一种利用恒星进行遥感卫星辐射定标的方法
Received:November 15, 2016  Revised:March 06, 2017  点此下载全文
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XU Chun Shanghai Institute of Technical Physics, Chinese Academy of Sciences chun.xuu@qq.com 
基金项目:红外物理国家重点实验室开放课题
中文摘要:恒星巡天测量与模型分析显示大量恒星在0.3-35μm波段内的绝对辐射精度达到3%,在可见光波段接近1%。恒星与恒星之间的相对辐射定标精度优于0.2%。部分恒星具有极好的辐射稳定性,可以作为长期稳定的辐射基准。但是恒星有效亮度通常比地面目标低几个量级,并且一般不会直接出现在遥感相机视场,不利于用作定标源。这里讨论的利用恒星进行辐射定标的方法是通过在遥感卫星上安装一个与遥感相机波段接近的微型定标相机,它的指向可以通过转动机构在恒星与地表之间转换,在观测恒星时通过延长积分时间来获取高信噪比信号,在观测地面目标时可以和遥感相机同时同视场观测有利于交叉定标。这个方法可以将恒星的辐射标准直接传递到观测目标。目前分析显示最佳定标精度可以达到2%以内。
中文关键词:辐射定标  恒星;遥感卫星
 
A flux calibration method for remote sensing satellites using star flux
Abstract:Star surveys and model analyses show that many stars have absolute stable fluxes as good as 3% in the 0.3-35μm wavebands, and about 1% in the visible bands. The relative flux calibrations between stars are better than 0.2%. Some stars have extremely stable fluxes and can be used as long term flux calibrations. Stars’ effective brightness is however order of magnitude’s lower than most ground objects and they don’t usually appear in remote sensing cameras. This makes the stars inappropriate for being calibration sources. The calibration method using stars discussed here is through a mini-camera attached to remote sensing satellite. The mini-camera can observe the star fields and the grounds alternatively and it works at similar wavebands as the remote sensing cameras. High signal-to-noise is possible through long-time exposure when the mini-camera observes the stars. Precise simultaneous cross-calibration is obtainable when the mini-camera and remote sensing cameras look at the same ground objects. The standard calibrations from the stars are then transferred to the remote sensing cameras through this procedure. The analysis shows that a 2% accurate calibration is possible.
keywords:flux calibration  stellar  remote sensing satellite
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Copyright:《Journal of Infrared And Millimeter Waves》