Abstract: In the process of satellite navigation and positioning, when the signal quality is poor, the auxiliary positioning algorithm can use more observed satellite data for redundant calculation, supplement the missing signal time and obtain the positioning results. The Beidou Satellite Navigation System (BDS) independently developed by China adopts a hybrid satellite constellation, including a class of Geostationary Earth Orbit (GEO) satellites, which has the advantages of 24 h visibility, high orbit, large coverage and strong signal power. This paper analyzes the auxiliary positioning algorithm and the performance difference of the algorithm when only GEO satellites can be received in special cases. The conclusion shows that without the assistance of prior information such as elevation, the direct use of five GEO satellites can also obtain a certain positioning accuracy guarantee.