The main contribution of DACAR experiments to the field of infrared road-vehicle communication is the use of vertical (continuous) transmissions in order to form a basic system allowing several communications at the same time. The study included various types of road-vehicle communication links which were developed and tested. Tests have been carried out in laboratory environments and on the Valeo test track in Mortefontaine near Paris. There are five types of tests: beam qualification, dynamic tests, transmission control in the lanes, trials in changing weather conditions and margins of the link. The purpose of the tests was to show that infrared (IR) can be used to transmit short or long messages, during the passage of a vehicle under the beams at a maximum speed of 180 km/h. It is possible to transmit messages from and to the roadside at a transmission rate higher than 600 kbits/s. If it is necessary to transmit more bits, combinations of several beacons are possible. Therefore IR is a good medium for dedicated short range vehicle-beacon communication (DSC). There exists a number of systems for some kind communication for road traffic and there is also a large offer of components for infrared systems. Therefore the first study period was used to summarize the state of the art of existing systems and investigate the market of infrared components. Systems as the ALISCOUT, tested out in LIBS and AUTOGUIDE, and the French system SAVE were object of study and a list of transmitting and receiving diodes was made. The features and disadvantages were discussed and based on these results the first design for an infra-red test system was made, concentrating on the vertical transmission plane. In March 1990 the mileage reference beacon was ready for preliminary tests and in June 1990 the tests with both types of beacon were carried out. The tests were completed in autumn 1990 and early 1991.
Abstract