Suppression of Moving Target Interference in GB-SAR Deformation Monitoring

Based on the phase differential interferometry technique, ground-based synthetic aperture radar (SAR) can realize high-precision measurement of surface deformation. However, due to the influence of strong scattering moving targets (vehicles, machinery, etc.) in the monitoring scene, moving clutter overlaps with the stationary scene echoes. Different types of motions cause different interferences. During synthetic aperture processing, targets that move significantly in the range direction can easily lead to wide-range defocusing in a fan-ring pattern. Targets that move significantly in the azimuth direction or irregularly in a small area can result in azimuth striping defocusing. These moving targets cause certain areas of the SAR image to lose coherence, severely interfering with the differential interferometric phase of permanent scatterers. This article proposes a method for selecting and compensating interfered azimuth samples based on 1-D range profiles combined with clutter map techniques. First, the clutter map for the current 1-D range profile is generated using historical 1-D range profiles. Based on the amplitude and phase differences between the clutter map and the current 1-D range profile, amplitude and phase thresholds are applied to selected interfered azimuth samples. Then, the interfered azimuth samples are replaced by the corresponding pixels of the clutter map. Finally, the back-projection algorithm is employed to perform imaging. Experimental datasets prove that the method can effectively suppress the interference from moving targets.