“巴遥一号”卫星双相机在轨绝对辐射定标及精度分析

On-orbit Absolute Radiometric Calibration and Accuracy Analysis for Dual Camera of PRSS-1 Satellite

“巴遥一号”卫星作为中国整星出口巴基斯坦的第一颗光学遥感卫星,搭载了两台全色/多光谱高分辨率相机,每台相机全色波段的像元分辨率为1m,多光谱波段(蓝、绿、红及近红外)的像元分辨率为3m。为满足“巴遥一号”卫星双相机绝对辐射定标精度7%(2σ)的指标要求,文章采用基于灰阶靶标的绝对辐射定标方法,在敦煌定标场开展了为期56天的试验,得到了双相机的绝对辐射定标参数,然后进行定标不确定性评估并与基于大面积均匀场反射率法的MODIS结果、基于太阳-漫射板的MODIS星上定标结果进行交叉定标验证。结果表明,文中方法获取的“巴遥一号”卫星双相机定标绝对辐射精度为5.2%(2σ),满足其绝对辐射定标指标要求和定量化应用要求。

PRSS-1 satellite is the first optical remote sensing satellite exported to Pakistan by China.It is equipped with two PMS cameras.Every camera provides 1m pixel resolution in the PAN band and 3m pixel resolution in the four MSS bands(blue,green,red and near infrared).In order to meet the requirements of 7%(2σ)absolute calibration accuracy of the PRSS-1 satellite dual camera,the author conducted a 56-days test in the Dunhuang field using the absolute radiometric calibration method based on gray target,obtained the absolute radiometric calibration parameters of the dual camera.Finally,the calibration uncertainty assessment was carried out,and cross-calibration verification was performed based on the MODIS results of the large-area uniform field reflectivity method and the on-board calibration MODIS results based on the solar-diffuse plate.The absolute radiometric calibration accuracy of the PRSS-1 satellite dual camera obtained by this method is 5.2%(2σ),which satisfies the absolute radiometric calibration index and quantitative application requirements.