Multi-Static Synthetic Aperture Radar for Earth Monitoring: Challenges, Innovative Solutions, and Demonstrations Using Swarms of Drones

Spaceborne synthetic aperture radar (SAR) is an essential tool for Earth observation applications. By combining multiple SAR images taken from different viewing angles, precise digital elevation models and high-resolution tomograms can be created, revealing the three-dimensional structure of vegetation, ice, and dry soil. Currently, such images are typically acquired sequentially, impacting product quality and limiting our ability to monitor rapid changes effectively. Multi-static SAR systems bring new possibilities by enabling the simultaneous collection of all necessary data, promising more effective and robust planetary monitoring. However, a significant challenge lies in developing multi-static concepts capable of generating high-quality digital elevation models and tomograms from sets of noisy and undersampled radar data acquired by clusters of smallsats with compact antenna apertures. To address this, swarms of drones equipped with radars and localization systems offer an affordable option for testing multi-static concepts and acquiring data with sub-hour temporal resolution