Abstract:We perform multi-GNSS precise point positioning(PPP) testing on MGEX stations based on the ISC products released by the iGMAS Product Integration and Service Center(ISC), the GBM products released by the Helmholtz-Centre Potsdam-German Research Centre for Geosciences(GFZ), and the GBM-300 s products based on re-sampling of GBM clock products. This paper analyzes the positioning accuracy, convergence rate, ZTD accuracy and station clock accuracy of 15 MGEX stations around the world from January 1 to January 15, 2018. The experimental results show that the 3D positioning accuracy and convergence rates of Beidou PPP based on the ISC products are better than GBM products for 0.89mm and 24 min; the ZTD accuracy and station clock accuracy of the Beidou PPP based on the ISC products are better than GBM products for 0.3 mm and 0.02 ns; the difference between the ZTD accuracy and the station clock of the GPS, GLONASS, Galileo PPP and the four system combination PPP based on the ISC products, as compared with that based on the GBM products is less than 1.5 mm and 0.05 ns. However, the positioning accuracy of the PPP based on ISC products is lower than that based on GBM products for 2 to 3 mm in the Up direction and the convergence rate of the PPP based on ISC products is slower than that of GBM products for 5 to 20 min. This paper analyzes the accuracy and service reliability of iGMAS products, and gives suggestions for the improvement of iGMAS product performance.