On a Dual PRI Pulse Sequence Mode for High-Resolution Wide-Swath SAR Imaging

High-resolution and wide swath are known to be inherently incompatible requirements for spaceborne synthetic aperture radar (SAR) imaging systems. Extensive research shows that advanced instrument modes and architectures employing multiple receive channels in elevation and/or azimuth represent a feasible solution for this conflict. Currently, high SAR performance alternatives include ScanSAR systems with multiple channels in azimuth and Staggered-SAR systems with Scan-on-Receive (SCORE). The first are subject to Doppler spectral gaps and the undesirable scalloping effect. Staggered-SAR shows the considerable advantage of a complete Doppler spectrum, but at the cost of non-uniform sampling. This drives up the sampling rate and as a consequence the complexity, as on-board processing becomes necessary for data-rate reduction. This paper discusses a method to achieve high-resolution imaging using complementary coverage of a wide swath with two (interleaved) constant-PRI sequences, thus without incurring Doppler spectral gaps but also without paying the system-complexity penalty of irregular sampling.