Refined Time-Frequency Feature Matching for Interrupted Sampling Repeater Jamming Suppression

Interrupted sampling repeater jamming (ISRJ), a common form of coherent jamming, can create numerous false targets surrounding the real target after pulse compression, significantly affecting the target detection ability of radar. To solve this problem, a refined time-frequency (TF) feature matching method based on the intra-pulse frequency agile (IPFA) waveform for ISRJ suppression is proposed. Firstly, the TF template is constructed based on the transmitted waveform TF distribution. The feature information is extracted by shifting the TF template and matching the result of the binarization of the echo TF distribution. Then, the target echo is located according to the feature information extracted from the TF template under different shift times. Next, the time-domain signal is extracted by the inverse TF transformation of the echo TF distribution, which is matched to the template of the target location. The undisturbed signal is extracted to construct the range-dimension filter. Finally, the extracted time domain signal is filtered for jamming suppression and target protection. Simulation results demonstrate that the proposed method performs better ISRJ suppression than conventional methods. Meanwhile, the proposed method effectively mitigates the compound jamming composed of different ISRJs, demonstrating strong resistance to jamming.