The Global Positioning System (GPS) has become very popular in designing navigation systems. But GPS cannot provide the precise and real-time positioning information when its signal is blocked. In order to solve this problem, another independent navigation system, INS, shall be adopted and the GPS/INS integrated system should be developed to provide the positioning information during the GPS outage.
Due to the existence of bias error in using the inertial sensors, the navigation error with INS grows bigger and bigger with time. In the GPS/INS integrated system, the bias errors are estimated by using GPS signal. Once calibrated, the INS can provide positioning information during the GPS outage. Accordingly, the two navigation systems can compensate with each other, and the integration enhances the performance of the navigation system significantly.
In this thesis, we shall develop the 2-D GPS/INS integrated system by using the constraint that the vehicle is moving on the plane. When GPS signal is unavailable, the notion of virtual measurement is adopted to provide some positioning information through the consideration of the constraints. It is further discovered that the information of the speed of the vehicle, which may be obtain by measuring the rotation rate of the wheel, is essential to generate good virtual measurement. The performance of the algorithm is verified by experimental result. Moreover, 3-D GPS/INS integrated navigation system is also developed and its result is compared with the 2-D GPS/INS system. It is seen that the 2-D GPS/INS system is adequate in vehicle navigation in our experiment setup.