INS/GPS Tightly Coupled Approach Using an INS Error Predictor

In this paper, the tightly coupled INS/GPS integration system using an INS error predictor is proposed for improving the filter estimation performance when fewer than four satellites are tracked. The suggested error predictor stores the estimated position error in case of tracking above four satellites and calculates the initial error components for prediction of Schuler position error when fewer than four satellites are tracked. Using the estimated initial values, the position error is predicted and then it is considered as the additional measurement of the INS/GPS integration filter. To analyze the performance improvement of the tightly INS/GPS integration system using the predictor, simulation and real van test have been carried out. The results show that the INS error predictor 48 ION GNSS 18th International Technical Meeting of the Satellite Division, 13-16 September 2005, Long Beach, CA provides a reasonable solution for resolving the blockage of the satellite signals.