详细分析微小型无人机导航用三轴磁强计的误差来源,建立三轴磁强计的等效误差模型,提出基于两步估计算法和圆约束非对准误差估计算法的三轴磁强计现场误差校正方法。在充分考虑地磁场偏转和倾斜特性的基础上,提出适合微小型无人机应用的现场数据采样策略,能够在较少的旋转操作下获得较好的采样数据。仿真表明:在所有磁场误差都存在的情况下,使用三轴磁强计现场误差校正方法对三轴磁强计输出进行校正后推算所得的航向角误差小于1.2°,仅相当于使用工程上常用的极大极小值法校正后所得的航向角误差的8%,校正精度提升92%。基于三轴磁强计实测数据的分析也验证了三轴磁强计现场误差校正方法的有效性和实用性。

The error sources of a three-axis magnetometer are systematically analyzed, and a uniform error model specially for calibration is established. An in-suit three-axis magnetometer calibration method for micro and mini unmanned aerial vehicle (UAV)based on the two-step estimation algorithm and circle restricted misalignment calibration algorithm is proposed. Taking into full consideration the inclination and declination of the earth’s magnetic vector, the proposed in-suit data sampling strategy can obtain excellent sphere coverage by using the fewest rotations. The simulation results indicate that in spite of all error sources existing, including strong hard iron and soft iron disturbances, the standard deviation of the magnetic heading error obtained by the calibrated magnetic data using the in-suit three-axis magnetometer calibration method is less than 1.2°, which is a mere 8% of the result obtained by using the usual industrial maximum and minimum calibration method. The precision is improved by 92%. The calibration result based on the real measurement data from a three-axis magnetometer also validates the effectiveness of the in-suit three-axis magnetometer calibration method.