Improved Linear PRI Design Strategy for HRWS Continuous Spaceborne SAR Imaging

In spaceborne synthetic aperture radar (SAR) imaging, pulse repetition interval (PRI) variation technique can be used to change the position of gaps caused by transmission blockage, enabling ultrawide continuous swath SAR imaging. In particular, linear fast PRI change stands out for its ability to directly control gap positions. However, when higher resolution is required, existing linear fast PRI design strategy poses a potential risk of gap overlap, further degrading imaging quality. To tackle this problem, this letter proposes an improved linear fast PRI change design strategy for high-resolution wide-swath (HRWS) continuous SAR imaging. In the improved design strategy, a feasible region for PRI design is developed to ensure that azimuth samples are never continuously lost. Subsequently, the design strategy of more elaborated PRI sequence is improved by expanding the feasible region, which increases the flexibility of system design and improves the range ambiguity to signal ratio (RASR) performance of SAR. Finally, simulation results demonstrate the advancement of the proposed strategy, with the worst RASR of the SAR system improving by 6 dB in the given example.