Digital beamforming in elevation for spaceborne HRWS SAR based on sparse DOA estimation

Abstract

ABSTRACTA digital beamforming (DBF) algorithm in elevation for spaceborne high-resolution and wide-swath synthetic aperture radar (SAR) systems is presented. According to the imaging geometry, a generalized signal model for SAR systems of multiple elevation channels is studied. The signals received by the channels are regarded as that coming from different direction-of-arrive (DOA) angles. Then, the key procedure for DBF is transformed to DOA estimation. Considering the sparsity of the received signals in spatial domain, the sparse-based DOA estimation algorithm is adopted. After obtaining the DOA angles, the weighted vector for DBF is achieved. Compared to the conventional algorithms, the proposed algorithm has no requirement for the number of snapshots and is more robust to signal-to-noise ratio. Finally, the effectiveness of the proposed algorithm is confirmed in simulations.