A method against interrupted-sampling repeater jamming for frequency-agile radars based on complex variational mode decomposition

By intercepting and intermittently forwarding radar-transmitted signals, jammers can rapidly generate Interrupted Sampling Repeater Jamming (ISRJ). When true and false targets are highly overlapped in the time domain, existing radar jamming suppression methods tend to result in significant residual interference signals. To address this issue, this paper proposes a jamming suppression method based on frequency-agile waveforms and Complex Variational Mode Decomposition (CVMD). Specifically, a nonlinear stretching function is first designed according to the energy distribution of jamming in the echo, enabling the extraction of jammed echo segments, which are then decomposed via CVMD to achieve adaptive separation of different frequency components. The separation of target and jamming signals is realized by exploiting the intra-pulse carrier frequency offset characteristic of the jamming. Finally, target energy integration is accomplished through segmented pulse compression. Simulation results demonstrate that the proposed method effectively counteracts various forms of ISRJ, maintains stable suppression performance even under high jamming-to-signal ratio conditions, and significantly enhances radar jamming resistance.