V2I electromagnetic system for lateral position estimation of a vehicle

A vehicle to infrastructure (V2I) electromagnetic system is studied to estimate the lateral position of a vehicle in its lane. This system can be include in an advanced driving assistance system (ADAS) in order to provide the vehicle lateral positions to warn the driver in case of an involuntary road lane departure or to drive the car in case of autonomous driving. The developed system consists of passive electromagnetic transponders embedded in the lane markings, each one contains two surface acoustic wave (SAW) resonators that have two different center frequencies, and a hyperfrequency transceiver embedded in the lateral sides of the vehicle. The system operates in the ultrahigh frequency (UHF) band. The phase difference of arrival (PDoA) method for distance measurement is used to estimate the absolute lateral distance between the vehicle and the lane markings. A method is developed to recover the useful phases from the global response of the system using its frequency response, around the two resonance frequencies of the SAW resonators. The system is tested in outdoor environment and the results of the useful phases recovering method are accurate, where the absolute distance estimation gives an error lower than 3 cm.