Research On Post-processing Technology Of INS/GPS Integrated Navigation Data

With the wide application of INS/GPS integrated navigation system in various fields,it is urgent to evaluate the performance of navigation devices and sensors from the aspects of security and stability.Based on higher precision reference sensor,traditional schemes will bring higher and higher economic costs.In this paper,according to the requirement of INS/GPS integrated navigation system performance evaluation,the method of theory research,system modeling,simulation experiment and actual data verification are adopted.The key technology of INS/GPS integrated navigation data post-processing system is deeply studied.The main jobs and innovations are as follows:Firstly,the thesis has a detailed analysis on INS and GPS,elaborating the part of each system,principle of positioning,mistake model and model calculating.The characteristics of each system are summarized by simulation experiments.Secondly,the most practical Kalman filter technology in INS/GPS integrated system is analyzed.Based on the continuous Kalman filter equation in linear system,the discrete Kalman filter equation for nonlinear system is deduced.The reverse fix-interval smoothing and two-way fusion method are proposed,the reverse smoother and the two-way fusion smoother are designed.Thirdly,aiming at the initial alignment stage of INS,based on the reverse iteration,an improved reverse alignment method is proposed,and more accurate estimation of the misalignment angle is obtained by reverse iteration.Simulation results show that compared with the forward alignment method,the improved reverse alignment method can use less data and obtain the same accuracy of the misalignment angle estimation in a fixed alignment time.Especially when the alignment time is not long enough,the improved reverse alignment method can effectively improve the alignment results.Fourthly,aiming at the data post-processing stage of INS/GPS integrated navigation system,the difference between forward and reverse filtering based on EKF is analyzed,the solution model of attitude,velocity and position status in reverse processing is established.The reverse filtering algorithm and the forward/backward fusion algorithm are designed.The simulation system including trajectory generator,INS simulator,GPS simulator,INS alignment module,GPS calculation module and INS/GPS integrated navigation post-processing module is designed.The proposed method is verified by simulation and actual data.Finally,aiming at the reliability of INS/GPS integrated navigation system,a fault diagnosis algorithm based on residual detection is proposed.The GPS step fault and slope fault processing module is added to the modular simulation platform.The fault diagnosis experiment is carried out.Then the proposed forward/backward fusion algorithm is applied in the case of GPS signal loss.The results show that the method can effectively suppress the error diffusion and improve the accuracy of post-processing localization.