顾及多积分时间特性的GF-4卫星PMS传感器交叉辐射定标

针对GF-4卫星PMS传感器具备5个积分时间的成像特性，提出一种基于辐射区域网平差的交叉辐射定标方法。首先，利用敦煌辐射校正场地区时间序列有效MODIS影像集，构建该区域高精度BRDF模型。其次，考虑BRDF和SBAF校正，从该地区Landsat-8卫星OLI影像和PMS影像中提取辐射控制点。然后，设置DN值和CV限制条件，在凝视成像状态下从不同积分时间PMS影像中提取辐射连接点。最后，利用新建定标模型计算各积分时间状态下的定标系数。验证结果表明，不同积分时间的各波段平均绝对定标精度均优于5.18%，且不同积分时间影像间各波段辐射差异最高降低36.64%。同时，探讨了辐射控制点分布、BRDF、SBAF和辐射连接点筛选条件对定标结果的影响，为进一步优化PMS传感器交叉辐射定标流程提供重要参考。

Radiometric cross-calibration of GF-4 satellite PMS sensor considering the characteristics of multiple integration times

Integrating the five integration times characteristics of GF-4 satellite PMS sensor,a radiometric cross-calibration method based on the radiometric block adjustment is proposed. Taking Dunhuang radiometric calibration sites (DRCS) in China as the radiometric transfer platform. Firstly, collecting the valid time-series MODIS images over DRCS to build the BRDF model. Secondly, considering the SBAF and BRDF, the radiometric control points (RCPs) are extracted from the image pairs of Landsat-8 OLI and PMS over DRCS. Thirdly, after setting the restrictive conditions of DN and CV, the radiometric tie points (RTPs) are extracted from PMS images in different integration times under the stare imaging condition. Finally, the radiometric cross-calibration coefficients of five integration times are solved based on the proposed method. The validation results show that the average absolute calibration relative errors of five integration times are all less than 5.18% and the relative radiometric correction errors of five integration times reduce up to 36.64%. Meanwhile, the influences of the RCPs distribution, the restrictive conditions in the process of RTPs extraction, SBAF and BRDF on the calibration results are discussed, which is beneficial to further optimize the radiometric cross-calibration program of PMS.