Altitude-Adaptive Coregistration for Differential SAR Tomography

Abstract

SAR tomography is predominantly realized through separate inversion of the 1-D vectors of SLC values at each range-azimuth pixel of a coregistered stack of multi-baseline SAR acquisitions. This approach relies on the simplification that, after coregistration, a scatterer will appear in the same position throughout the stack, regardless of its elevation. Although this is often reasonably accurate, for scenarios with large spatial baselines and elevation extents as well as high range resolutions, this underlying assumption can be significantly violated, resulting in impaired inversions. We analyze the impact of this effect and present a compensation method that we verify with simulated data. Furthermore, we discuss why this approach is particularly suitable and relevant for differential tomography in mountainous regions.