Tightly coupled positioning solution for land vehicle based on UPF
                                                                             JIANG Rong1, CHEN Bai2
(1.School of Instrument Science and Engineering, Southeast University, Nanjing 210096, China;2.College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China)

Abstract: Aiming at achieving reliable, accurate and low cost vehicle positioning performance in urban environment, a tightlycoupled positioning solution was researched, which integrates the dual constellation GNSSs (i.e. GPS, BeiDou) and other low cost complementary in vehicle sensors.First, the nonlinear filtermodel was established based on a cost effective reduced inertial sensor system (RISS) and dual constellation GNSSs.Then, an improved unscented particle filter algorithm was applied to achieve the global fusion.In the implementation of fusion, a fuzzy calibration logic was introduced to adaptively adjust the noise covariance of each pseudo range measurement based on elevation angle and carrier to noise ratio.Finally, the proposed solution was evaluated through experiments. The results indicate that the proposed solution can improve the positioning performance effectively compared with the conventional particle filter, which validates the feasibility of the proposed solution.

Key words: vehicle positioning; tightly coupled; unscented particle filter（UPF）; low cost