用RPC替代星载SAR严密成像几何模型的试验与分析

Analysis and Test of the Substitutability of the RPC Model for the Rigorous Sensor Model of Spaceborne SAR Imagery

将推扫式光学卫星遥感影像与雷达影像的成像特点进行比照和分析,从理论上阐述RPC模型拟合SAR严密几何成像的可行性。然后,介绍求解RPC参数的基本方法和流程。在实验部分,采用不同分辨率的SAR数据作为实验数据,计算分母不同且为三阶的RPC模型拟合严密成像几何模型的残差。实验结果证明,无论对高分辨SAR影像或是中低分辨率的SAR影像,RPC模型拟合严密几何成像模型都达到了较高的精度,可以取代严密成像几何模型进行摄影测量处理。

The imaging characteristics of push-broom scanner imagery are compared with radar imagery,and the applicability of fitting SAR rigorous geometric imaging by the RPC model are analyzed in theory.Then the basic approach and flows of calculating the RPC＇s coefficients are introduced.In the experimental verification part of this paper,spaceborne SAR images are used with different resolutions to calculate the RMS errors of the 3rd order RPC with unequal denominator for fitting the rigorous sensor models.The experimental results show that compared with the rigorous sensor model,the RPC model has no discernable loss of accuracy not only for the high resolution SAR imagery but also for the middle or low resolution SAR imagery,i.e.,the RPC model can replace the rigorous sensor model for photogrammetric processing.