Orbit Determination For Single Navigation Satellite Compass-M1 Under Time Synchronization Among Stations

This paper discusses some problems about using observation data of regional tracking stations to perform orbit determination of COMPASS-M1. Considering the impact of clock behavior is the important factors of precision orbit determination, five stations arranged in china have been tracking with the frequency signal of external high-performance atomic clock, each station achieve time synchronization using Two-way Satellite Time and Frequency Transfer (TWSTFT) of National Time Service Center, Chinese Academy of Science. For orbit determination of single navigation satellite, the difference arithmetic to eliminate the clock behavior which is used in GNSS data processing can't be employed, it is necessary to develop a new strategy for orbit determination. Considering the property of clock behavior in the satellite, characterized by quadratic polynomial fit, the pseudo-range is equal to range if the main part of clock behavior seemed as range bias which characterized as quadratic polynomial. Together with orbit determination, the range bias is estimated (three parameters: constant term, linear term, quadratic term). According to the above-mentioned method. pseudo-range smoothed by carrier phase data is used to perform orbit determination. The accuracy of orbit determination is evaluated by residuals, orbit overlap and SLR residuals. It indicates that the accuracy in radial and position are better than 1m and 10m respectively.