A Radargrammetry Algorithm for High-Resolution SAR Satellite Constellations

The recent development of commercial high-resolution synthetic aperture radar (SAR) satellite constellations provides the opportunity to acquire SAR data with resolutions of 1 m or less with a high temporal repeat rate. One potential use of this technology is the construction of high-resolution digital surface models (DSMs) for use in monitoring rapid topographic changes, for example, coastal erosion caused by a hurricane landfall. Here, we describe a stereo radargrammetry algorithm that is well suited to imagery collected from both parallel and crossing orbit geometries. An epipolar geometry is described to enable its efficient operation. An open-source implementation of the algorithm has been published. DSMs from three coastal test sites with varying terrain properties and surface features are generated from SAR imagery collected in a variety of imaging modes. The DSMs generated from all configurations demonstrate good agreement with reference elevation models, even in low relief regions, with comparable performance for parallel and crossing orbits. A comparison of a radargrammetric DSM to a lidar surface model shows the algorithm can accurately measure heights in vegetated and nonvegetated coastal areas, which may be useful for damage assessment and change detection tasks following landfall.