Exploitation of the COSMO-SkyMed SAR System for GMTI Applications

The focus of this paper is on the exploitation of COSMO-SkyMed spotlight SAR images for Ground Moving Target Indication (GMTI). To this purpose, a two-step processing chain is proposed: the first step performs stationary clutter removal, whereas the second step performs moving targets detection. Both the steps are based on the use of a bank of focusing filters, each one matched to a different relative speed between the radar antenna and the target, here implemented as Chirp Scaling Algorithms in order to keep low the computational burden. The performance of the proposed technique is investigated by applying it to COSMO-SkyMed Single Look Complex spotlight SAR images and compared to theoretical performance: the analysis shows the effectiveness of the proposed technique in suppressing the stationary clutter and providing a high gain in signal to background power ratio, thus allowing subclutter visibility despite the single-channel nature of COSMO-SkyMed data. Moreover, the information provided by the bank is used to estimate the target motion and, by using a knowledge-based approach, relocate in along-track direction the detected movers. The shown results prove the feasibility of a GMTI mode for the COSMO-SkyMed SAR system and more in general for single-channel spaceborne systems.