基于绝对磁场测量的磁通门磁强计在轨标定方法

A Method of in-orbit Calibration of Fluxgate Magnetometer Based on the Measurement of Absolute Scalar Magnetometer

卫星在轨进行磁场测绘及监测时,需要高精度的磁场值,但由于磁通门磁强计三轴非正交性以及零点漂移所引起的误差大大降低了磁强计的测量精度,因而有必要对此进行校正.本文利用绝对标量磁强计,采用一种改进的最小二乘标定算法,通过不断迭代实现对磁通门三轴正交性和零点漂移的修正.结果表明,在考虑了磁强计本身噪声水平的实际情况下,磁通门磁强计的误差可由100 nT左右修正到0.2 nT以内.该算法为卫星在轨高精度磁场测量提供了一种可行的方法.

High precision measurement of the magnetic field is required for in-orbit magnetic field monitoring and mapping. Due to the restrictions of processing technology and installation, the three axes of fiuxgate magnetometer cannot be strictly orthogonal and the offsets in three directions are unknown in actual measurement. To solve this problem, it is necessary to determine the alignment and offset of the fiuxgate magnetometer in-orbit instead of on the ground. According to the method of calibrating with scalar magnetometer, a method for calibrating the alignment, sensitivity, and offset by an improved least square calibration algorithm is proposed. Results show that considering the noise of detector itself, the error of fluxgate magnetometer can be reduced from about 100 nT to less than 0.2 nT. This calibration algorithm offers a feasible way of in-orbit high-precision measurements.