Precise Point Positioning with Multi-constellation Satellite Systems: BeiDou、Galileo、GLONASS、GPS

With the appearance of China's BeiDou system and EU's Galileo system and the restoration and improvement of Russia's GLONASS navigation system, the single GPS navigation satellite system has been gradually developed into multi-GNSS (multi-constellation global navigation satellite systems). Multi-GNSS with precise positioning will become the development trend of GNSS precise positioning in the future. Using the observation data collected by PPP (precise point positioning), which integrates the four major satellite navigation systems of GPS、 GLONASS、 BeiDou and Galileo, this paper conducts a preliminary study and analyzes the positioning performance of multi-system PPP. According to the experiment, in areas where single system observation geometrical configuration is unsatisfactory, multi-system integration can greatly improve the positioning accuracy and convergence rate of PPP. The convergence rate of multi-constellation PPP is 30% to 50% higher than that of single GPS, and the positioning accuracy can also be improved 10% to 30%, especially in terms of elevation direction. Besides, under observation circumstance where the end elevation angle of satellite is larger than 30 degrees, single GPS fails to carry out continuous positioning due to lack of visible satellites, while multi-constellation PPP can still get positioning results, with relatively high accuracy in horizontal direction especially