Research On Key Technologies For Initial Alignment And Identification Of Azimuth Gyro Drift In Single-axis Rotation Strapdowm Inertial Navigation System

Rotational modulation technology is becoming a research topic in terms of the strapdown inertial navigation system(SINS).In this paper,the research is about the development on the single-axis rotary SINS based on fiber optic gyroscope.Some key techniques of the single-axis rotary SINS,such as the auto-compensation techniques of the single-axis rotary SINS,initial alignment method of SINS,the identification method of gyro drift in rotation axis,are studied in theoretical and engineering aspects in this paper.Eventually,the actual principle prototype is built and tested.The major contents of this paper are as follows:1.The structure and principle of the single-axis rotary SINS are analyzed in this dissertation and the error equation of the single-axis rotary SINS is derived based on it.Meanwhile,the principle of the error compensation of the single-axis rotary SINS is studied by analyzing error transfer characteristics of sensors in the single-axis rotary SINS.2.The initial alignment method of the single-axis rotary SINS is investigated in this paper.Considering the dynamic characteristics of the working environment,the Solidification method for coarse alignment and the H∞ filter for precision alignment based on speed matching.Mathematical simulations and actual system verification experiments are carried out,and the results show that the proposed method can accurately improve the precision of the initial alignment in the single-axis rotary SINS,which can further increase the positioning accuracy of the inertial navigation system.3.The accurate identification method of gyro drift in rotation axis is analyzed in this dissertation.Since the gyro drift in rotation axis can not be modulated in the single-axis rotary SINS,and it will cause the accumulated position error over time.In order to improve the precision of long time navigation for the single-axis rotary SINS,an accurate method using guassian processes regression to calibrate the azimuth gyro drift is proposed.Mathematical simulations are carried out,and the results show that the method proposed can accurately identify the azimuth gyro constant drift of the single-axis rotary SINS,and the positioning accuracy of the single-axis rotary SINS is greatly improved after error compensation.4.A series of related navigation experiments based on the real single-axis rotary SINS are conducted,including static experiments,swing experiments,vehicle experiments and so on.The feasibility of the schemes is verified.