Research On Performance Enhancement Of SINS/GPS Integrated Navigation Systems

The navigation technology is wildly employed in the military, civil, and commercial fields. Thus it is important to improve the accuracy and reliability of the navigation systems in practical applications. The GPS/SINS integrated navigation is an outstanding resolution because of the complementarity. Based on the GPS/SINS integrated navigation systems, methods of enhancing the reability and accuracy of the systems have been studied by means of involving certain external information and modifying the information fusion algorithms.Usually, sensors utilized in the navigation systems have different sampling rates. Hence, a novel data fusion strategy in the federated Kalman filtering is proposed to tailor the algorithm to the multirate systems. This new algorithm is proved equivalent to the centralized filtering method. Basing on this mothed, an adaptive discentralized filtering approach is presented to obtain more accurate navigation solutions with the model uncertainty or soft fault. Moreover, this filter maintains the discentralized structure, with which it can surport fault isolution and reconfiguration. In order to evaluate and compare with the work in the following chapters, the performace of our GPS/SINS integrated navigation system is studied by numerical simulations.To increase the degree of observability of the GPS/SINS integrated navigation system, a multi-antenna GPS attitude determination method is first studied. A multi-antenna configuration scheme is presented, and the principles of the GPS differential carrier phase measurement are expatiated. Two direct attitude error correction methods using base-line measurements are proposed and compared with the indirect Euler angle error correction and quaternion error correction methods. Numerical simulation results show that these two methods are as accurate as the quaternion error correction approach, and both outperform the Euler angle error correction method. Furthermore, with our methods, the two base-lines can work asynchronously, and the computational burden is not increased.Next, the polarized light and geomagnetism aided navigation methods are proposed. The models of the polarized light measurements with regard to the attitude errors are presented. The principles of the polarized light aided attitude determination approaches and the conditions, under which the polarized light modules can be...