An Efficient Polyphase Filter Based Resampling Method for Unifying the PRFs in SAR Data

摘要

Variable and higher pulse repetition frequencies (PRFs) are increasinglybeing used to meet the stricter requirements and complexities of currentairborne and spaceborne synthetic aperture radar (SAR) systems associated withhigher resolution and wider area products. POLYPHASE, the proposed resamplingscheme, downsamples and unifies variable PRFs within a single look complex(SLC) SAR acquisition and across a repeat pass sequence of acquisitions down toan effective lower PRF. A sparsity condition of the received SAR data ensuresthat the uniformly resampled data approximates the spectral properties of adecimated densely sampled version of the received SAR data. While experimentsconducted with both synthetically generated and real airborne SAR data showthat POLYPHASE retains comparable performance to the state-of-the-art BLUIscheme in image quality, a polyphase filter-based implementation of POLYPHASEoffers significant computational savings for arbitrary (not necessarilyperiodic) input PRF variations, thus allowing fully on-board, in-place, andreal-time implementation.