Spaceborne Staring Spotlight SAR Tomography - A First Demonstration with TerraSAR-X

TL;DR

This paper demonstrates the first use of TerraSAR-X's staring spotlight mode for SAR tomography, showing significant improvements in point cloud density and height accuracy over traditional modes.

Contribution

It introduces tailored processing techniques for staring spotlight SAR tomography and provides the first comparative analysis with sliding spotlight mode.

Findings

Point cloud density increased by a factor of 5.1 to 5.5

Height accuracy improved by approximately 1.7 times

Higher spatial resolution enhances 3D reconstruction quality

Abstract

With the objective of exploiting hardware capabilities and preparing the ground for the next-generation X-band synthetic aperture radar (SAR) missions, TerraSAR-X and TanDEM-X are now able to operate in staring spotlight mode, which is characterized by an increased azimuth resolution of approximately 0.24 m compared to 1.1 m of the conventional sliding spotlight mode. In this paper, we demonstrate for the first time its potential for SAR tomography. To this end, we tailored our interferometric and tomographic processors for the distinctive features of the staring spotlight mode, which will be analyzed accordingly. By means of its higher spatial resolution, the staring spotlight mode will not only lead to a denser point cloud, but also to more accurate height estimates due to the higher signal-to-clutter ratio. As a result of a first comparison between sliding and staring spotlight TomoSAR, the following were observed: 1) the density of the staring spotlight point cloud is approximately 5.1--5.5 times as high; 2) the relative height accuracy of the staring spotlight point cloud is approximately 1.7 times as high.