Abstract：An analysis of influence from the uncorrected satellite orbit errors on the GPS/VRS network based positioning is carried out. A precise realtime method for using the IGS ultra rapid products (IGU) and the GPS broadcast ephemeris to calculate the VRS orbit corrections is presented which is suited for the realtime correction of precise orbit of VRS in GPS/VRS reference station network based positioning. Test data acquired from both the SGRSN (Sichuan GPS Reference Station Network) and SCIGN (Southern California integrated GPS network) are used to evaluate the performance of the modeling techniques. The new method is proved to be more precise and reliable as compared with the existing conventional networkbased orbit error interpolation method. It is shown that 0.004×10 -6
relative accuracy is reached, i.e. the influence from the orbit bias for the RTK positioning within 100km area can be of submillimeter level.
