As current airborne and spaceborne synthetic aperture radar (SAR) systems aim to produce higher resolution and wider area products, their associated complexities call for handling stricter requirements. Variable and higher pulse repetition frequencies (PRFs) are increasingly being used to achieve these demanding requirements in modern radar systems. This paper presents a resampling scheme capable of unifying and downsampling variable PRFs within a single look complex (SLC) SAR acquisition and across a repeat pass sequence of acquisitions down to an effective lower PRF through the use of polyphase filters. To evaluate the performance of this resampling scheme, we use airborne SAR raw data with variable PRFs. The data were processed with and without the proposed resampling method as part of the flow of the imaging algorithm. Significant improvement in the point spread function (PSF) measurement and the visible image quality after rate conversion and normalization justify the theoretical basis of the proposed method and the benefits it can provide in application scenarios.
['Yoangel Torres', 'Kamal Premaratne', 'Falk Amelung', 'Shimon Wdowinski']
An Efficient Polyphase Filter Based Resampling Method for Unifying the PRFs in SAR Data