一种消除双探头磁通门磁强计在磁场测量中邻频干扰的方法

A Method of Eliminating Adjacent Frequency Interference in Magnetic Field Measurement of Double Probe Fluxgate Magnetometer

风云四号卫星A星搭载高精度磁通门磁强计,是国内首次对地球同步轨道开展高精度磁场探测。仪器采用双探头梯度法测量消除卫星本体的剩磁,实现高精度、高可靠性,双探头共用电子学箱减轻了仪器重量。但由于双探头磁强计各自采用独立同频频率源,带来了双探头同时工作时的邻频干扰问题。该文分析了邻频干扰产生的原因,比对了几种削弱电磁波空间辐射影响的方法及可行性,最终采用扩大频率源的频差,在信号处理中增加二级有源低通滤波的处理方法。实验结果表明,该方法能够将邻频干扰噪声幅度衰减2个数量级以上,满足任务需求,从根本上解决磁通门磁强计双探头梯度法测量方案中的邻频干扰问题。

FY-4(A)satellite is equipped with high-precision fluxgate magnetometer,which is the first time in China to carry out high-precision magnetic field detection in GEO orbit.The dual probe gradient method is used to measure the residual magnetism of the satellite body to achieve high precision and reliability.The electronic box shared by the two probes reduces the weight of the instrument.However,because the dual probe magnetometer adopt independent frequency source with the same frequency,it brings the problem of adjacent frequency interference when the two probes work at the same time.This paper analyzes the cause of adjacent frequency interference and compares several methods to weaken the influence of electromagnetic wave space radiation.Finally,the processing methods of enlarging the frequency difference of frequency source and adding two-stage active low-pass filter at the output of preamplifier are used.The experimental results show that the methods can attenuate the adjacent frequency interference amplitude by more than 2 orders of magnitude,which can meet the task requirements,and fundamentally solve the adjacent frequency interference problem in the measurement scheme of fluxgate magnetometer with double probe gradient method.