Attitude Measurement Using Combination of Magnetoresistive Sensors Based on Improved Zero Crossings Method

The accurate attitude measurement of guided projectile is the basis for realizing the precision guidance and control. As the single inertial attitude measurement method under high-g and high-speed environment causes error accumulation, this paper proposes an attitude measurement method using combination of magnetoresistive (MR) sensors based on improved zero crossings method. Firstly, magnetoresistance attitude measurement unit is designed and then the mathematical relationships between the ratio of zero crossings points of MR sensors' output signal and magnetic elevation angle is deducted. After this, the least squares zero crossings detection method based on cubic fitting function is designed. Finally, simulation experiment of attitude determination of geomagnetism is carried out to verify the effectiveness of the proposed method. The results show that compared with the traditional method, the proposed attitude measurement method having an attitude angle error of ±0.15°. Further it can obtain four groups of attitude angles in each rotation period, which provides a theoretical support for engineering application.