Exploitation of Geometric Diversity for High Resolution Ultrahigh Frequency (UHF) Synthetic Aperture Radar (SAR) Imaging

The SET Team proposes to develop advanced 3-D SAR image formation techniques using Ultra High Frequency Radar that effectively exploit a circular collect imaging scenario. The SAR system orbits a fixed region of interest and collects spot-mode radar data with a sweep in elevation. The SET design will use (1) compressive sensing imaging approaches to reduce sidelobes, mitigate spurious RFI responses in the 3-D SAR imagery, and enhance resolution - all artifacts of UHF sensing-, and (2) wide-angle SAR imaging techniques to exploit the circular collect azimuth sweep for improving image resolution. SET will use the pre-existing circle collected spotlight mode UHF SAR US Army TRACER dataset to support Phase 1 research. The SET design will reflect the need for near real-time, surface-penetrating 3D visualization in warfare scenarios by performing a feasibility and sensitivity study for two collection CONOPS for a 3D building mapping via exterior RF probing application: (1) the feasibility of a single-pass 3-D imaging capability utilizing a flight path that sweeps in azimuth while gradually varying elevation, and, comparatively, (2) the expected resolution gain that can be achieved by multi-pass collections. BENEFIT: The capability to detect buried IEDs, perform 3D building mapping by exterior RF probing, or through foliage target detection in day/night conditions is critically needed in the modern warfare scenario. All these examples require surface penetrating sensing, an attribute of UHF radar, and a 3D imaging capability that allows for the resolution of multiple height scatterers in a resolution bin, an attribute of 3D tomography.