Abstract:To enhance the capability of the synthetic aperture radar (SAR) system in anti-retransmission deception jamming, a technique for waveform design and optimization based on non-linear frequency modulation (NLFM) signals is proposed. This approach utilizes autonomous transmit-receive strategies to optimize waveform groups, ensuring that the waveforms emitted during agile transmission are mutually orthogonal. This enables effective suppression of retransmission deception jamming in complex environments. Firstly, the mechanism of retransmission deception jamming in SAR systems is analyzed, and the rationality and effectiveness of waveform agile transmission methods are discussed. A method for anti-jamming using orthogonal waveform design is then proposed. Secondly, NLFM signals are generated using the segmented function method, and the waveform group of NLFM signals is optimized based on the Lagrange algorithm in conjunction with the genetic algorithm. Finally, simulation experiments are conducted to verify the effectiveness of the optimized waveform set designed by the proposed method in countering retransmission deception jamming in SAR systems. The results show that when NLFM waveforms are generated by the segmented function method and optimized for orthogonality using the Lagrange genetic algorithm with appropriate jamming forwarding delays, they improve the mainlobe width and peak sidelobe ratio of the waveforms. This enhancement in orthogonality of agile waveforms leads to improved waveform quality.