RIS-Assisted Cooperative Positioning for Smart Vehicles with Extended Kalman Filter and AOA Measurements

Based on urban vehicle safety applications where global positioning system (GPS) and inertial navigation systems cannot provide the required positioning accuracy, an cooperative positioning (CP) method that utilizes reconfigurable intelligent surfaces (RIS) is proposed for smart vehicles. In our considered scenario, one roadside unit (RSU), served as a base station, and two time-synchronized RISs, assisted in enhancing CP auxiliary information estimation, compose the basic positioning unit. Due to the introduce of RIS, the LOS communication link between the RSU and smart vehicle can be added in a form of virtual LOS (VLOS) signal, it greatly increases the estimation accuracy of the equivalent location-related angle of arrival (AOA). Then, we use extended Kalman filter (EKF) to fuse AOA information and related inertial navigation parameters to conduct positioning and tracking. Simulation results show that the proposed RIS-assisted CP can achieve decimeter-level positioning accuracy, which can be viewed as a better candidate for future intelligent vehicle positioning system.