US Patent 7610146 Vehicle position determining system and method

Vehicle positioning system and method for enabling a vehicle to determine its position while traveling on a road in which an identity of at least one marker is determined as the vehicle passes each marker. The position of each marker is determined from its identification, e.g., with reference to a database, and thus the position of the vehicle, can be determined. Various markers may be used, including fixed markers arranged proximate the road. If three such fixed markers are provided, the position of the vehicle can be determined using triangulation. The fixed markers may be visual markers, passive transponder-type markers, active transponder-type markers and/or reflectors.