Performance Analysis of Multi-GNSS Precise Point Positioning

Currently, there are mainly four global navigation satellite systems (GNSS): GPS, GLONASS, Galileo, and BeiDou. GPS and GLONASS are already mature while Galileo is developing rapidly, and now the number of Galileo In-Orbit Validation (IOV) satellites has reached 18. BeiDou has provided services for the Asia Pacific region since 2012. In addition, the Japanese regional navigation and positioning system QZSS is also developing quickly. It can be predicted that the number of satellites which can be observed in the Asia Pacific region will exceed 100 in the near future. In this study, 6 stations and IGS products such as precise orbit and clock are selected for the IF (ionospheric-free) PPP to analyze the performance of multi-GNSS PPP. It can be concluded that combination of multi-GNSS combination do make contributions to the improvement of positioning accuracy compared with single-system based PPP. In addition, the authors also do some research on elevation cut-off angles in multi-GNSS PPP.