Suppression of Deceptive Jamming in SAR Using Amplitude-Dithered Signals

Deceptive jamming poses a significant threat to synthetic aperture radar (SAR) systems due to its low power requirements, flexibility, and high-fidelity false target generation capabilities. Existing waveform-agility-based countermeasures often rely on the critical assumption that jammers cannot estimate the transmitted signal parameters within the current pulse repetition interval due to digital radio frequency memory processing latency. However, advancements in jammer technologies challenge this assumption, potentially compromising the effectiveness of these countermeasures. To address this issue, we propose an amplitude-dithered waveform technique that eliminates dependence on jammer delay assumptions. Specifically, the transmitted signal employs randomized amplitude dithering in the time domain, which prevents jammers from accurately estimating the signal amplitude and thereby reduces coherence between the jamming and echo signals. The proposed approach significantly mitigates sensitivity to signal orthogonality constraints, enhancing deceptive jamming suppression performance against advanced real-time deceptive jamming. Furthermore, we provide a comprehensive theoretical framework by deriving the ambiguity and cross-ambiguity functions for the proposed schemes. The effectiveness of our approach is validated through extensive simulations, demonstrating superior jamming suppression performance in both point target scenarios and complex scene imaging environments. The experimental results align closely with theoretical predictions, further confirming the practical viability of our approach for robust SAR imaging in hostile environments.