As is true of GPS, multipath disturbance is a limiting factor for further improvements in BDS high precision positioning applications. We investigate the characteristics of multipath errors and multipath mitigation for BDS geostationary earth orbit, inclined geosynchronous orbit and medium earth orbit satellites according to their orbital repeat periods. We argue that multipath errors can be mitigated using models extracted from a previous period since there is a strong agreement correlation in the multipath errors between subsequent periods. A multipath mitigation method, which is based on observation domain filtering and considers the repeat period of every satellite independently, was applied. The application of the proposed method shows that BDS positioning precision was improved by about 56, 48, and 48 % to 1.90, 1.28, and 4.37 mm in the north, east, and up components. After resolving BDS carrier phase multipath error, the positioning precision of the combined GPS&BDS with multipath correction reached to 0.95, 0.92, and 2.31 mm in the north, east, and up components that were more precise than either the GPS or BDS system alone. The more accurate and reliable precision obtained from the combined system after applying multipath mitigation method, would greatly contribute to high-performance precision deformation monitoring and seismological studies.