A comparison of displaced phase centre antenna and along-track interferometry techniques for RADARSAT-2 ground moving target indication

Canada's RADARSAT-2 commercial synthetic aperture radar (SAR) satellite will have an experimental mode that will permit ground moving target indication (GMTI) measurements to be made. In this mode of operation, the radar antenna is partitioned into two subapertures that sequentially observe the scene of interest from the same point in space. Two of the GMTI processing approaches currently being explored are examined in this paper. One utilizes the displaced phase centre antenna (DPCA) clutter-cancellation technique to provide subclutter visibility for dim, slowly moving objects. The other is based on the along-track interferometry (ATI) technique, in which magnitude and phase information of the targets' interferograms are exploited to extract them from the background clutter. In this paper the performance of each processor is examined for three RADARSAT-2 slant-range resolutions: 12.5, 3.0, and 1.5 m. The study focuses on the influence of SAR resolution cell size on the GMTI processor performance. Results indicate that, as SAR slant-range resolution increases, the SAR ATI improves in performance, whereas the SAR DPCA does not.