A novel spectrum reconstruction algorithm for high resolution and wide swath space-borne SAR

The displaced phase center multi-beam technique enables a wide-swath Synthetic Aperture Radar (SAR) with high azimuth resolution. However, the pulse repetition frequency, sensor velocity and antenna size underlie a stringent timing requirement and any deviation will result in a non-uniform sampling in space domain. The paper derives an innovative frequency domain reconstruction algorithm, which enables a recovery of the unambiguous Doppler spectrum also in case of a non-uniform sampling. Theoretical analysis shows the swath and resolution can be simultaneously increased M (the number of sub-aperture) times. The potential of the algorithm when applied to the DPC SAR systems with 7 receive sub-apertures is demonstrated and the spurious image from the non-uniform sampling is suppressed to below -60dB. In addition, the fast algorithm of reconstruction in frequency domain is proposed.