Research On Data Acquisition And Processing Technique Of Strapdown Inertial Navigation System Based On MIMU

Strapdown Inertial Navigation System (SINS) has been a trend of inertial technique in recent years, with the rapid development of Micro-Electromechanical System (MEMS), Micro-Inertial Measure Unit (MIMU) has become the key research areas in strapdown inertial navigation field. This paper aimed at data acquisition and processing technique of the gyroscope and accelerometer in MIMU, proposed a new kind of method, and solved the problems of the existing MIMU system. Primary works are as follows:The basic theory of SINS was studied systematically, the advantages and disadvantages of three kinds of strapdown attitude algorithms including the Euler angles method, the direction cosine law and the quaternion method were analysed comparatively. Then the quaternion method's application in calculation of the strapdown attitude matrix was introduced focused.The composition program and data acquisition program of MIMU system were designed. Firstly, the construct composition and the working principle of MIMU system were described.Secondly, in view of the demands of wide dynamic measurement range and high accuracy for MIMU's data acquisition, a kind of data acquisition method which based on Automatic Gain Control (AGC) A/D Conversion was proposed, and the circuit-design of the data acquisition method was given in this paper. Finally, analysis computing and simulation experiments were used to show that this kind of method can improve dynamic measurement range of MIMU's data acquisition.Various error sources that influenced the accuracy of MIMU system were analyzed, and Micro-Inertial instrument error model, attitude error model, position and velocity error model of MIMU system were established through derivation.Kalman filter theory's primary principles and conditions of application were analyzed, then the kalman filter was designed and realized in MIMU system, after the MIMU system's state and measurement variables were modeled, simulation experiments of the kalman filter were carried out. The reasons of divergence phenomenon in conventional kalman filter were discussed, the data processing method for sovling the problems were proposed, that is adaptive kalman filter.The simulation experiments of the adaptive kalman filter were carried out, the results showed that this method can effectively improve the accuracy of MIMU system.