Kinematic Wide Area Differential Corrections for BeiDou Regional System Basing on Two-Way Time Synchronization

Abstract

Real-time wide area differential corrections are provided to BeiDou authorized users to satisfy the need of high-accuracy navigation service. The algorithm of wide area differential corrections are studied based on independent two-way time synchronization system and the performance of two kinds of differential modes with one-dimensional (also the equivalent satellite clock correction introduced in BeiDou ICD file) or four-dimensional correction are comparatively analyzed. The results show that for the current one-dimensional mode, the correction accuracy will decrease when the orbital errors are large, especially for the situations such as quickly orbit determination recovery after satellite failure or maneuver. While for the four-dimensional mode, the stability and precision of the separation of ephemeris and satellite clock parameters are seriously limited by the regional monitoring network. Applying the two-way time synchronization observations, the high-precision separation of orbital and satellite clock errors is realized with kinematic method, and with actual observations, the processing results show that user differential range error may be minimized to decimeter level and the positioning accuracy is also improved by 40 % in the area lacked monitor stations. The four-dimensional mode may process in real-time and once be applied in BeiDou Wide Area Differential Augmentation System, the accuracy, continuity and availability of the system will all be improved.