Adaptive Digital Beamforming for SAR Imaging in Elevation

Digital beamforming (DBF) spaceborne synthetic aperture radar (SAR) is a promising candidate for achieving high-resolution and ultra-wide-swath (HRWS) images. On reception, digital beamforming technology in elevation can significantly improve the system performance such as its sensitivity, ambiguity level and the output signal-to-noise ratio (SNR) by Scan-On-Receive (SCORE). However, in the wide-swath realistic scenario characterized by mountains and relief, the effect of topographic height would result in a mismatch between the steering direction and the actual direction of arrival and further introduce the SCORE pattern loss (SPL). To solve this problem, this paper presents a comprehensive performance evaluation on SPL and proposes an adaptive DBF processing scheme based on the principle of spectral estimation. Simulation results and real data validate the effectiveness of the processing scheme.