Abstract: Clock synchronization technology is an important research content based on IGPS base-station networks of target positioning.An adaptive discrete-time Kalman filtering method combined with IGPS base-station clocks is proposed.The algorithm is carried out by using the property that the measurement innovation sequence is piecewise stationary inside an estimation window.The algorithm also overcomes the traditional Kalman filtering process which excessively relies on the correctness of the mathematical and stastical models.Using this algorithm,the relative phase offsets and clock skews among the clocks of IGPS base-stations can be corrected and converted.Also,the best fit line over the observations on line can be found,and the covariance matrices of the process and measurement noises are estimated.Simulation results show that the proposed algorithm can improve the accuracy of clock synchronization among IGPS base-stations and the synchronization accuracy can reach the microsecond order of magnitude.