Abstract: To study the mathematical modeling of MIMU/GPS integrated navigation error equations,a new equation is established by taking inertial error coefficients as the states vectors instead of MIMU measurement errors.To study the data synchronization problem of MIMU/GPS integrated navigation systems,a new data synchronization method for GPS measurement data delay is proposed.In the proposed method,MIMU states and GPS states are fused in the reality GPS sample-time,and then the results are propagated from the reality GPS sample-time to the current sample-time using the Kalman filter propagation matrix.In the end,the final states are used to initialize MIMU states for next time’s navigation.Simulation results show that the new integrated navigation model has high accuracy and the new data synchronization method is effective.