航姿系统矢量传感器非对准误差及其校正

航姿参考系统中三轴磁强计与三轴加速度计常采用椭球拟合法进行误差校正与补偿,其缺点是校正后不同传感器之间以及传感器坐标系与载体坐标系之间往往还存在非对准误差.由定量分析得知此类非对准误差所引起的航姿参考系统航向角误差具有常值误差与半圆罗差之和的形式.利用地磁矢量与重力矢量的点积为常数这一性质,并结合三维旋转矩阵的小角度近似表达式,对椭球拟合法校正后的传感器非对准误差进行了补偿,在不同磁干扰条件下均可使校正效果得到改善,航向剩余误差(均方根)平均减小30%以上.

Inter-triad Misalignment of Vector Field Sensors in Attitude and Heading Reference Systems and Its Calibration

Ellipsoid fitting method is frequently used to eliminate the error of tri-axial magnetometer and accelerometer in attitude and heading reference system(AHRS).But the defect is that it cannot resolve the inter-triad misalignment between different sensors,as well as between the sensor frame and the carrier's body frame.According to quantitative analysis,the heading error of AHRS caused by inter-triad misalignment consists of constant and sinusoidal components.Using the constant dot product of geomagnetic vector and gravity vector,additional with small angle approximation of three dimensional rotation matrices,the inter-triad misalignment left by ellipsoid fitting method can be compensated.With different magnetic disturbances,the residual heading error(RMSE)can be reduced over 30% on average.