A novel spaceborne SAR wide-swath imaging approach based on Poisson disk-like nonuniform sampling and compressive sensing

Since the range swath width in the conventional single channel spaceborne synthetic aperture radar (SAR) is restricted by the system parameters, there is a trade-off between the azimuth resolution and the swath width in order to satisfy the Nyquist sampling criterion. In this paper, we propose a novel spaceborne SAR wide-swath imaging scheme based on compressive sensing (CS) for the sparse scene. The proposed method designs a Poisson disk-like nonuniform sampling pattern in the azimuth direction, which meets the demand of wider swath by restricting the smallest time interval between any two azimuth samples, with the conventional sampling pattern preserved in the range direction. By a similar way to the processing procedure of spectral analysis (SPECAN) algorithm, the linear range migration correction (RMC) is realized while carrying out range compression, which can meet the demand for focusing with middle level resolution. To reduce the computation load of CS reconstruction, we propose a novel fast reconstruction algorithm based on nonuniform fast Fourier transform (NUFFT), which greatly reduces the computation complexity from O(2MN) to O(4N logN). Experiment results validate the effectiveness of the proposed methods via the point target simulation and the Radarsat-1 raw data processing in F2 mode.