High-Resolution and Wide-Swath SAR Imaging via Poisson Disk Sampling and Iterative Shrinkage Thresholding

Abstract

Since the width of range swath of synthetic aperture radar (SAR) is restricted by the pulse repetition frequency, there exists a tradeoff between the azimuth resolution and the range swath width. As a result, conventional SAR imaging methods based on the Nyquist sampling theorem can hardly achieve the high resolution and wide swath simultaneously. In this paper, we propose an algorithm of high-resolution and wide-swath SAR imaging based on the combination of Poisson disk sampling and iterative shrinkage thresholding. Poisson disk sampling adopted in the azimuth direction can ensure that the interval between any two adjacent pulses is longer than the Nyquist sampling interval, which provides the potential to widen SAR imaging swath in the range direction. The imaging formation is carried out by performing the inverse operator of the chirp scaling algorithm and the shrinkage thresholding in an iterative fashion. Compared with the existing SAR imaging methods, the proposed method can realize high-resolution and wide-swath SAR imaging simultaneously with affordable computational cost. Simulations and experiments on real SAR data demonstrate the effectiveness of the proposed method.