed and it follows that bearing data requires an averaging position having a time constant long enough for at least a few metres of travel in both x and y co-ordinate directions, in order to give reasonable accuracy.

The coarseness of bearing indications may be varied in accordance with speed and thus for very low speeds, coarse bearing indications may be acceptable.

It will be apparent that the validity of a position fix can also be checked with the value for estimated accuracy. number of satellites in view and in use etc.

When there are only a small number of messages appertaining to a particular geographical region and vehicle speed is low, fast search speeds are not necessary. However, when a large number of messages appertain to a relative small geographical area, high search speed may be important, and thus a list of messages may be provided identifying the co-ordinates of a trigger location, the radius of trigger area and valid direction of travel to cause triggering. i.e. to release information appertaining to a particular location.

Message status flags may conveniently be associated with each message, indicating whether a particular message has already been triggered or is waiting to be released, printed or played-back.

Search speed may be increased progressively as shown in Figure 2, by determining whether a current location is within predetermined minimum and maximum x and y co-ordinates. By carrying out the checks, using x and y co-ordinates as shown in Figure 2, messages which are identified as not being within a circular area 16 (as defined by x and y maximum and minimum co-ordinates), are ignored and a correct message may be rapidly identified.

When a large number of messages apply to a particular region, and when vehicle speeds are high. there may not be time available to search for every message for each new position fix.

By dividing an area of interest into cells 17, as shown in Figure 3, and by associating different messages with different groups of cells, as indicated by shaded areas 18 and 19. enhanced search speed may be facilitated. It will be readily apparent however, that the size of each cell depends on memory availability and on the size of an area to be covered. Each cell may point to a linked list of messages which may be triggered in an area, or each cell may be triggered in that area, or each cell may contain a number of message areas if it is large. Alternatively, if each cell represents a very small area, a number of cells may map the shape of a single message trigger area as shown by the shaded areas 18 and 19 in Figure 3. This method can be used to reduce the number of messages which must be checked each time a new position fix is obtained.

The cell array and linked lists described above, would normally be calculated as part of an initialisation routine when a software program is started. Effectively, memory storage area is traded for improved search speed.

Hash coding may be used as used in a Cache memory system. Hash coding will allow messages in the close vicinity to be identified by their hash code, being the same as that generated for a current position fix.

Because of jitter which is purposely applied to GPS signals, the accuracy of a stand alone GPS receiver is only to within about 100 metres which means that trigger areas need to be at least 100 metres in radius, and preferably larger. This is inconvenient, especially since much of the time measurement accuracy is better than to within 100 metres. To improve trigger point accuracy, triggering of a message is effected at the closest point of approach of a vehicle to the centre of a circle 20. as shown in Figure 4.

When a vehicle is inside the circle 20 which defines the boundary of a message trigger area, the distance of a vehicle from the centre and the rate of change of that distance is computed.

When the rate of change becomes positive, an appropriate message is triggered. Thus the message will be triggered when the current position starts to move away from the centre of the circle 20.

It is apparent that non circular trigger areas could be defined, and provision may for example be made to provide polygon shaped trigger areas by entry in a store of a list of boundary lines.

The operator interface 15 is necessary in order to allow an operator to add messages to the system. The provision of a graphical display in addition would help to position messages and check the correct entry of position, shape, size and valid trigger bearings. A graphical interface would also show the movement and track of a vehicle in which the system is mounted.

In one embodiment of the invention, text messages may be printed on a screen describing an item or area of interest.

Additionally. voice messages may be played through an audio system, which voice messages may be the same as, or complimentary to the text messages.

Various message types may be identified and a user selectable filter could be employed to allow only messages with a desired character or content to be triggered. For example, messages may be historical in character, general interest, scenic, or things to do etc. and a user may wish only historical information to be presented and this facility may be facilitated by means of a suitable selectable filter.

Graphics, sound, video, etc may also be used as a part of a system for the presentation of tourist information triggered by the GPS system. For example, progress of a journey on a map, photographs of interest, music for entertainment, speech commentary and supporting text etc, use of multi-media being controlled and appropriately triggered by the system.

The message store reader 13 may include in use an appropriately selected store containing information messages which are stored in part, or in total, allowing each message format to be constructed using several messages or sub-messages in combination. Frequently used message sections may be stored separately and revised in order as appropriate to reduce storage requirement.

The GPS information store 4 may include a facility whereby GPS position information is stored in a disc file enabling play-back of recorded journeys to be effected.

Various modifications may be made to the invention as just before described and for example, the GPS information store which is accessed by the reader 13, may be remotely located and accessed by the reader 13 using radio communication techniques such as those used in cellular mobile radio systems.

Claims (11)

1. An information provision system for use with vehicles comprising an information store reader, for reading from a store, information appertaining to a geographical region in, over, or through which a vehicle is planned to travel, the store having individually accessible addresses, at which addresses information appertaining to different parts of the region is stored, global positioning system (GPS) data receiving means, address selection means, and information play-back means, the address selection means being responsive to GPS data received by said receiving means indicative of the geographical position of the vehicle, for selecting one or more of said addresses which correspond to said geographical position, whereby data stored thereat is made available to the said play-back means.

2. A system as claimed in Claim 1. comprising a store which is located in use so as to be accessible to and operatively associated with the said reader.

3. A system as claimed in Claim 1, wherein the reader is adapted to communicate with the store, which is remotely located, using radio communication techniques.

4. A system as claimed in any preceding claim, wherein the GPS data receiving means comprises an electrical connector to which data signals from a GPS radio receiver are fed.

5. A system as claimed in any of claims 1 to 3, wherein the GPS data receiving means comprises a complete GPS data receiver and aerial system.

6. A system as claimed in any preceding claim, wherein the play-back means comprises facilities for audio and/or video playback of information from an appropriate stored address.

7. A system as claimed in any preceding claim, wherein the address selector means comprises a GPS data store and a data processor responsive to GPS data in the GPS data store for initiating release of information from an appropriate address in the information store at an appropriate time.

8. A system as claimed in Claim 7, wherein the processor is responsive to the GPS data store for computing vehicle speed, vehicle acceleration, and direction of vehicle travel or bearing, information play-back being controlled in dependence upon one or more of these computed parameters.

9. A system as claimed in Claim 7 or Claim 8, wherein an appropriate address is selected in dependence upon vehicle position as indicated by GPS data and the direction from which the vehicle is approaching this position as indicated by previous positions of the vehicle as indicated by GPS data.

10. A system as claimed in any of claims 7 to 9, wherein the processor includes GPS data validity checking means, responsive to the computed parameters of speed and acceleration, for validating GPS data and a message interface/trigger store which serves to control selection of information in dependence upon GPS data validity, direction of vehicle travel and vehicle position.

11. A system as claimed in Claim 1 and substantially as hereinbefore described with reference to the accompanying drawings.