Abstract:
The system comprises, on the one hand, a network of radiogoniometers (4 1 . . . 4 n ) which are coupled to at least one computer and are arranged at well-determined locations of areas of a region, and on the other hand, a set of radio distress beacons (2) which are arranged inside vehicles (1) moving within the areas of the region. The computer (6) comprises means of processing information emitted by the distress beacons and means of connection for locating and identifying in the region the beacons emitting distress signals and for transmitting the corresponding information to the emergency services (9) closest to the places of emission by the beacons.

Description:
This application is a continuation of application Ser. No. 07/828,852, filed as PCT/FR91/00465, Jul. 11 1991 now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     FIELD OF THE INVENTION 
     The present invention relates to an automatic system for locating and identifying vehicles in distress. 
     DISCUSSION OF THE BACKGROUND 
     The dispatch time of emergency services to places of road traffic accidents depends on the speed with which the latter are alerted and on the effective distance existing between the place of the incident and the nearest emergency station. 
     Thus the effectiveness of rescue operations is directly related to the infrastructure and to the human and hardware means at the disposal of the rescuers in order to cover a region, and the period which elapses between the incident and the alarm is mainly related to the place of the accident, to its nature and to the possible witnesses who may take up this alarm. 
     SUMMARY OF THE INVENTION 
     In order to minimise to the maximum the time which elapses between the accident and the alarm, the aim of the invention is to permit the automatic detection of serious accidents which may occur within the field in particular of road traffic in a specified region. 
     To this end, the subject of the invention is an automatic system for locating and identifying vehicles in distress, characterised in that it comprises, on the one hand, a network of radiogoniometers which are coupled to at least one computer and are arranged at well determined locations of areas of a region, and on the other hand, a set of radio distress beacons which are arranged inside vehicles moving within the areas of the region, and in that the computer comprises means of processing information emitted by the distress beacons and means of connection for locating and identifying in the region the beacons emitting distress signals and for transmitting the corresponding information to the emergency services closest to the places of emission by the beacons. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other characteristics and advantages of the invention will emerge below in the description which follows, given with reference to the attached drawings which represent: 
     FIG. 1, a system for locating and identifying vehicles in distress according to the invention. 
     FIG. 2, an embodiment of an electronic device arranged inside each beacon in order to permit the emission of distress signals. 
     FIG. 3, a sequence of types of messages capable of being transmitted by the beacons. 
     FIG. 4, an area descriptor addressing diagram. 
     FIG. 5, a flow diagram to illustrate a mode of programming the beacon. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     According to the invention each vehicle bearing the reference 1 in FIG. 1 is equipped with a distress beacon 2. It furthermore possesses sensors 3 enabling it to establish electrical or mechanical contact following a significant impact suffered by the vehicle, in respect of which it is assumed that the occupants of the vehicle are injured. The contact established by each sensor 3 enables the distress beacon 2 to start emitting on a specified radio frequency. A ground infrastructure consisting in FIG. 1 of radiogoniometers referenced from 4 1  to 4 n  permits reception and detection of this radio emission. Each sensor 4 1  to 4 n  possesses a goniometer coupled to a specific computer, not shown, which makes it possible to acknowledge in known manner on the basis of a chart the logging of the signal received. 
     A computer link 5 1  . . . 5 n  connects all the sensors 4 1  to 4 n  to a processing unit 6 which receives all the logging information and deduces therefrom the exact coordinates of the point of emission. Such a link may for example be constructed in the manner of that known and described in the report 668-2 of the Commission of Study No. 1 CCIR of the ITU of October 89 entitled &#34;Automatic monitoring and measurement of the radio frequency spectrum&#34;. The computer 6 placed in a listening and alarm centre, not shown, makes it possible to generate a call on the switched telephone network to an emergency centre 9 which is the closest to the place of the accident, and to supply the calculated geographical coordinates of the position of the vehicle involved in an accident. 
     The electronic device equipping the distress beacon 2 is represented diagrammatically in FIG. 2 inside a closed dashed line 10. It comprises, connected to a microprocessor 11, a clock 12, a memory 13, an impact sensor 14, a booster battery 15 and a radio emitter 16 which are coupled to at least two antennas 17 and 18 situated above and below the vehicle 1 in order to permit continuity of the emissions from the beacon even in the event that the vehicle turns round or turns over. The microprocessor 11 is connected to the dashboard 19 of the vehicle. A switch 20 is placed on the beacon to permit the cutting of power to the device of FIG. 2 via the booster battery 15. The booster battery 15 is moreover powered by the vehicle battery 21. According to a first embodiment of the invention, the emitter 16 can emit on two different frequencies, each of which may have a particular significance in order to enable the appropriate emergency services, such as the fire brigade, hospital services personnel and mechanical breakdown teams for removing the vehicle, to be moved to the site of the vehicle involved in an accident. The types of messages which are transmitted are messages which convey information about the type of vehicle involved in an accident, about its registration, about its insurance, possibly about the dealer&#39;s garage, etc. A test message may possibly be provided to permit testing of the correct operation of the beacon, without however triggering the emergency services. The frequencies and the messages transmitted over these channels are detected by the goniometers 4 1  to 4 n  and the angles of arrival of these frequencies are transmitted with the corresponding messages to the computer 6 which effects location of the vehicle 1. This location is determined in a known manner in latitude and longitude relative to the Greenwich meridian, for example, which enables, in the manner represented in FIG. 4, the geographical area in which the vehicle involved in an accident is situated to be defined with the aid of a conversion table 22. To determine a location, the conversion table calculates an area address in an area descriptor table stored in a memory of the computer 6 and an address for addressing a location table. The area z i  pointed to by the address conversion table 22 contains, in the manner represented at 25 in FIG. 4, all the information required for the rapid dispatch of the emergency means to the place of the accident. This information may consist, as represented in FIG. 4, of the telephone numbers of the fire brigade or police services closest to the place at which the accident took place. The address conversion table 22 also points, in the location/table 24, to the locality of the place closest to the accident, and the road on which it occurred. The computer 6 may thus deduce therefrom the number of kilometers separating the place of the accident from the locality. 
     The operation of a beacon is illustrated by steps 26 to 43 of the flow diagram of FIG. 5. In this flow diagram when, in steps 26 and 27, an impact is detected, a time delay of specified duration, 30 seconds for example, and illustrated by steps 28 to 31 and 42, 43, is triggered by the impact sensors 14 of the beacon in such a way as to enable the occupants of the vehicle to act on the dashboard 19 in order possibly to prevent the emissions of messages if it is noted that the impact which caused the triggering of the beacon does not justify the sending of distress signals. If at step 42 the stopping of the operation of the beacon is not carried out at the end of the 30 seconds elapsed, the microprocessor 11 executes steps 32 to 41 which permit messages to be sent regularly inside windows of specified duration t 0  of 15 seconds for example, with emission slot of duration t 1  of 1 second for example selected randomly inside each window of duration t 0 , so as to preclude two colliding vehicles, each having a beacon, being able to have a simultaneous emission cycle. At step 35 it is possible to stop the operation of the beacon by cutting the power to the latter through action on the switch 20. If this action is not carried out at step 35 the emission procedure is continued through execution of steps 37 to 41. 
     Naturally, according to the invention it is also possible to equip emergency vehicles with goniometers matched to the frequency range of the distress beacons. The attraction of this equipment is of course to be able to indicate to the driver of the emergency vehicle the general direction to be followed in order to reach the place of the accident. This solution is attractive in particular in the case of a vehicle involved in a night-time accident in a rural area for example.