Unambiguous SAR imaging from non-uniform sampling with simple fractional Fourier transform

The displaced phase centre multiple azimuth beams (DPC-MAB) synthetic aperture radar (SAR) can realize wide swath imaging with high azimuth resolution, but it has strict requirement on the pulse repetition frequency (PRF). When actual PRF deviates from the ideal PRF, non-uniform azimuth sampling will arise and then seriously interfere with SAR imaging. This paper proposes a novel reconstruction method associated with the simple fractional Fourier transform, which can enable unambiguous SAR imaging in the case of non-uniform azimuth sampling. Compared with the traditional spectrum reconstruction method, the proposed method has better performance and can realize unambiguous SAR imaging even in the case of undersampling. Experiments with simulated and real data verify the efficiency of the proposed method.