The main aim using SINS/GPS integrated system in navigation is to improve long-term accuracy. For remote sensing application, both long-term accuracy and short-term accuracy are important. The SINS/GPS pseudo-range and pseudo-range rate integrated navigation system are studied based on the precise model of pseudorange rate in which position error is concerned in this paper. Simulation results show that the long-term position error of integrated system is within 5 meters. If the middling accuracy inertial instrument is used, the relative change of position error in the time interval of GPS measurement is centimeter level.