Vehicular Localization With Using China Electronic License Plate System

In the past five years, electronic license plate (ELP) systems have been widely deployed in most China big cities, which provide a novel solution for vehicular localization. Since vehicular position information plays a crucial role in intelligent transportation systems (ITS), the ELP based vehicular localization method is studied to overcome the shortcoming of camera based method in this paper. The ELP system, a customized UHF RFID system, uses RFID tag as a electronic license plate and RFID reader as ELP reader. Thus, the vehicular localization problem is transformed as a ELP localization problem. After analyzing, a ranging based solution is proposed to solve the vehicular localization problem. A multi-frequency based phase difference of arrival (PDOA) ranging algorithm is utilized to calculate the distances between the ELP and antennas. Then, the localization problem is modeled as an optimization problem and the reason why traditional algorithm can not solve this problem is discussed. After that, a novel local search based algorithm is proposed to solve the localization problem. Various experiments are designed and performed to verify the proposed method. Experimental results show that the proposed method achieves a centimeter level ranging and localization accuracy and the proposed localization algorithm converges quickly.