Error Analysis And Indexing Scheme Research On Strapdown Inertial Navigation System With Imu Rotating

Inertial sensors are fixed and bonded to carriers directly in strapdown inertial navigation system, which can omit the mechanical and electronic navigation platform. This kind of system with the advantages of small size,light weight and high reliability may replace platform inertial navigation system gradually. With the influence from precision of inertial sensors and working condition, the accuracy of SINS is lower than the traditional PINS. Nowadays, the technique of error rotation auto-compensation is an effective way to improve the accuracy of SINS, on condition that the inertial sensor's manufacturing precision is at the level of present technology. This thesis has researched mainly on the error rotation auto-compensation of the optical gyro SINS. The main research work includes the following three parts:(1) On the basis of the SINS, The principle of the error depressing is analysed firstly. Then discussion is given on the basic structure of the SINS with IMU rotating and the auto-compensation principle about the drift error of the inertial sensors. After that, a dynamic error model is established for the rotating SINS, the analytic expression of the system error is also derived. Finally, the thesis analyze the error effects of the various error sources in the SINS with IMU rotating, including the scale factor error, misalignment error, random drift error, dimension effect error, and so on.(2) In SINS with IMU rotating, the research on the indexing scheme is given additionally. Firstly, the compensation effects of the various rotational modes are analyzed in this thesis, and the evaluation principles of the indexing scheme are also proposed. Based on the conclusion above, the feasibility of the indexing scheme is discussed, including uniaxial two-position, uniaxial four-position and biaxial eight-sequence rotation programs. Then the advantages and disadvantages of the indexing scheme which was mentioned are compared.(3) A simulation model based on Matlab/Simulink is designed to prove the error analytical results under the rotational condition. By means of turntable experiments which are designed, it is shows that the improvement of SINS with IMU rotating. Additionally, the indexing scheme's effectiveness is testified by these experiments.Based on the theoretic analysis, system simulation and turntable experiment above, it comes to the conclusion that the drift errors of inertial sensors and other errors can be compensated effectively by the technique of error rotation auto-compensation with IMU rotating. The accuracy of INS could be greatly improved by way of the indexing scheme which is designed rationally.