Research On GPS/MEMS Integrated Vehicle Attitude Determination Technology

With the rapid development of driverless technology,precise and safe driverless technology needs precise and stable vehicle motion direction parameters.Vehicle attitude angle describes the vehicle motion direction in three-dimensional space,which plays a key role in automatic navigation control.In recent years,unmanned navigation system has higher requirements for vehicle attitude,especially in the complex operation environment,the traditional Global Positioning System(GPS)attitude measurement system and Inertial Navigation System(INS)can no longer meet the application requirements.In addition,the GPS attitude measurement system has the characteristics of high accuracy and low cost,it is easy to be affected by occluded environment and low update frequency,although the inertial sensor has high short-term accuracy and good dynamic performance,it has accumulated drift error.To solve the above problems,based on the GPS attitude measurement platform,this thesis designs a vehicle attitude measurement method assisted by Microelectro Mechanical Systems(MEMS),and studies the error elimination algorithm for vehicle attitude measurement in complex environment,which improves the accuracy and stability of vehicle attitude measurement in complex environment.Firstly,in view of the instability and large error of vehicle attitude measurement results in complex environment,the error characteristics of vehicle attitude measurement in complex environment are analyzed,and the adaptive robust Kalman algorithm and MEMS assisted GPS attitude measurement algorithm are proposed to eliminate the error.An adaptive robust Kalman filter based on GPS single difference integer ambiguity is designed to eliminate the observation model error and random motion error.The algorithm of error elimination based on MEMS is studied,and the result of MEMS attitude measurement is used to assist floating-point unfixing,which improves the reliability and stability of vehicle attitude angle measurement in complex environment.Secondly,based on the extended Kalman filter,the research of GPS / MEMS combined attitude measurement technology is carried out.Firstly,the loose combined attitude measurement technology scheme is established,and the state equation is constructed by selecting the MEMS measurement attitude angle error and sensor error.Then the GPS attitude measurement result and accelerometer measurement value are used as the measurement equation to update the Kalman filter,and the loose combined attitude angle is obtained.In addition,the pseudo range double difference and pseudo range rate difference equations are derived as the measurement equations of the compact combination filter,and the MEMS and GPS noise errors are used as the state equations to estimate the optimal attitude angle of the compact combination,which improves the stability of the combined attitude measurement system.Finally,the algorithm is implemented in hardware and software,the hardware and software system architecture are designed,and the algorithm flow and program design scheme are introduced.The experimental platform is built to test the algorithm.The test results show that the GPS / MEMS combined vehicle attitude measurement technology in this thesis effectively improves the reliability and stability of vehicle attitude angle solution in the environment of straight line,turning and occlusion.