Design And Algorithm Research Of Magnetometer/Inertial Integrated Attitude Measurement System Based On DSP

The traditional method of attitude measurement using gyroscopes and accelerometers has shortcomings of inertial device errors accumulated over time.The geomagnetic field is the inherent resource of the earth.The geomagnetic field can be used as the reference basis for the measurement of the attitude of the supporter by the characteristics of the geomagnetic field.The magnetometer can effectively measure the geomagnetic field vector,and the magnetometer has no accumulative error and fast response speed.Therefore,the attitude measurement with magnetometer,gyroscope and accelerometer can overcome the accumulative error of inertial devices and improve the accuracy of attitude measurement.In this thesis,a magnetometer / inertial integrated attitude measurement system is designed and its algorithm is studied.The main contents include:(1)The hardware modular of the attitude measurement system is designed.It mainly includes the selection and analysis of the main components of DSP and sensor measurement unit,and designs and debugging of hardware circuit.In addition,the host computer software is programmed for the system to display and save the data.(2)The calibration algorithm of magnetometer is studied.The error of magnetometer is analyzed,and the error model of magnetometer is established.On the basis of analyzing the ellipsoid fitting algorithm based on the least square method,starting with ellipsoid fitting residual,with the aid of normal distribution mathematical tool,the data is optimized iteratively,and the rough difference is reduced,and the ellipsoid fitting algorithm is improved,and simulation experiment is designed and completed.The contrast experiment is both done before and after the improvement of the design algorithm.It is concluded that the improved algorithm is more effective in compensating magnetometer error.(3)The attitude determination function of the system is realized by complementary filtering algorithm.The contrast experiment with the traditional Picards algorithm for solving quaternion attitude calculation is designed.The experimental results show that the complementary filtering algorithm has a better suppression effect on the drift error of the attitude,and the accuracy is higher than that of the traditional Picards algorithm for solving quaternion attitude calculation.