Light beacon to be used in this and the road-to-vehicle communication method and road-to-vehicle communication system

摘要

PROBLEM TO BE SOLVED: To accurately measure speed information on traveling speed of a vehicle only with road-vehicle communication by an optical signal.;SOLUTION: Provided is a system which executes interactive communication by an optical signal between a vehicle-mounted device 2 mounted in a vehicle C and a light emitter and receiver 8 of an optical beacon 4 in a communication area A provided in a prescribed region on a road R. The optical beacon 4 receives pieces of uplink information UO1 and UO2 multiple times from the vehicle-mounted device 2 and acquires traveling position information, which is related to a traveling position of the vehicle C at the time when the plural pieces of uplink information UO1 and UO2 are transmitted, and calculates the speed information on the traveling speed of the vehicle C based on the acquired traveling position information.;COPYRIGHT: (C)2009,JPO&INPIT