FMG载荷地面试观测导行跟踪系统的设计与实现

全日面矢量磁像仪(Full-disk vector MagnetoGraph, FMG)是先进天基太阳天文台(Advanced Space-based Solar Observatory, ASO-S)卫星的3台主载荷之一,为开展FMG全系统性能测试和定标试验,已搭建用于FMG外场测试的地面试观测平台.利用该平台模拟FMG在轨跟踪状态,研制了基于全日面太阳图像的望远镜导行系统.该系统通过大面阵CCD (Charge Coupled Device)采集太阳像、多重逻辑条件判定、微调恒动跟踪速度校正偏移等策略,实现了RMS (Root Mean Square)优于1′′/30 min的跟踪精度.通过分析FMG方案阶段试观测的太阳纵向磁图,开启导行30 min后磁图特征点在赤经方向的偏移比恒动条件下减少17.5′′,提升了磁图空间分辨率.测试过程中该系统达到设计指标且工作稳定,为FMG地面试观测提供了良好的技术支撑.

Design and Implementation of Guiding and Tracking System for Ground-based Experimental Observation of FMG Payload

The Full-disk vector MagnetoGraph (FMG) is one of the three main payloads of the Advanced Space-based Solar Observatory (ASO-S). In order to conduct the overall system performance testing and the calibration experiment of FMG, a ground-based experimental observation platform of FMG payload was established. We use this platform to mimic the tracking states on orbit of the FMG working platform, and we developed a tracking system based on the full-disk solar image processing. The system realizes tracking accuracy better than 1$''$/30min RMS (Root Mean Square) by using a large-area array CCD (Charge Coupled Device) to collect solar images, to judge multiple logic conditions, to fine-tune the perpetual motion speed, and to complete the offset correction and other strategies. By comparing and analyzing the solar longitudinal magnetograms during the experimental observation of the planning phase, the deviation of the feature point in the right ascension direction is 17.5$''$, less than that under perpetual motion condition, which improves the spatial resolution of the magnetic field images. The system achieved the design target and worked stably during the experimental observation, which provides a robust technical support for FMG test observations.