Omega-K Algorithm for Spaceborne Spotlight SAR Imaging

Since the spaceborne spotlight synthetic aperture radar (SAR) has the long slant range and the high altitude, it generates the curved flight path due to the orbit curvature effect and the time delay due to the long round-trip time of the chirp pulse. Thus, to obtain the SAR image with high quality, we extend the omega-K algorithm. First, we convert the curved path into the straight-line path based on the resampling and the rotation of the transmitted-pulse path and the received pulse path. Then, using the modified matched filter and the modified Stolt interpolation based on the principle of the stationary phase, we compensate the phase error induced by the start-stop assumption of the omega-K algorithm.