Interrupted sampling repeater jamming suppression method based on time-frequency analysis combined with SVM

Interrupted sampling repeater jamming (ISRJ) is an intra-pulse coherent jamming, seriously impairing the effectiveness of pulse compression radar. To address this issue, this paper proposes an ISRJ suppression method based on time-frequency analysis combined with support vector machine (SVM), on the basis of the different time-frequency distributions of ISRJ signals and target echo signals after pulse compression. Firstly, the radar received signal is transformed to the time-frequency domain using short-time Fourier transform (STFT) with Gaussian window, improving the resolution of the signal in the time-frequency domain; Secondly, the optimal classification hyperplane is obtained through training the random sample set offline, enabling the intelligent identification and classification of the target and the jamming signal; Then, the Z-score method is applied to eliminate outlier points caused by high jamming sidelobes near the target’s pulse-compressed peaks, further enabling the jamming suppression effectiveness; Finally, Inverse short-time Fourier transform (ISTFT) is performed on the processed time-frequency matrix to reconstruct the target’s pulse-compressed result after jamming suppression. Simulation experiments have validated the high robustness of the proposed method, demonstrating its enhanced jamming suppression performance compared to conventional methods.