Research On Alignment Technology Of Marine Strapdown Inertial Navigation System At Quay

Inertial navigation system is a system completely dependent on its own,and its principle is to use the information output from the inertial devices of the system to solve the demands of navigation information,including position and posture.Because it is not affected by the outside world,it is not easily detected and is more suitable for modern military applications.With the rapid development of domestic fiber inertial navigation and laser inertial navigation,more and more SINS have been successfully applied to ship navigation.Since the navigation of inertial navigation system only depends on itself,it will cause errors during the movement of the carrier,which includes the initial alignment error.Therefore,the main direction of this paper is the initial alignment of SINS in a complex environment,and the initial alignment includes coarse alignment and fine alignment.The alignment of the two were optimized to reduce the errors of SINS navigation.The paper introduces the main background of the research and the problems to be solved,and then focuses on the basic knowledge and solving principle of SINS.As the attitude is the most important parameter in the inertial navigation,its update algorithm is very important.Therefore,the article introduces the basic knowledge of the quaternion used to describe the attitude and the output form of the angular increment according to the laser inertial navigation,and the detailed derivation of the Picards solving method of attitude updating.At the same time,navigation of inertial navigation system will be interfered by itself and external errors.In this paper,the error equations of inertial navigation system are given,and the influence of three main error sources on the subsequent navigation of inertial navigation system is simulated,which proves the necessity of the research to a certain extent.In this paper,the coarse alignment used by the ship's strapdown inertial navigation system is studied.The analytical coarse alignment method,the inertial system coarse alignment method and the optimal quaternion coarse alignment method are compared and analyzed.The principles of alignment of the above method are deduced,and the simulations are performed under the conditions of static pedestal and oscillating and triaxial oscillating motion.The wavelet threshold denoising is introduced to overcome the shortcomings of the optimal quaternion coarse alignment method.By analyzing the observability of the strapdown inertial navigation system,it is proved theoretically that the swing can improve the observability of the system.At the same time,according to the unobservable state quantities of the system,the best observable subsystem is determined through the above theory,and the result is performed.The results of the simulations show that the accuracy of the dimensionality reduction is basically the same as the fulldimension accuracy.The Kalman filtering process requires accurate modeling and accurate noise statistics.If the above conditions are not met,it is easy to diverge This paper makes an in-depth study of the theory of adaptive Kalman and carries out a detailed understanding of the analysis and simulations.For the problem of low observability of gyro drift,the relationship between misalignment angle and gyro drift estimation was simulated and analyzed,and the alignment scheme measured by speed was finally determined.At the same time,according to the current development,the simulation analysis was performed on the alignment scheme measured by the speed plus attitude.The feasibility of the alignment scheme is proved by the turntable experiment and the static pedestal experimental data,and the alignment accuracy is high.