GPS/BDS One-Step Combined Precise Orbit Determination Based on Double-Differenced Mode

In order to improve the precision of BDS precise ephemeris, GPS/BDS one-step combined precise orbit determination based on double-differenced mode was testified in this contribution. And double-differenced data was not formed between GPS and BDS, which eliminates the effect of inter system bias (ISB) on the precision of BeiDou precise orbit. Not only GPS and BDS orbit parameters are estimated, earth rotation parameter (ERP) and station coordinates are also estimated. Data of 114 tracking stations from MGEX are processed. The analysis shows that: Compared with IGS final orbit, the precision of GPS orbit is 5 cm, the precision of Xp, Yp, length of day (LOD) is 0.06, 0.10 mas, 21.6 μs. Validating the BDS orbit using SLR observation shows that the radial precision of BDS IGSO and MEO satellites is better than 6 cm, while that of GEO satellite is about 0.37 m.