Towards Drone-Based Single-Pass Across-Track SAR Interferometry

Abstract

Drone-based SAR interferometry (InSAR) enables the generation of high-quality digital elevation models (DEMs), whichrequires not only a wide bandwidth but also interferometric baselines of several meters when operating at frequencies between the L and X bands. While in the case of repeat-pass InSAR signal processing is challenging due to non-linear trajectories and low flight altitudes, multi-platform, single-pass acquisition geometries are in addition limited by flight safety constraints that make it difficult to obtain feasible interferometric parameters, e.g., height of ambiguity or low baseline decorrelation. In this work, we present a repeat-pass InSAR experiment conducted over an area with notable topography, demonstrating the capability to generate high-quality DEMs in a general scenario with topographic variations of the order of the drone flight height. Furthermore, we investigate potential flight formations for multi-platform, single-pass InSAR, showing that parallel and along-track baselines can be introduced to achieve viable InSAR parameters without notable degradation on the interferometric coherence. The investigated aspects are paramount not only to effectively perform single-pass InSAR acquisitions, but also to conduct demonstrations of further multi-baseline SAR concepts achieving parameters representative of spaceborne systems.