本文将介绍电磁监测试验卫星（张衡一号）磁场探测载荷高精度磁强计的设计、研制和标定的情况。根据卫星平台观测磁场的特点，以及电磁监测试验卫星对矢量磁场准确度的需求，设计了矢量结合标量的磁场探测方案。高精度磁强计包含2个磁通门探头及1个绝对磁场校准装置探头，安装在卫星舱外伸杆的顶部。通过对高精度磁强计飞行件进行了线性度试验、温度试验、磁轴与结构坐标系转换标定试验、传感器互扰试验和CDSM转向差试验的测试，对磁场探测方案和高精度磁强计的性能进行了验证，并为地面数据处理提供了依据。按照所设计的磁场探测方案，高精度磁强计完成了全部的载荷研制、理论算法研究、标定试验等地面工作，载荷性能指标和地面数据能够满足电磁监测试验卫星的磁场探测任务要求。

The internal structure of the Earth and its geomagnetic distribution and spatial environment can be studied by exploring the near-Earth magnetic field. The China Seismo-Electromagnetic Satellite (CSES) is the first satellite of this kind in a near-Earth orbit. Its scientific goals include the real-time monitoring of electromagnetic changes by studying the Earth system, especially the ionosphere and the mutual actions of other spheres. Obtaining information on ionospheric response before and after an earthquake is the main goal. The magnetic field is one of the most important physical parameters for monitoring the ionosphere. A High-Precision Magnetometer (HPM) is responsible for the accurate measurement of magnetic field vector components from DC to 15 Hz.
The magnetic environment of the spacecraft and the vector value accuracy requirement for magnetic field detection are considered. The HPM consists of two fluxgate sensors and a CDSM scalar sensor. The fluxgate sensors provide the vector components of the magnetic field but with limited accuracy and long-term stability. The CDSM sensor measures the scalar of the magnetic field with high accuracy and stability and is therefore used to calibrate the vector data. Satellite remanence magnetic interferences can be reduced with the help of two fluxgate sensors.
Several ground data processing methods used to obtain the actual accuracy vector magnetic field data were considered, including the physical calibration of the single sensor, the absolute vector correction algorithm, the remanence magnetic interference elimination, and the coordination conversion method. Several ground calibration tests were conducted to obtain the actual performances.
This article also introduces the development of sensors and electronics, as well as provides the data processing procedure and method, and the calibration results.
Several algorithms were developed and presented in this article according to the requirement of the ground data processing method. Several key calibration tests were conducted to obtain the linearity, the thermal drift results, the coordination relations between the FGM magnetic axis and the sensor structure, the disturbances of sensors, and the heading error of the CDSM sensor. The results are shown in the table below. Calibration results show that the performances of the HPM satisfy the specifications.
HPM development provides a magnetic field exploration method for a near-earth orbit satellite. The schedule indicates that HPM has completed all development and calibration works before the satellite launch. All the performances and data processing procedures satisfy the requirements defined for the CSES mission.