大视场偏振多光谱相机比传统的光谱相机多探测角度和偏振两个维度的信息, 尤其在气溶胶遥感监测领域, 具有很大优势, 所以在2020年前后全球将大量发射搭载该类载荷的卫星。 作为定量化程度很高的光学载荷, 在轨定标一直受到很大的重视。 因受限于缺乏星上定标设备和低空间分辨率特点, 使用自然景物作为替代参考光源进行在轨辐射定标。 多角度偏振相机内部的辐射传递过程复杂, 需要进行辐射定标的相机参数有多个。 辐射定标系数包括辐射强度和偏振两种类型多个参数, 使用的自然景物类型多, 导致多种定标方法组合、 并行发展。 2018年新发射的高分五号卫星是我国第一颗, 也是同期国际上唯一搭载偏振运行载荷的卫星, 在其后国际上也会有多颗卫星搭载同类型传感器上天, 有必要梳理替代定标的研究进展情况。 文章系统介绍了大视场偏振多光谱相机的一般光学结构及其光谱设置等重要技术参数, 梳理了相机的辐射传递模型。 划分了绝对辐射强度、 相对辐射强度和偏振参数三类来描述不同定标系数的在轨定标方法和原理。 针对特定的待定标系数, 介绍了在轨替代定标所需选用的自然景物目标和定标的流程方法。 形成了大视场偏振多光谱相机在轨辐射定标的方法系统。 并汇总了定标结果检验的一般方法。 新的大视场偏振多光谱相机的在轨辐射定标, 将继承原有研究基础, 使用特殊自然景物开展定标。 在后续的同类遥感相机在轨定标工作中, 也可以充分借助同一个卫星平台上的其他载荷及其星上定标器、 借助地面人工光源等方法开展新形式的在轨辐射定标。 我国、 欧洲以及美国等规划了新型偏振相机航天发射计划, 面向未来几年的我国和欧美诸多同类相机, 结合作者研究基础, 对未来在轨定标方法进行了初步设计和展望。 偏振类型的多光谱相机主要服务于大气颗粒物遥感监测, 对我国当前关注的大气环境问题非常重要。 卫星发射后持续的在轨辐射定标是保障卫星遥感产品反演精度的必要条件。 系统的在轨定标研究梳理和在轨定标未来方法的初步设计将为后续卫星遥感应用系统提供方法和模型参考。

The large view, polarized and multispectral camera detects the angular and polarized two more dimensional information than a traditional optical multi-spectral camera, and has great advances especially in aerosol remote sensing. So, near the year of 2020, a number of satellites loading multi-angle and polarized camera would be launched in different countries. As a high quantitative sensor, its in-flight calibration has always been attractive. Due to the lack of onboard calibration instrument and the low spatial resolution, the natural scenery targets are selected to be vicarious optic references for the calibration. Multi-angel polarized camera has several parameters to be calibrated. The radiometric calibration of polarized camera includes intensity and polarization parameters. Different calibration parameters are calibrated using many natural targets by many methods which are developed in parallel. The Gaofen-5 launched in 2018 is the first satellite loading polarized sensor of China, also the only operational satellite in the world this time. In view of many new polarized camera aerospace plans in European and American countries and China, the vicarious calibration for polarized camera is necessary to overview. In this paper, the optical structure and the spectral settings of the large view, polarized and multispectral camera are presented. The optical transfer model of camera is introduced. The in-flight calibration theory and method of each camera parameter is classified into three categories including absolute radiometric intensity, relative radiometric intensity and polarization. For a specified calibration coefficient, the natural target and calibration flow are introduced for the in-flight calibration. The method system is formed for the in-flight radiometric calibration of the large view, polarized and multispectral camera. Also, the general validation methods of calibration are concluded. The in-flight calibration of the new large view, polarized and multispectral camera will inherit the original research and use special natural scenery to carry out calibration. In the same kind of future remote sensing camera, new style in-flight radiometric calibration will be based on the instruments and its calibrator onboard the same satellite platform, ground-based artificial optical source and others. China, Europe and America have planned some future polarized camera, jointly considering the research basis of authors, preliminary design and prospects for the future on-orbit calibration method are given. A polarized multispectral camera mainly serves the remote sensing monitoring of atmospheric particulate matter, which is very important for the atmospheric environment problems currently concerned in China. A continuous in-flight calibration can ensure the accuracy of satellite remote sensing retrieved products. This overview of in-flight calibration research and the preliminary design for the future calibration method will provide method and model references for the remote sensing application system of the planned satellite.