Research On Integrated Technique Of MTi Micro Inertial Attitude Heading Reference System & GPS

Micro-inertial sensors and measurement unit are developed with MEMS technology, however, disadvantage of low precision components, poor stability and quick error accumulation affects its navigation accuracy; Using MEMS inertial system and GPS compose integrated navigation system, can overcome the disadvantage when they work independently, and improve navigation accuracy and stabilityMTi Micro Inertial Attitude Heading Reference System used by the subjec can use Kalman filter to fuse MTi output data and GPS positioning data and obtain optimal error estimate of MTi, ensure the navigation accuracy and anti-interference ability. In the subject, the following works have been done:1. Based on the working principle of MTi Micro Inertial Attitude Heading Reference System, study the independent method of attitude determination without GPS, using quaternion error equation to design Kalman filter which is based on attitude error. Using output of accelerometer to determine the movement status of MTi, when MTi is not in accelerated movement status, using attitude which is calculated by accelerometes and magnetometers as observed value so that the compensation of gyroscope drift can be implemented while carrieris is moving. Simulation has proved validity of the algorithm and analyse limitation of this algorithm2. GPS and MTi are integrated to compose a navigation system to overcome limitations of the single use of MTi. Kalman filter is adopted to fuse MTi and GPS data and open loop correction method based on concentrative Kalman filtering is chosen after careful analysis of various Kalman filter combinations. A Kalman filter that takes MTI error (platform misaligned angel, speed error, location error and error source) and GPS positioning information as state variable and observed value respectively is proposed to compensate gyro and accelerometer drift and to estimate and compensate the location error and speed error of the navigation system, realizing precision navigation. Simulation experiments are done to verify feasibility of the combination scheme which also provides a theoretical basis for afterward vehicle experimentation.3. Vehicle experimentation is conducted to analyze the performance of MTi/GPS integrated navigation system under actual conditions. Simulation is done according to the chosen combination mode using acquired MTi and GPS data. The result shows that the integration of GPS and MTi could realize high-precision navigation.