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