Development of examination and correction system for satellite-borne fluxgate magnetometer

对于星载或箭载磁通门磁力仪的地磁场测量，飞行数据的校正和地面标定是非常重要的。研制了一套由三轴亥姆霍兹线圈、控制计算机、多路电源、数据记录仪和分析程序组成的磁力仪检定系统。测试磁力计固定在亥姆霍兹线圈的中心。如果将卫星运动的规定值输入计算机，磁强计数据将显示出与卫星运动相对应的自旋频率、岁差角和周期的模拟变化。由计算机对多个电源发出指令，控制三轴线圈中交流电流的幅值、相位和频率。由于......通过试验，为磁力仪的测试提供了良好的模拟输出数据。输出数据由数据记录仪采集并传送到上位机。通过分析程序，确定了修正参数。这些参数是非矩形传感器轴之间的精确角度、传感器对磁场强度的灵敏度以及来自卫星体或仪器的磁场偏移场。该程序由最小二乘法和非直角坐标系与直角坐标系之间的坐标变换两部分组成。使用“AKEBONO”科学卫星数据估算了校正值。将三轴磁通门磁力仪传感器安装在5 m长的桅杆上，获得了32 Hz的地磁场矢量采样数据。通过使用校正系统，能够确定每个传感器的角度为89.902-89.962度，磁偏移为22-189 nT。结果表明，所研制的检测线圈装置和分析程序对星载磁强计的校正是十分有效的。

For the geomagnetic field measurement by use of rocket or satellite-borne fluxgate magnetometer, correction of flight data and calibration on the ground are very impotant. I have developed an examination and correction system for magnetometer that was composed of a tri-axial Helmholtz coil, control computer, multiple power suplies, data recorder and analysis programs. A test magnetometer is fixed in the center of the Helmholtz coil. If institution value of satellite motion are given to the computer, the magnetometer data shows simulant changes correspondence to the satellite motion which are spin frequency, precessional angle and period. The computer gives commands to multiple power supplies and AC current is controled an amplitude, phase and frequency in the tri-axial coil. As a result of. the examinaction, good simulant output data is obtained for a test magnetometer. The output data is acquired by data recorder and is transmitted to the host computer. By the analysis programs, the correction parameters are determined. The parameters are precise angles between non-rectanglar sensor axes, sensor sensitivity for magnetic intensity and magnetic offset field from satellite body or instruments. The programs are composed of the least square method and coordinate transformation between the non-rectanglar and rectanglar system. The correction was estimated by use of the "AKEBONO" scientific satellite data. The tri-axial fluxgate magnetometer sensors boarded on the 5m-extension mast and 32Hz-sampled data of geomagnetic field vector were obtained. By use of the correction system, itwas able to determine that each sensor angle were 89.902-89.962 degrees and magnetic offset were 22-189 nT. In consequence, it is confirmed that the examination coil equipment and the analysis programs are very effective for satellite-borne magnetometer correction.