大气与环境光学学报, 2019, 14 (1): 18, 网络出版: 2019-04-02
GF-5卫星多角度偏振成像仪在轨偏振定标
In-Flight Polarimetric Calibration of Directional Polarization Camera on GF-5 Satellite
定标 线偏振度 太阳耀光 多角度偏振成像仪 calibration degree of linear polarization the sun glint directional polarization camera
摘要
2018年5月,我国成功发射了高分5号卫星,其上搭载了多角度偏振成像仪。卫星载荷受发射时的振动、在轨空间环境变化以及元器件电路 系统老化等因素的影响,各种辐射特性发生变化,从而导致整个载荷辐射性能与在轨前的实验室定标结果之间存在一定偏差。 基于海洋耀光对高分5号卫星多角度偏振成像仪的偏振测量定标的方法,并利用在轨测试期间数据,对载荷进行了初步的偏振辐射 定标测试。测试结果表明, 3个偏振波段(490, 670, 865 nm)线偏振度测量值与理论值有很好的一致性,平均偏差分别约为-0.03、 -0.04、-0.01,载荷发射前后偏振测量状态未发生明显改变。基于自然目标的在轨替代定标方法,还可用于多角度偏振成像仪 偏振辐射性能随时间变化情况的长期监测。
Abstract
The Chinese GF-5 satellite was launched successfully in May 2018, which was equipped with a directional polarization camera (DPC). The DPC sensor’s radiometric characterization may be affected by many factors, such as the vibration during launch, the outgassing when instrument leaves atmosphere, the ageing of the optics and circuit system, resulting in a certain deviation between the in-flight performance and the preflight radiometric calibration. Based on the in-flight calibration method for polarization measurements of DPC, using the sunlight reflected within the sun’s glitter over ocean, the DPC measurements were adopted during its commissioning phase. The preliminary result shows that the measured degree of linear polarization values are consistent with the theoretically values, with small average deviations of -0.03, -0.04, -0.01 for 490, 670, 865 nm bands, respectively. It indicates that the DPC’s polarimetric characterization have not been changed significantly after launch. This method is based on natural target, and it can be used to monitor the temporal polarimetric sensitivity of DPC.
李照洲, 伽丽丽, 谢一凇, 朱思峰, 李正强, 潘志强. GF-5卫星多角度偏振成像仪在轨偏振定标[J]. 大气与环境光学学报, 2019, 14(1): 18. LI Zhaozhou, QIE Lili, XIE Yisong, ZHU Sifeng, LI Zhengqiang, PAN Zhiqiang. In-Flight Polarimetric Calibration of Directional Polarization Camera on GF-5 Satellite[J]. Journal of Atmospheric and Environmental Optics, 2019, 14(1): 18.