Abstract：This paper evaluates the accuracy of GNSS navigation positioning system. The precise ephemeris and clock bias of gbm are a true reference to contrast and analyze the orbit and clock error, which is used to count spatial signal ranging error of GPS, BDS, Galileo and GLONASS navigation files from February 1 to February 28 of 2017. The experimental results show that the accuracy of GPS orbit to the neck, tangential, normal, clock difference and SISRE is 1 m, 0.4 m, 0.8 m, 2 ns, 0.4 m respectively. Different types of BDS tracks show larger differences; the Galileo is 0.3 m, 0.3 m, 0.2 m, 3 ns and 1 m; the GLONASS is 0.4 m, 1.0 m, 0.4 m, 7 ns and 2 m.
