Liu En-chao, Li Xin, Wei Wei, Zhai Wen-chao, Zhang Yan-na, Zheng Xiao-bing
Guang Pu Xue Yu Guang Pu Fen Xi. 2016 Dec;36(12):4076-81.
With the demand of calibration technology of high frequency and high precision in terms of the optical remote sensing satellite of China, and the deficiency of the artificial work, the automatic system of hyper-spectral ratio radiometer was developed by investigation the calibration situation of domestic and abroad satellite, then the automatic calibration of satellite sensor was carried out. According to the parameters demand of field calibration and the goal of automation, the ratio radiometer was designed to measure global spectral irradiance by integrating sphere, and the diffuse spectral irradiance was measure by the shelter, so the diffuse-global ratio was calculated by these data. Simultaneity the ground radiation was measured with radiometer optical-lens and the automatic observation of atmospheric and surface radiation characteristics was achieved, In addition, the data pre-processing of real-time and remote transmission were integrated in the system. With the field test on the Dunhuang radiometric calibration sites in 2015, the radiometer worked in an ideal way, and the atmospheric optical parameters and surface reflectance data were acquired, which support the calibration of satellite sensor. The comparison with the traditional measurement was carried, the relative deviation of the surface reflectance is less than 5%, and the absolute deviation of the atmospheric parameters is less than 5% and the diffuse ratio is less than 0.015%. According to the measured data and based on irradiance-based method, the field calibration applied to the band 15 of Aqua MODIS, the relative deviation of band 14 is less than 1% while the band 57.24%, so the requirement of the automatic calibration of the satellite sensor was satisfied preliminarily.
针对我国光学遥感卫星高频高精度定标技术需求以及人工工作的不足，通过调研国内外卫星定标情况，研制了超光谱辐射计自动定标系统，进而开展卫星传感器的自动定标工作。根据野外定标参数需求和自动化目标，设计辐射计利用积分球测量全球光谱辐照度，利用遮光罩测量漫射光谱辐照度，进而计算漫射-全球比。同时利用辐射计光学镜头测量地面辐射，实现大气和地表辐射特性的自动观测，此外系统还集成了实时数据预处理和远程传输功能。通过2015年在敦煌辐射定标场的野外试验，辐射计工作状态理想，获取了大气光学参数和地表反射率数据，为卫星传感器定标提供了支撑。与传统测量进行了对比，地表反射率相对偏差小于5%，大气参数绝对偏差小于5%，漫射比小于0.015%。根据测量数据，基于辐照度法对Aqua MODIS的15波段进行野外定标，14波段相对偏差小于1%，5波段为7.24%，初步满足了卫星传感器自动定标的要求。
