Research On GPS/INS Integrated Navigation Based On The Time Differenced Carrier Phase Velocity Estimation Approach

With the development of information age, navigation and positioning technology is not only increasingly widespread utilized in the field of military and civilian, such as aviation, spaceflight, weapon guidance, intelligent vehicle, but also the navigation system with higher precision and reliability is demanded. Through synthesizing the advantages of GPS and INS, the GPS/INS integrated navigation realizes the performance with high precision, good stability and complete function. This paper mainly focuses on GPS time differenced carrier phase velocity estimation approach, based on researching and resolving the key technologys in GPS/INS integrated navigation, aiding INS with the high precision velocity derived from GPS time differenced carrier phase and kinematic pseudorange single point positioning. The main work and contributions are summarized as follows:(1) The updating algorithms of attitude, velocity and position in SINS are deduced, and the error model is analyzed and established. Through the field data of GPS/INS, the characteristic of INS that error accumulates over time and navigation precision declines gradually is analyzed quantitively. Studying the method aiding INS with high precision velocity derived from GPS time differenced carrier phase approach, the experiment result indicates the error accumulation of INS is restrained effectively, and the navigation precision is improved.(2) The research of GPS time differenced carrier phase velocity estimation approach is improved. Based on comprehensive analysis of the vehicle’s motion state, and with the reliable data is of cycle slip detected, discusses the impact of satellite clock error, relativistic effect, ionospheric delay, tropospheric delay and earth’s rotation effect on the velocity estimation of time differenced carrier phase. Comprehensively evaluates the velocity estimation precision of time differenced carrier phase in static and dynamic, the research method and result is of a certain reference value.(3) The relationship of numbers of visible satellites and elevation with GDOP in GPS kinematic pseudorange single point positioning is researched comprehensively and systematically. Through comparing with RTK positioning result ambiguity fixed, the precision of GPS kinematic pseudorange single point positioning is analyzed, and draws the conclusion that the reduce of visible satellites has a consistent influence on GPS positioning within a short time. The method detecting and correcting the positioning blunder with velocity error based on the high accuracy velocity derived from GPS time differenced carrier phase is proposed, and the validity is proved with example.(4) The integrated mode, filtering algorithm and system model of GPS/INS integrated navigation is analyzed and established, and aiding INS with the result of GPS time differenced carrier phase and kinematic pseudorange single point positioning is implemented. Based on analyzing the navigation results that integrated with velocity, position and the two together, concludes the three integrated modes can make the drawback of INS that error accumulates over time restrained. Aiding INS with GPS time differenced carrier phase and kinematic pseudorange single point positioning simultaneously is a more effective and practical way of navigation relatively.