Research On Initial Alignment Technology Of Land Strapdown Inertial Navigation System On Moving Base

The land strapdown inertial navigation system has very good continuity and concealment,so it is applied in many aspects.The attitude information of the carrier must be known when the strapdown inertial navigation system starts to work,so it is necessary to carry out initial alignment.The accuracy of initial alignment is the key to accurate navigation.How to carry out initial alignment in the process of carrier travel has become the focus of research,and it is of great significance to study how to make the initial alignment both accurate and fast.This paper mainly studies the following aspects:Firstly,based on the traditional coning error compensation algorithm,an improved compensation method is innovated.The traditional algorithm has the problem that increasing the number of subsamples in each compensation period will reduce the attitude update frequency.This paper starts with selecting subsamples and repeatedly selects the subsamples in the previous cycles to compensate the cone error in the current cycle.By selecting subsamples,the attitude update frequency can be consistent with the sampling frequency,This conclusion is also verified by simulation experiments.Secondly,the coarse alignment technology of strapdown inertial navigation system under the moving base is studied.With the aid of the odometer,the inertial system coarse alignment algorithm is studied.The inertial system coarse alignment algorithm converts the solution of the attitude matrix into the solution of the other three matrices.The transformed matrices all use the inertial system as the reference coordinate system.In addition,to solve the problem of insufficient use of data information in the dual-vector attitude determination algorithm,a multi-vector attitude determination algorithm is proposed.The multi-vector attitude determination algorithm utilizes the data information at multiple moments,which is conducive to the calculation of the attitude.It is applied to the coarse alignment process,and finally a simulation experiment is performed to compare the alignment effects of the two methods.The experimental results show that the stability and accuracy of the multi-vector algorithm are higher than that of the traditional method.Thirdly,the precision alignment technology of strapdown inertial navigation system under moving base is studied.Establish the filtering model of the linear Kalman filter algorithm in the case of small misalignment angles,and perform initial alignment in the case of small misalignment angles.Establish the error model under the large misalignment angle,and study the alignment effect of the nonlinear Kalman filter algorithm under the large misalignment angle,and compare the two algorithms of the unscented Kalman filter and the extended Kalman filter in the initial misalignment angle.For the alignment effect under the large misalignment angle,the experimental results show that the unscented Kalman filter algorithm has more advantages in solving the initial alignment under the large misalignment angle.In addition,the reverse navigation algorithm is also studied,and the inertial navigation data is reused.The simulation results show that the application of the inverse navigation algorithm in the alignment process can improve the initial alignment effect.Finally,in order to verify the overall alignment effect of the above algorithm in the strapdown inertial navigation system,this paper also designed an on-board experiment.The strapdown inertial navigation system is installed on the vehicle and the GPS is used to provide the longitudinal speed of the vehicle.In actual environment Check the effectiveness of the algorithm.The results of the vehicle-mounted experiment show that the algorithm designed in this paper can achieve the ideal alignment effect in the actual initial alignment.