🤖 AI Summary
This work addresses the challenge of real-time imaging for unmanned aerial vehicle (UAV)-borne synthetic aperture radar (SAR), where massive data volumes hinder onboard processing. To overcome this limitation, the authors propose Online FISTA, an online sparse reconstruction method that integrates online optimization with compressive sensing-based sparse representation. By incrementally processing echo data and recursively updating only a small set of stored matrices, Online FISTA eliminates the need to buffer the full dataset. This approach substantially reduces both memory consumption and computational complexity, breaking away from conventional offline processing paradigms. As a result, it enables real-time SAR image reconstruction and provides an efficient, low-latency end-to-end processing framework suitable for downstream tasks such as airborne automatic target recognition.
📝 Abstract
With modern defense applications increasingly relying on inexpensive, autonomous drones, lies the major challenge of designing computationally and memory-efficient onboard algorithms to fulfill mission objectives. This challenge is particularly significant in Synthetic Aperture Radar (SAR), where large volumes of data must be collected and processed for downstream tasks. We propose an online reconstruction method, the Online Fast Iterative Shrinkage-Thresholding Algorithm (Online FISTA), which incrementally reconstructs a scene with limited data through sparse coding. Rather than requiring storage of all received signal data, the algorithm recursively updates storage matrices for each iteration, greatly reducing memory demands. Online SAR image reconstruction facilitates more complex downstream tasks, such as Automatic Target Recognition (ATR), in an online manner, resulting in a more versatile and integrated framework compared to existing post-collection reconstruction and ATR approaches.