Reduced-dynamic EKF-based GPS+BDS real-time orbit determination

Abstract

Global navigation satellite system (GNSS) is of significance for orbit determination of Low Earth Orbit Satellites. Due to relatively low accuracy of code observations and high kinematic challenges, the accuracy of orbit determination by using GNSS will be limited. With the combination of the emerging constellations BDS and the modernization of GPS, the number of satellites available for users is increased. In this contribution, a modified reduced-dynamic EKF-based GPS+BDS combined model is proposed to improve accuracy of orbit determination. The proposed method uses dynamic model of orbit and EKF algorithm to smooth the GNSS positioning results. Meanwhile, this method also uses the GPS+BDS combined model to further improve the GNSS positioning accuracy. The proposed method is tested by simulated date by STK software. The simulated results show that positioning accuracy of the proposed algorithm improves almost by 45% compared with traditional algorithm. Additionally, the proposed algorithm has more robustness than the traditional algorithm.