Design Of High-precision Attitude Determination System Based On MEMS Sensor

Attitude determination system based on MEMS is a new inertial measurement equipment,which can provide real-time vehicle roll angle, pitch angle, and yaw angle information. It has good portability advantages on its low cost, small size, low power consumption and portability. Therefore, it was widely used in every aspect of life and production in recent years. Compared with the attitude detection system based on optical fiber sensors its precision is low, so it is hard to be used in ships and aircraft. However, it's hard to improve accuracy by improving the MEMS sensors' devices. Therefore, improve the accuracy through the software to compensation the error is an urgent problem to be solved. In addition to ensure the portability of the system though extending the data communication function is also a problem worthy of attention.Summarizes the attitude determination system from error model and error compensation of the MEMS devices, attitude calculation algorithm, the hardware circuit and software programs. The main tasks are as follows:Firstly, the research goal and the significance of the attitude determination system is introduced, the international development status and the key techniques need to solved is analyzed; According to system requirements, the MEMS devices were selected,and a digital three-axis gyro instrument FXAS21002C and six-axis sensor FXOS8700CQ were choice to provide information to attitude; for reducing the MEMS gyroscope's random errors FIR filter is used; sensor installation errors, and standard degrees factor errors model is established for completing the sensor's calibration and correction; In order to realize temperature compensation of the MEMS gyroscope, artificial fish algorithm is used; the three error parameters is gotten through MATLAB software.Secondly, the overall design scheme of the attitude updating algorithms was proposed.Comparing Quaternion algorithm and Rotation Vector algorithm, Quaternion algorithm is better in attitude solutions. A initial alignment algorithm was designed to provide quaternion for system. A multi-sensors fusion extended Kalman filter algorithm was designed to advance dynamic capability and reduce integrating error caused by quaternion based on geomagnetic field sensor and accelerometer.Thirdly, the attitude detection system hardware platform design scheme is put forward,the power management circuits is designed for provideing electrical energy to the system.Kinetis60 single-chip microcomputer is used as the core controller, converted and calculated the attitude information collected by the MEMS sensor. In addition, the SD card storage circuit is designed based on SDCH module internal integration in MCU; the WI-FI module is completed based on TCP/IP protocol; the fuction of sending data between GSM module and MCU is realized by using UART communication mode; and the LCD display is realized based on simulation SPI.Finally, the overall process of software program in the MCU is designed, the device driver and algorithmic program of MCU is compeleted, combines hardware platform and algorithm, the whole attitude measurement of the vehicle's roll, piching, and yaw angle is realized. The system's performance is tested through a set of high dynamic experiment and static esperiment on turntable, the experimental results show that the roll angle and pitching angle's precision of the MEMS attitude detection system is ±0.3°, the yaw Angle precision is±1°, and it has a good real-time performance,the carrier's attitude can be acquired and displayed in real time.