SAR image processing for moving target focusing

A novel synthetic aperture radar (SAR) image processing technique has been developed to refocus the ground moving target signature from its smeared response in the SAR image of the stationary ground. The technique implements a matched moving target filter that is derived from the signal history along the target range-Doppler migration path mapped onto the SAR image from its real-space trajectory. The spatial filter is specified by both the apparent target range in the image and the magnitude of the relative target-to-radar velocity. Range dependence may also be eliminated in image filtering by performing the inverse Fourier transform of the SAR image data spectrum after a spatial frequency coordinate transformation