With the development of the Australian Analysis Centre Software, preliminary results have been obtained with regard to the precise satellite clock estimation for GPS, GLONASS, BeiDou and Galileo. The software employs the traditional dual- frequency ionosphere-free linear combination to eliminate the impact from the ionosphere. A pivot receiver’s clock is constrained to zero to remove the rank- deficiency in the normal equation. By fixing the satellite and station positions, the state vector, which consists of receiver clocks, zenith troposphere wet delay, satellite clocks and the float ambiguities, is estimated using the Kalman filter, with proper settings of the process noise. To evaluate the satellite clock solution, firstly, a global IGS network stations are selected. GPS and GLONASS clock products are generated and then compared against the IGS final clock product. Then, another MGEX network is chosen and the satellite clocks for the four constellations are estimated together and analysed using the MGEX clock product. The results indicate that the generated clock products are at the similar level of accuracy as IGS and MGEX clock products.