Study On The Method Of INS/GNSS Integrated Navigation Robust Adaptive Kalman Filtering

The gradual development and improvement of Kalman filtering provides the theoretical basis and mathematical tools for the INS/GNSS integrated navigation.INS and GNSS have the characteristics of strong complementarity,so that,INS/GNSS integrated navigation has become one of the navigation systems which can realize continuity,high reliability and high precision.INS/GNSS integrated navigation system has been widely used in surveying and mapping field such as vehicle mobile mapping,airborne photogrammetry,and other fields like military field and civilian areas.Aiming at the increasingly requirement of high precision and high reliability for INS/GNSS integrated navigation system,considering the problems that the motion complexity of the carrier usually leads to the noise statistic characteristic being not given accurately in the process of movement,and the filtering result is susceptible to the gross error of observation,the paper focuses on the study of Kalman filtering.Firstly,a summary is made based on the working principle,Kalman filtering state equation,observation equation and its solution process of loose integration and tight integration.In addition,Nonlinear Kalman filtering model is deduced and analyzed.The simulation results show that velocity and position accuracy of UKF are better than EKF without considering the computer memory and real-time.What's more,the robust adaptive algorithm is constructed to adjustment of the weights of observations adaptively.The simulation results show that the algorithm can effectively suppress the influence of gross errors on navigation results.The integrated navigation system based on Kalman filtering is realized and verified through vehicle experiment.The experimental results show that the tight integration is better in the navigation precision than the loose integration.However,when the number of visible satellites is small and the observation conditions are not ideal,the error of the tight integration navigation will become larger.To a certain extent,the fluctuation of error can be controlled when tight integration is adopted to the robust adaptive method.