Department of Surveying and Geomatics Engineering, University of Tehran, Tehran 14395-515, Iran.
Sensors (Basel). 2013 Sep 9;13(9):12030-43. doi: 10.3390/s130912030.
The Rational Function Model (RFM) has been widely used as an alternative to rigorous sensor models of high-resolution optical imagery in photogrammetry and remote sensing geometric processing. However, not much work has been done to evaluate the applicability of the RF model for Synthetic Aperture Radar (SAR) image processing. This paper investigates how to generate a Rational Polynomial Coefficient (RPC) for high-resolution TerraSAR-X imagery using an independent approach. The experimental results demonstrate that the RFM obtained using the independent approach fits the Range-Doppler physical sensor model with an accuracy of greater than 10-3 pixel. Because independent RPCs indicate absolute errors in geolocation, two methods can be used to improve the geometric accuracy of the RFM. In the first method, Ground Control Points (GCPs) are used to update SAR sensor orientation parameters, and the RPCs are calculated using the updated parameters. Our experiment demonstrates that by using three control points in the corners of the image, an accuracy of 0.69 pixels in range and 0.88 pixels in the azimuth direction is achieved. For the second method, we tested the use of an affine model for refining RPCs. In this case, by applying four GCPs in the corners of the image, the accuracy reached 0.75 pixels in range and 0.82 pixels in the azimuth direction.
有理函数模型（RFM）已被广泛应用于摄影测量和遥感几何处理中，作为高分辨率光学图像严格传感器模型的替代方法。然而，在合成孔径雷达（SAR）图像处理中，针对 RF 模型的适用性评估工作却很少。本文研究了如何使用独立方法为高分辨率 TerraSAR-X 图像生成有理多项式系数（RPC）。实验结果表明，使用独立方法获得的 RFM 与距离多普勒物理传感器模型的拟合精度大于 10-3 像素。由于独立 RPC 表示地理位置的绝对误差，因此可以使用两种方法来提高 RFM 的几何精度。第一种方法是使用地面控制点（GCP）更新 SAR 传感器方位参数，并使用更新后的参数计算 RPC。我们的实验表明，通过在图像角上使用三个控制点，可以实现 0.69 像素的距离精度和 0.88 像素的方位精度。对于第二种方法，我们测试了使用仿射模型来细化 RPC。在这种情况下，通过在图像角上使用四个 GCP，可以实现 0.75 像素的距离精度和 0.82 像素的方位精度。
