为了满足星上载荷高频次的在轨定标需求,常使用场地自动化定标技术将多光谱反射率反演为高光谱反射率,所以提升光谱的反演精度对提高自动化定标精度尤为重要。使用布设在敦煌辐射校正场的通道式自动化观测仪器计算从2018年9月至2019年9月的反射率;根据测量过程中太阳天顶角的不同将数据分为6组,并使用双向反射分布函数模型对不同太阳天顶角下的光谱形状进行一致性分析。实验结果表明,双向反射分布函数模型校正不同入射角度是有效的。

In order to meet the high-frequency on-orbit calibration requirements of the on-board load, the site automatic calibration technology is often used to invert the multi-spectral reflectance into the hyper spectral reflectance, so it is particularly important to improve the precision of automatic calibration to improve the inversion accuracy of spectrum. In this paper, we calculate the reflectance from September 2018 to September 2019 using a channel-type automated observation instrument deployed in the Dunhuang radiometric calibration site. Furthermore, we divide the data into 6 groups according to the difference in the solar zenith angles during the measurement process and employ the model of bidirectional reflectance distribution function (BRDF) for the consistency analysis of spectral shapes at different solar zenith angles. The experimental results show that the BRDF model is effective for correcting the data at different incident angles.