Research On Integrated Navigation System For Vehicle

With the development of Intelligent Transportation System, more and more attention has been paid to vehicle navigation and positioning technology. This thesis focuses on the key technologies of low-cost SINS/GPS/EC integrated navigation system, in order to provide an effective way to achieve high precision navigation for land vehicles.Firstly, the principles and error models of subsystems have been described in detail for improving the accuracy of the integrated navigation system. An experiment is designed to identify the constant errors, scale factor errors and installation errors of the MEMS sensors in Strap-down Inertial Navigation System (SINS). And the nonlinear two-step estimation algorithm based on ellipse hypothesis is used to compensate the error of Electrical Compass (EC). The experimental results show the effectiveness of the presented method.Due to azimuth alignment is hard to be accomplished in low-cost SINS, an initial alignment method for SINS was proposed based on coarse alignment assisted by electrical compass and the fine alignment using Kalman filtering technology. In the fine alignment process, the design of the Kalman filter and simplified Sage-Husa adaptive Kalman filter based on SINS initial alignment linear error model have been introduced, as well as the design of the adaptive extended Kalman filter and unscented Kalman filter based on the nonlinear error model. Experimental results show that the adaptive method can improve the alignment precision when the R matrix is unknown, and the nonlinear filtering methods are superior in alignment time and precision even if the azimuth error is fairly small after coarse alignment.An adaptive Federal Kalman filter has been applied in SINS/GPS/EC integrated navigation system as distributed Kalman filtering has better fault-tolerant performance than centralized filtering. A comparison of adaptive Federal Kalman filter and centralized Kalman filter has also been given by the navigation experimental results.In this thesis, a systematic study of low-cost SINS/GPS/EC integrated navigation system has been presented to provide theoretical foundation for the implementation of low cost integrated In-Vehicle Navigation System.