Abstract: A modified structure mode is presented for the integrated navigation system to solve the positioning precision problem of the GPS/SINS integrated navigation system in high dynamic environment.A block of time synchronizing in high dynamic environment is added to the structure to decrease synchronization error of the system measurement data,in which the synchronization error due to the drifting output period of the SINS's satellite-station range is considered.The drift variable is brought into the state vector of Kalman filter,and its estimation value is used to calculate the synchronous time difference, time tag difference and extrapolated value of the satellite-station range.The measuring equations including the drift are listed in the Kalman filter model.Finally,the control parameters are selected and a rectification algorithm of closed-loop filtering in high dynamic environment is presented.Simulation results prove the efficiency of the presented method.