Azimuth Multipulse Complementary Joint Design for SAR Anti-ISRJ and Low Sidelobe

To address the high imaging sidelobe levels associated with existing antijamming waveform design methods for Synthetic Aperture Radar (SAR) under Interrupted-Sampling Repeater Jamming (ISRJ), this paper exploits the degrees of freedom provided by coherent multipulse integration in SAR imaging. Multipulse complementarity enables simultaneous improvement of antijamming capability and low-sidelobe imaging performance. Specifically, an SAR Point Spread Function (PSF) signal model is first established for the azimuth multipulse complementary waveform mode. Based on this model, a nonconvex multiobjective joint optimization framework is developed to maximize jamming suppression and minimize PSF sidelobe levels. To solve this challenging optimization problem, a two-Dimensional Joint Optimization of Complementary waveforms for Anti-ISRJ (2D-JOCA) algorithm is proposed. By adopting an alternating iterative optimization framework, the algorithm decomposes the original problem into two subproblems—waveform and filter optimization—and achieves their cooperative design through closed-form updates. Experimental results demonstrate that, compared with the best results of existing traditional single-waveform antijamming methods, the proposed approach improves the jamming integrated level ratio and jamming peak level ratio by 12.85 and 3.83 dB, respectively, while reducing the integrated sidelobe ratio and peak sidelobe ratio by 24.96 and 11.40 dB, respectively. The proposed approach not only significantly enhances antijamming capability but also effectively suppresses range sidelobes and range–azimuth coupled sidelobes, thereby improving SAR imaging quality in complex electromagnetic interference environments.