High resolution imaging of ground moving targets for FMCW SAR based on relative motion

Frequency-Modulated Continuous-Wave Synthetic Aperture Radar (FMCW SAR) is a promising compact remote imaging sensor. A refocusing method of ground moving targets for FMCW SAR is derived considering the moving target range cell walk within a long coherent processing interval. To discriminate the target optimally, the concept of relative motion is utilized. By searching a relative factor, moving targets can be refocused like a stationary target with high resolution using modified SAR imaging algorithm. For fast moving targets with Doppler ambiguity, besides the relative factor, the direction of the relative velocity or an established equivalent squint angle is taken into account in this paper. The detection of the targets and motion parameter estimation are performed at the same time. The maximum output corresponds to the best matched parameters.