Research On SINS/GPS Integrated Navigation System For Space Maneuvering Platform

Strap-down Inertial Navigation System (SINS),Global Positioning System (GPS) and Star Sensor Integrated Navigation System (SSINS) is a modern navigation system integrated with various advantages such as autonomy of SINS,high precision of GPS and accumulative-attitude-error-free of Star Sensor.SINS/GPS Integrated Navigation System,featuring characteristics of higher navigation precision,higher reliability,miniaturization,is an important scheme aiming at high autonomy and high navigation precision,while the combined scheme of Gyroscope/Star-Sensor Joint-Attitude determination is idealistic for its high precision in attitude determination.SINS/GPS closely-combined Navigation System based on pseudo-distance and pseudo-velocity has better navigation precision,robustness,and noise-resilience than its counterpart based on velocity and position.The major research works of this paper consist of:Operation principles of the Strap-down Inertial Navigation System are analyzed and the mechanics arrangement and error analysis of SINS in the ground-fixed frame are discussed. Trajectory modeling system,gyroscope and accelerometer simulation systems are established based on principle analysis. SINS simulation platform is also built utilizing MATLAB/Simulink,and simulation of SINS under conditions of different initial alignment accuracy are conducted.The paper also carries out research on Closely-combined Navigation System. Using STK satellite simulation software to build up GPS satellite constellations, by visible-stars recognizing and calculating factors of geometry precision for satellite to point out the best navigation constellations,the navigation tasks for space mobile platform under both dynamic and static conditions are accomplished. It is verified via comparison between SINS and SINS/GPS closely-combined Navigation System that the SINS/GPS combined navigation system can effectively improve navigation precision to meet the requirements of navigation.Focusing at the deficiencies of SINS/GPS combined navigation system such as low course accuracy and slow convergence rates of errors,the paper presented a combined attitude determining method using SINS's gyroscope and star sensor. By designing the extended kalman filter algorithm, the advantages of star sensor and gyroscope can be fully utilized to meet the high precision requirements of spacecraft attitude determining system.