Loosely coupled GPS/INS integration with snap to road for low-cost land vehicle navigation: EKF-STR for low-cost applications

Nowadays, the availability of the vehicle position gets more and more important. The use of the Global Positioning System (GPS) receiver has solved this problem. Nevertheless, this system could suffer from availability of the minimum number of visible satellite, especially in harsh environment. Thus, complementary system, such us Inertial Navigation System (INS) comes to help the GPS in order to guarantee the availability of the position in these environments. Nevertheless, low-cost Microelectromechanical System (MEMS) based INS integrated with the GPS has shown weak performances even in case of using Kalman filtering. To deal with this problem, this paper proposes a new approach based on loosely coupled GPS/INS integration using Extended Kalman Filter (EKF) and aided by the map matching technique Snap To Road (STR). Experimental tests of EKF aided by STR tehcnique have shown better performances than EKF alone even in harsh environment.