GPS/IMU Integrated Relative Positioning for Moving Land Vehicles with V2V (Vehicle-to-Vehicle) Communication Module

In this paper, we present GPS/IMU integrated relative positioning algorithm based on pseudorange measurements with V2V communication module. More specifically, this algorithm does not calculate absolutely precise position but gets relative position directly just by utilizing pseudorange differences of CVS (Commonly Visible Satellite)s for the two specific vehicles. So it is cost-effective and simple to apply for real traffic system. Several steps of proposed algorithm are as follows. Firstly, each vehicle gets pseudoranges of visible satellites with GPS receiver and then broadcasts them to or receives them from other vehicles nearby with V2V communication module. Secondly, one vehicle searches for CVSs with other vehicles nearby and then calculates unbiased relative position with 1Hz output from pseudorange differences of CVSs. Simultaneously, that vehicle estimates relatively precise its own velocity with 10Hz output from GPS/IMU integration filter. Lastly, it performs filtering for the obtained relative position and estimates more accurate relative position with 10Hz output. The physical system for proposed algorithm mainly consists of three parts-the embedded computer to handle data, V2V communication module to communicate with other vehicles nearby and finally PWM board to control vehicle itself. V2V module also includes MEMS IMU sensors and GPS receiver. We have conducted a simulation and some field tests to evaluate the performance of this algorithm. Then we proved the performance in both post-processing program and real time program.