Abstract:In precise point positioning, high-precision floating ambiguity is important to ensure that integer carrier phase ambiguities are resolved reliably. However, a convergence time of several tens of minutes is required to obtain high-precision floating ambiguity. In this paper, BDS/GPS/GLONASS combined PPP are carried out to accelerate convergence, and then we use the inter phase clock method to realize the GPS PPP ambiguity fixing. Six MGEX stations are used for the kinematic PPP test. The results show that, first, compared with ambiguity-floating PPP, ambiguity-fixed PPP obtains better positioning accuracy, and the BDS/GPS/GLONASS ambiguity-fixed PPP further improves positioning accuracy. Second, the TTFF (time to first fixed) for GPS ambiguity-fixed is 46.1 min, while only 25.8 min for BDS/GPS/GLONASS ambiguity-fixed, which reduces 44.0%. Third, the ambiguities fixed rate raise from 78.6% to 87.4%, improving nearly nine percentage points.