地表反射率外场无人值守测量方法  

Method for unattended measurement of surface reflectance in field sites

作　　者：夏志伟[1] 王硕 衣小龙 王玉鹏[1] 方伟[1] XIA Zhiwei;WANG Shuo;YI Xiaolong;WANG Yupeng;FANG Wei(Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,China)

机构地区：[1]中国科学院长春光学精密机械与物理研究所,吉林长春

出　　处：《光学精密工程》2023年第16期2319-2332,共14页Optics and Precision Engineering

基　　金：国家自然科学基金资助项目(No.42001316)。

摘　　要：在轨运行载荷的性能不可避免地出现衰减,场地定标是一些卫星载荷在轨辐射定标主要手段之一,其精度主要取决于地表反射率的准确程度。本文介绍了地表反射率自动观测系统原理和系统组成,并在敦煌辐射校正场实现无人执守自动化、无间断的地表光谱反射率测量,采用标准白板法和辐照度法两种方法同步观测,对两种方法获取的地表反射率数据分别进行了短期和长期稳定性的对比分析,地表反射率可直接溯源至标准白板反射率,减少了定标传递环节。结果表明:标准白板法测量地表反射率短期均值偏差为0.130%,长期测量350~600 nm波段均值偏差为4.996%,600~2500 nm波段均值偏差为2.104%。标准白板法测量地表反射率合理可行,测量曲线连续、平滑、抖动少,可通过定期清洁标准白板提高测量准确性。辐照度法短期测量与标准白板法具有相近的性能,350~1900 nm波段均值偏差为0.236%,1900~2500 nm波段均值偏差为0.443%。长期测量地表反射率整体漂移小,平均漂移为0.735%,但存在反射率曲线局部噪声大的缺点。可将两种方法相结合,获得更为准确的地表反射率数据。The performance of on-orbit payloads is inevitably degraded.Field calibration is a primary method of on-orbit radiometric calibration for some satellite payloads,and its accuracy mainly depends on how accurate the surface reflectance is.This study introduces the working principle and system composi⁃tion of the Automatic Observation System of Surface Reflectance,and unattended,automated,and contin⁃uous spectral surface reflectance measurements were conducted at the Dunhuang Radiation Calibration Field.The short-and long-term stabilities of the surface reflectance data acquired simultaneously were compared and analyzed using the standard whiteboard and irradiance methods,respectively.The surface reflectance is directly traceable to the reflectance of the standard whiteboard,and the data processing meth⁃od reduces the calibration transfer link.The results are as follows.The mean deviation of short-term mea⁃surement of the surface reflectance by the standard whiteboard method is 0.130%.For the long-term mea⁃surement,the mean deviation of the 350-600 nm band is 4.996%,and the mean deviation of the 600-2500 nm band is 2.104%.The standard whiteboard method is reasonable and feasible for measuring the surface reflectance,and the figure of reflectance is continuous and smooth,and it has less fluctuation.The accuracy of reflectance can be improved by regularly cleaning the standard whiteboard.The short-term measurement of the irradiance method is similar to that of the standard whiteboard method;the mean devi⁃ation of the 350-1900 nm band is 0.236%,and the mean deviation of the 1900-2500 nm band is 0.443%.For the long-term measurement,the overall drift of the reflectance is small,with an average drift of 0.735%.However,there is a disadvantage of large local noise in the reflectance curve.The two methods can be combined to obtain accurate surface reflectance data.

关 键 词：标准白板法 辐照度法 地表反射率 自动观测系统 场地定标 

分 类 号：TP23[自动化与计算机技术—检测技术与自动化装置] P422.15[自动化与计算机技术—控制科学与工程]