高分三号SAR影像广域范围联合几何检校技术

A joint geometric calibration technique for GF-3 SAR image in wide area

在获取广域范围雷达遥感正射影像图时,需要对区域内每景SAR影像进行几何参数修正,提高SAR影像的定位精度。但在广域范围进行控制点的选取和影像的逐一修正,其工作量巨大,严重影响了SAR影像分析应用的效率。对此,本文提出了一种广域范围联合几何检校方法。该方法在R-D模型的基础上,首先利用少许SAR影像计算其独立的系统级检校参数,其次去除系统级检校参数中大气延迟分量的影响,然后依据最小二乘平差原理获取最优的系统级检校参数,最后利用最优的系统级检校参数对所有SAR影像进行几何检校处理。论文采用覆盖中国中东部地区的32景GF-3SAR影像进行联合几何检校试验,检校后的SAR影像定位中误差优于9 m。试验结果表明:该方法能够提高GF-3 SAR影像几何检校的精度,验证了其有效性和可行性。

In order to obtain the accurate SAR orthophoto over wide area,it is necessary to modify the geometric parameters for each of the SAR images.However,it is time consuming and laborious to correct each of the SAR images over wide area,which seriously decreased the efficiency of SAR image analysis.Therefore,a wide-area joint geometric calibration method is proposed in this paper.Firstly,the independent system-level calibration parameter is calculated using several SAR images on the basis of R-D model.Secondly,the influence of atmospheric delay component is removed from the system-level calibration parameters.Then,the optimal system-level calibration parameters are obtained based on the least squares adjustment principle.Finally,the other SAR images are corrected using the optimal system-level calibration parameters.In this paper,32 scenes of GF-3 SAR images covering the central and eastern part of China are used for joint geometric calibration.The positioning error of the calibrated SAR images is less than 9 m.The experimental results show that the accuracy of geometric calibration for GF-3 SAR images can be improved by the proposed approach,and thus the effectiveness and feasibility of the proposed approach is demonstrated.