The Synthetic Aperture Radar (SAR) altimeter is an active sensor, which is widely used in satellite microwave remote sensing. It can be also used for geophysical localization by evaluating the similarity between the acquired terrain profile and the prior data. However, typical factors, such as the linear assumption of terrain, high variation of the ground elevation, and wide beam width will degrade the positioning accuracy of localization. In this paper, a 3-D localization method combining Delay-Doppler Image (DDI) and spatio-temporal echo similarity is proposed for the SAR altimeter. Firstly, the signal model of the SAR altimeter for DDI imaging is established. Then, the image-matching algorithm for the DDI is developed to achieve localization in the along-track and height directions. Additionally, spatio-temporal similarity is used to deal with cross-track positioning errors. The main advantage of the proposed method is the reliable 3-D localization, especially for extreme radar configurations, such as large undulations and wide beam width. Experimental results based on both simulated and real data validate the method, showing a significant improvement in localization accuracy.

中文翻译：

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SAR 高度计三维定位，结合延迟多普勒图像和时空回波相似性


合成孔径雷达 （SAR） 高度计是一种有源传感器，广泛应用于卫星微波遥感。它还可以通过评估获取的地形剖面与先前数据之间的相似性来用于地球物理定位。然而，地形的线性假设、地面高程的高变化和波束宽度宽等典型因素会降低定位的定位精度。该文针对SAR高度计提出了一种结合延迟多普勒图像（DDI）和时空回波相似性的三维定位方法。首先，建立用于 DDI 成像的 SAR 高度计信号模型;然后，开发 DDI 的图像匹配算法，实现沿轨迹和高度方向的定位。此外，时空相似性用于处理跨轨定位误差。所提出的方法的主要优点是可靠的 3-D 定位，特别是对于极端雷达配置，例如动和宽波束宽度。基于仿真和真实数据的实验结果验证了该方法，表明定位精度得到了显著提高。