资源三号卫星靶标法绝对辐射定标与验证分析

Absolute radiometric calibration and validation analysis of ZY-3 using artificial targets

为获取资源三号卫星高精度绝对辐射定标系数,文章采用一种基于光谱特性均一的多级灰阶靶标在轨定标方法,实现了ZY-3卫星的在轨辐射定标。首先设计靶标法辐射定标技术流程,分析了灰阶靶标实测反射光谱的波动误差,并基于同步试验获得了ZY-3卫星定标系数,最后利用实验室定标系数和场地实测数据对新的定标结果进行了真实性检验。结果表明:基于多级灰阶靶标的定标方法不确定度小于4.71%,获取的定标系数精度可靠;ZY-3卫星自发射以来载荷辐射性能稳定性较好,与发射前定标系数相比,除多光谱相机蓝、绿波段变化了11.76%和5.07%以外,其余载荷波段变化小于1%。

To achieve accurate absolute radiometric calibration coefficients of ZY - 3 satellite, this paper takes ad- vantages of gray - scale artificial targets with the homogeneous spectral property for wider dynamic absolute radio- metric calibration for ZY - 3 satellite. Firstly, the method flow of calibration based on gray - scale targets was de- signed and the uncertainty in measurement of targets reflectance was analyzed. Secondly, the calibration coeffi- cients of ZY - 3 were achieved by using test - site measurement date during the satellite passing through. By using laboratory calibration results and measurement data to validate the calibration results of ZY - 3 base on artificial targets method, it show that the uncertainty of in - flight calibration method base on gray - scale artificial targets was less than 4.71% ; since launched, the radiometric property stabilization of ZY -3 satellite sensors was very well, the relative changing of most sensors were around 1% besides blue band （11.76%） and green band （5.07%）.