Estimation of time delay of INS/GPS navigation in airborne gravity

For high accurate applications of integration of the Inertial Navigation System (INS) and the Global Positioning System (GPS) like airborne gravity, time synchronization is of great importance. In this paper, we apply an augmented Kalman filter method with a state representing the timing error between GPS and INS. The detail deduce of the augmented Kalman filter is presented. Simulation shows that almost perfect time synchronization is obtained. Tests on the estimation of time delay of the real-world data illustrates that a sufficient accuracy is achieved in integration of SDINS and DGPS.