Fast Computation Method of Real-Time Precise Satellite Clock Errors for Combined BDS/GPS

Abstract

BeiDou Navigation Satellite System (BDS) had been officially operating since the end of 2012. It can provide service of navigation, timing, and positioning in the Asia-Pacific region. In recent years the precise positioning on BDS had been widely studied and the accuracy of BDS Precise Point Positioning (PPP) can reach centimeters. Due to the satellite clock error corrections are fixed in PPP model, the accuracy and stability of real-time satellite clock errors would directly impact the positioning accuracy of real-time PPP (RT-PPP) and are the key points of RT-PPP. In this contribution, the method of fast computation of real-time precise satellite clock errors for combined BDS/GPS was investigated. First, the estimation model of real-time satellite clock based on epoch-differenced observations was studied. Then, the extended Kalman filter (EKF) was used to estimate the satellite clock errors based on real observations which collected from multi-GNSS experiment (MGEX) stations. The accuracy of BDS/GPS real-time clock errors was also analyzed which compared with the final precise clock products. Finally, the performance of BDS/GPS RT-PPP with the real-time BDS/GPS satellite clock errors was investigated. The results showed that the real-time BDS/GPS clock corrections were comparable with the final precise clock corrections and can satisfy the accuracy requirement of RT-PPP.