Abstract:Through the analysis of GPS satellite clock noise and the research on estimation and prediction of satellite clock error by Kalman filter the differences of accuracy among different style of clock are quantitatively revealed. Meanwhile, combined with satellite clock stability, follow conclusions can be drawn.The stability and precision of GPS Block IIR-M Rb clock is better than those of Block IIR Rb clock and stability and precision of GPS Block IIR Rb clock is better than that of Block IIA Rb clock. Compared with Rb clock, Cs clock’s stability and precision is worse by 2-3 times. Thus, some suggestion can be offered as follows. Real time state monitoring of satellite atomic clock and clock error estimation can be achieved by Kalman filter considering stochastic model of satellite clock noise, and Kalman filter has some advantages in short time prediction of satellite clock error, average prediction RMS of Rb clock is 1.90 ns, which is superior to least square algorithms.