Abstract:Using GFZ and WHU precise products, we compare and analyze the accuracy of GNSS precise products. We then select 18 MGEX stations distributed in the eastern hemisphere for BDS/GPS/GLONASS/Galileo PPP experiments based on WHU precise products and investigate the PPP performances of the BDS B1C/B2a and B1I/B3I ionosphere-free combinations. The results show that the accuracy of GNSS orbit products is at the cm level, and the STD of GNSS precise clock is better than 0.1 ns. We find that BDS-3 satellite clock accuracy is significantly improved compared to BDS-2. The PPP experiments show that the PPP performance of BDS is the best in the Asia-Pacific region, and in non-Asia-Pacific region, GPS positioning accuracy is better. The convergence times of BDS static and kinematic PPP are 50 mins and 78 mins, which are lightly slower than that of GPS and Galileo, and better than that of GLONASS. The comparison shows that the PPP performance of the B1C/B2a and B1I/B3I dual-frequency combinations is basically comparable.