地磁测量卫星的矢量磁场在轨标定算法仿真

Simulation of Vector Magnetic Field In-orbit Calibration Algorithm for Geomagnetic Survey Satellite

以SWARM为代表的高精度地磁测量卫星对地球磁场探测精度经过标定之后优于0.5 nT,对于开展地磁科学研究具有重要意义。地磁测量卫星通过安装在伸展杆上的矢量磁通门磁强计、标量磁强计和高精度星敏感器,获取测量方向的惯性空间姿态的地磁信息,其中高精度标量磁强计主要用于对磁通门矢量磁强计进行标定。针对地磁测量卫星,研究了矢量磁强计在轨测量误差的校正方法。考虑到矢量磁强计非正交角、标度因子以及偏差的影响,建立磁场矢量线性输出模型;结合标量磁强计的测量值分别设计基于小量近似的线性校正算法和基于参数辨识更新的非线性校正算法;校验两种算法的标定精度,并通过Tukey权重函数改善算法的鲁棒性。仿真结果表明,两种算法校正结果相似,磁场三轴误差可校正至0.5 nT以内,在标量磁强计存在异常值时仍具有较好的校正效果。

The precision of geomagnetic survey satellites represented by SWARM is better than 0.5 nT for detection of the Earth’s magnetic field after calibration.The satellites obtain the geomagnetic information of inertial space attitude in measurement direction through the vector fluxgate magnetometer,scalar magnetometer and high-precision star tracker installed on the extension boom.The high-precision scalar magnetometer is mainly used to calibrate the fluxgate vector magnetometer.Calibration methods of in-orbit measurement error of vector magnetometer are proposed for geomagnetic survey satellite.Considering the non-orthogonal angles,scale factors and deviations of vector magnetometer,the linear output model of magnetic field vector is established.The linear correction algorithm based on small approximation and nonlinear correction algorithm based on parameters identification update are designed respectively combined with the measurement values of scalar magnetometer.The calibration accuracy of algorithms is verified,and the robustness of the algorithms is improved by Tukey weight function.Simulation results show that the correction results are similar,the triaxial errors of magnetic field can be corrected to less than 0.5 nT,and the algorithms still have a good correction effect when there is an outlier in scalar measurements.