Research On Technology Of Vehicle Based On Initial Alignment Of Strapdown Inertial Navigation

Initial alignment technology is a key technology to be completed before the strapdown inertial navigation system(SINS), and its accuracy affects the accuracy of the navigation system. In recent years, alignment technology has been an important development direction of inertial technology. The initial alignment is to determine the initial time of vehicle navigation attitude matrix. The vehicle need to be realigned due to the body’s swinging, vehicle navigation error accumulated to a certain extent or software running error etal. from external interference during driving. The alignment of the vehicle in the running process can be realized by filtering technology with GPS and Doppler log information etal.. The aim of initial alignment is to establish the initial time mathematics platform as quickly and accurately as possible.From the vehicle SINS initial alignment on the basis of the actual needs, first of all the SINS of common coordinate classification system and direction cosine matrix solution construction process are introduced in this paper. The process of initial alignment was described, the model of pointing error was established, and the SINS initial alignment error propagation equation of the Euler angle representation was explained. Secondly, the static base initial alignment error is analyzed and the coarse alignment process in six different analytical method and inertial system method to construct the strapdown matrix transformation,comparative analysis that the method applied to the environmental conditions for vehicle coarse alignment environment using inertial coarse alignment method accord with the practical application. According to the filtering algorithm and the fine alignment principle, this paper analyzed the application of KF and PF two kinds of filter alignments in precision alignment,and pointed out their advantages and disadvantages. Finally, the range lost alignment alignment model and unscented Kalman filter algorithm research angle on vehicle, in order to improve the precision of initial alignment, combined the strong tracking filter with unscent Kalman filter, less dissipation factor was introduced to real-time prediction covariance matrix,UT transformation which by estimated of the current state of the system value and construct the sample point.Initial alignment simulation environment was build, this paper to simulate coarse alignment and precise alignment filtering algorithm. Reduce the dimension of filter and mixed filter use can improve the performance of alignment had summed up by a large number of environments. The simulation results show that the improved UKF filtering algorithm in dealing with vehicle range initial makes the stable alignment accuracy error reache 0.07, the alignment precision and alignment time are both improved.