Omega-k quadtree UWB SAR focusing

A variation on the quadtree algorithm for ultra-wideband, wide-angle (UWB-WA) SAR imaging that uses the ω-k algorithm for final stage focusing is introduced. Several signal processing techniques appropriate to the requirements of UWB-WA SAR, and that prevent errors and artifacts in the ω-k focusing are reviewed. These techniques include spatial and temporal shifts for spotlight data, elimination of ghost targets, and adjustments needed to account for the virtual sampling of the quadtree algorithm. In order to justify these techniques, a simple Fourier-based model of the imaging problem appropriate to UWB-WA SAR is presented