卫星光学仪器辐射交互定标方法的应用和发展

Development and applications of intercalibration for satellite optical instruments

卫星遥感器的在轨交互定标是保证仪器数据记录的可靠性、连续性和一致性的核心方案,配合高精度的在轨参考基准仪器可使定标精度达到2%左右。本文介绍了交互定标技术的相关概念和意义,强调该技术是修正仪器间辐射定标相对偏差的重要手段。指出了交互定标的前提条件及现存难点。总结了交互定标实现流程,包括数据收集、匹配、筛选、处理,基准确定,精度分析等,分析了影响交互定标精度的各种因素。叙述了当前卫星光学遥感器交互定标的各类方法及其使用条件,总结了不同应用条件下所适用的各交互定标方法的定标精度。最后结合当前交互定标的国际合作活动,分析展望了未来光学遥感器在轨可溯源SI定标方法的前景趋势和难点问题。

The on-orbit intercalibration between satellite instruments is the central method to ensure the reliability,consistency and the continuity of observation data. The calibration uncertainty of 2 % has been achieved combined with high-accuracy reference on-orbit instruments. This paper introduces the concepts and significance of the intercalibration and emphasizes which is a main way to correct the relative deviation of radiation calibration between instruments. It gives the basis conditions to com- plete the intercalibration and discusses the existing difficulties. Then, the realized process of the in- tercalibration is summed up such as the data collocating, filtering, correcting, reference changing and accuracy analyzing, and the effect factors on the calibration accuracy are analyzed. Moreover, it describes the current intercalibration methods for satellite optical remote sensing and needed conditions and summarizes the uncertainty of different intercalibration methods under different conditions for post-launch radiometric calibration of satellite remote sensors. In the end, this paper introduces a few international organizations and some ongoing joint campaigns with focusing on instrument calibration and validation, which shows the recent advance of research on the SI intercalibration in orbit.