基于RadCalNet包头场的高分七号卫星在轨绝对辐射定标及精度验证  

On-orbit radiometric calibration and Validation of GF-7 satellitebased on RadCalNet Baotou site

作　　者：唐洪钊 唐新明 谢俊峰 陈伟[2] 钱永刚 TANG Hongzhao;TANG Xinming;XIE Junfeng;CHEN Wei;Qian Yonggang(Land Satellite Remote Sensing Application Center,Ministry of Natural Resources,Beijing 100048,China;China University of Mining and Technology(Beijing),Beijing 100083,China;Aerospace Information Research Institute,Chinese Academy of Sciences,Beijing 100094,China)

机构地区：[1]自然资源部国土卫星遥感应用中心,北京100048 [2]中国矿业大学(北京),北京100083 [3]中国科学院空天信息创新研究院,北京100094

出　　处：《遥感学报》2023年第5期1194-1204,共11页NATIONAL REMOTE SENSING BULLETIN

基　　金：国家重点研发计划(编号:2018YFB0504800,2018YFB0504801)~。

摘　　要：针对2019年11月发射的首颗民用亚米级高分辨率立体测绘卫星高分七号的影像数据特点,2020年9月在内蒙古包头高分辨率遥感综合定标场开展了卫星在轨辐射定标试验。利用包头场固定辐射灰阶靶标和AERONET AOE-Baotou站点同步观测反演的大气气溶胶物理及光学特性参数,基于反射率基法对高分七号卫星传感器进行了在轨场地绝对辐射定标,获取了卫星在轨辐射定标系数,实现了传感器全动态范围内的高精度辐射定标。同时基于包头场均匀沙地的自动观测数据对辐射定标系数进行了精度验证。试验结果显示,高分七号卫星自发射以来立体测绘相机的辐射性能稳定,相机各波段影像DN值与表观辐射亮度的线性相关系数优于99%。通过误差分析可知,高分七号卫星包头场辐射定标的不确定度优于5%,获取的定标系数精确可靠,获取的辐射定标系数可用于地物参数的反演,对实现我国国产立体测绘卫星数据定量化应用、提高定量遥感科研水平都具有重要意义。The aim of this study is to obtain a reliable,high-precision radiometric calibration coefficient for the GF-7 satellite sensor.In this study,we describe the methods and results of a reflectance-based vicarious calibration campaign that was conducted in September 2020 at RadCalNet Baotou Site located in Inner Mongolia,China.A series of gray-scale permanent artificial targets and infrastructure have been built in the Baotou site to provide effective support for the GF-7 satellite sensor’s on-orbit calibration.The reflectance-based vicarious calibration approach relies on the synchronous measurement of surface spectral reflectance and atmospheric parameters.In this campaign,synchronous measurements of surface and atmospheric conditions(including aerosol optical depth,amount of water vapor,and aerosol inversion products)at the Baotou site at the time of the GF-7 satellite’s overhead pass are obtained with an SVC HR-1024i spectroradiometer and a Cimel CE318 sun photometer.The bidirectional reflectance distribution function(BRDF)of the surface is measured with a multi-angle instrument with an SVC spectroradiometer.The synchronous measurement of surface spectral reflectance is modified by the surface BRDF model,and the atmospheric parameters are coupled with the exoatmospheric solar irradiance spectrum.The relative spectral response of the sensor is adopted as an input for a radiative transfer model to compute the at-sensor spectral radiance.The relationship between the at-sensor radiance and the digital number(DN)recorded in the GF-7 satellite image is identified.Results show a good linear relationship between DN and the apparent radiances of each band.The uncertainty of the GF-7 sensor radiometric calibration in the RadCalNet Baotou site is 4.33%,which is less than 5%.A detailed discussion of the validation analysis of the GF-7 radiometric calibration coefficient is performed using the products from the automated RadCalNet Baotou Sand site.This study can provide a site reference for the radiometric validation of C

关 键 词：遥感 辐射定标 表观辐亮度 反射率基法 包头场 高分七号卫星 

分 类 号：P2[天文地球—测绘科学与技术]