Densification Methods of GPS Satellite Clock Errors and Their Impact on Orbit Determination Precision of LEOs

The application of so-called precise point positioning(PPP) method has been limited by the different interval of GPS satellite clock errors provided by IGS or its analysis centres and users.In order to cope with this problem,the commonly used densification methods of GPS satellite clock errors,especially the principle of estimation of high-rate satellite clock errors using IGS ground tracking stations have been analysed and compared.Then the results obtained by different densification method including estimation method are compared with the estimated high-rate satellite clock errors by IGS.After that the satellite clock errors gained by different densification methods introduced have been used for CHAMP orbit determination(OD) employing PPP method combined with dynamic models,and the precision of them are compared as well.The results show that GPS ground tracking data can be used for estimation of high rate satellite clock errors.The precision of estimation is about 0.1 ns to 0.5 ns,which is close to the precision of IGS.The OD precision of LEOs based on PPP method using satellite clock errors obtained by estimation discussed in this paper is less than 10 cm.