Abstract: With the continuous advancement of the global networking work of the BeiDou Navigation Satellite System(BDS), it already has global positioning and navigation service capabilities. According to the fact of the RTK positioning performances in the case of BDS-3 is uncertain,this paper puts forward a method to analyze the RTK positioning performance of BDS-3. In order to evaluate this,the observation data collected by the four reference stations in Shanghai on the 305th day of 2019 is divided into two cases with different baseline lengths. The single-baseline RTK positioning solution is performed. This paper analyzes in details on the accuracy improvement of the combined BDS-2 and BDS-3 through experiments. The experimental results show that compared to BDS-2 only, the combined BDS-2 and BDS-3 increases 3~6 visible satellites, which has a great improvement in the satellite space structure. For a short baseline, effectively improves the ambiguities fixing success rate from 89.3% to 92.3%, and the N, E and U components are improved by 4%, 43.23% and 35.60%, respectively. Moreover, more BDS-3 satellites can speed up the convergence of the RTK positioning solution in the case of medium and long baselines and obtain the centimeter-level positioning accuracy.

Key words: BDS-3, real-time kinematic, medium and long baseline, positioning accuracy