A novel spectrum reconstruction algorithm based on FrFT for multiple azimuth beam SAR

In this paper, we consider the problems of reconstructing the spectrum based on Fractional Fourier Transform (FrFT) from periodic non-uniformly sampled signal in multiple azimuth beams SAR system. First, based on the theory of the paired echoes, the influence of periodic non-uniform sampling for SAR imaging has been derived. Second, signal model of non-uniformly sampling in azimuth direction has been established. Finally, detailed analysis of spectrum reconstruction algorithm in the fractional Fourier domain has been performed. In addition, the simulations are carried out to verify the correctness of the results.