基于太阳漫射板的星上定标方法研究

基于太阳漫射板的星上定标方法是一种具有高精度、高频次、高效率等优点的独立定标方法，是目前提高我国遥感定标精度的重要手段之一。文章阐述了基于太阳漫射板的星上定标原理、方法及实现过程，建立了空间辐射标准，同时给出了星上反射率定标物理模型。分析定标物理模型发现，影响星上定标不确定度最主要的因素是太阳漫射板BRDF实时量值的确定。为此，首先介绍了星上定标时机的选择，根据所确定定标时机的太阳照明角度对太阳漫射板在实验室相应入射角度下的BRDF进行了测量。通过对太阳漫射板从制作完成到星上使用寿命终结整个过程中各阶段的BRDF量值的监测及修正，确保太阳漫射板定标时刻可为遥感器提供精确已知的辐射输入，实现遥感器全寿命期的高精度星上定标。最后，结合国内对定标模型中相关参数项测量的不确定度水平，按照测量不确定度B类评定的方法对基于太阳漫射板星上定标不确定度进行了预估，可实现星上反射率定标不确定度优于2.03%，绝对辐射定标方法不确定度优于2.04%。

The Research of On-Orbit Calibration Method Based on Solar Diffuser

As one of the most important ways of improving the calibration accuracy at present,the calibration method based on a solar diffuser(SD) is an independent calibration way with advantages of high accuracy,high frequency and high efficiency .The principles,methods and implementation process of on-orbit calibration based on the SD is described in this thesis .The radiance reference for calibration in space is found and the physical model of the on-orbit reflectance calibration is provided .The main factor which affects the calibration uncertainty is the determination of the SD bidirectional reflectance distribution function (BRDF) value by analyzing the physical models of on-orbit calibration .Thus,the timing selection of the on-orbit calibration is introduced and the BRDF in the range of angles variety within the calibration timing is tested in the lab .During the on-orbit calibration time,the high accuracy on-orbit calibration in the remote sensors' whole life is achieved by the accurate radiance input which is ensured by monitoring and correcting the SD BRDF value from its fabrication to its life end .Finally,the on-orbit calibration uncertainty is estimated based on the measurement levels of the parameters in the physical model .And the uncertainties of on-orbit reflectance calibration and method of radiance calibration are better than 2.03％ and 2.04％ by type B standard uncertainty evaluation method .