Research on the Influence of Assigning Weight for BDS Satellites of Different Orbits on Baseline Processing and Software Designing

GNSS relative positioning stochastic model reflects the noise level of observation data, in the process of baseline processing, reasonable stochastic model can improve the precision of calculating. Beidou navigation system (BDS) consists of three kinds of satellite: Geosynchronous Earth Orbit satellite (GEO), Medium Earth Orbit satellite (MEO) and Inclined Geosynchronous Satellite Orbit (IGSO). Due to the difference of orbits, it should be distinguished when select stochastic model for the three kinds of satellite. In this paper, the three kinds of satellite are assigned different weight based on posteriori root mean square error (RMS) of Beidou zero-difference phase observation combined with elevation angle stochastic model, and based on BDS baseline processing software, the conclusion is verified by experiment with 79.4 km baseline data of seven days. The experiment result shows that it can improve the precision and daily repeatability of BDS baseline result as the biggest, least and middle weight are assigned to IGSO, MEO and GEO respectively when processing data of BDS; the baseline result of BDS processed by the BDS baseline processing software are compared with baseline result of GPS processed by Bernese software, it shows that the difference of the two results is less than 1 cm in plane direction and less than 2.6 cm in up direction.