Integrating Space-time Processing into Time-domain Backprojection Process to Detect and Image Moving Objects

The ability to detect and image moving targets, even surrounded by strong clutter on the ground, makes Synthetic Aperture Radar (SAR) more and more important for Ground Moving Target Indication (GMTI). Moving target detection is most commonly performed by GMTI radars based on antenna array solutions without imaging capability while SAR systems do not facilitate detecting the presence of moving targets in an imaged scene. Moving targets are usually displaced and defocused in a SAR image. Distinguishing them from strong ground clutter requires much effort. Moving target detection by focusing technique appears in some recent publications. The principle of the technique is to focus moving targets with correct Normalized Relative Speed (NRS) while defocus ground clutter, i.e. suppress ground clutter. The technique is suitable to Ultra-wideband (UWB) SAR systems and can be combined with space-time processing techniques, such as Displaced Phase Center Antenna (DPCA) [1], i.e. non-adaptive, and Space Time Adaptive Processing (STAP) [2], for reliable moving target detection and imaging. An example of this combination in dual-channel UWB SAR is presented in [3] where DPCA is considered as a data pre-processing technique. According to this approach, dual-channel SAR data is rst processed by DPCA to suppress ground clutter. The detection by focusing technique is then applied to the data with clutter supression. The goal of this paper is to present the possibility to integrate different space-time taxonomies into the time-domain local backprojection process to detect and image moving targets simultaneously. In this paper, two space-time processing taxonomies, which are considered, are DPCA and STAP. The integration is expected to lighten the strict requirements as well as improve the pratice of these taxonomies. The proposed approach is evaluated by simulations based on the LORA parameters [4].