OPTIMUM LOOK WEIGHTING FOR BURST-MODE AND SCANSAR PROCESSING

Burst-mode and ScanSAR systems record only short pieces of Doppler histories; the energy contained in each echo ensemble and, hence, the intensity in the final burst image (look) depends on the scatterer's position relative to the time of the burst event according to the azimuth antenna pattern, an effect known as scalloping. Most systems employ a burst period short enough that adjacent looks overlap allowing for individual weighting of the looks before summation. The paper introduces a new class of look weighting functions for burst-mode and ScanSAR processing that correct for scalloping while simultaneously keeping the S/N ratio constant over azimuth and maximizing the equivalent number of looks. The achievable radiometric resolution and the sensitivity to Doppler centroid estimation errors are discussed. A 3-look example using ASAR parameters illustrates the proposed weighting functions.