Energy function‐guided histogram analysis for interrupted sampling repeater jamming suppression

Interrupted sampling repeater jamming (ISRJ) is a novel intra‐pulse coherent jamming based on digital radio frequency memory (DRFM). By repeatedly sampling and retransmitting the radar transmitting signal fragments, a series of false targets can be formed after pulse compression (PC), posing a severe threat to modern radar systems. Inspired by the energy function method and histogram analysis in image processing, an adaptive time‐frequency (TF) filtering method is proposed in this letter. The ISRJ‐contaminated regions can be accurately determined in the TF image after histogram analysis and subsequent energy accumulation. Guided by the energy function, the proposed method can automatically adjust the intensity threshold in TF image histogram analysis and therefore reveals better robustness compared with other competing methods. Simulations have verified the effectiveness and robustness of the proposed method against ISRJ under various circumstances. This letter presents a time‐frequency (TF) filtering method based on histogram analysis for the suppression of the interrupted sampling repeater jamming (ISRJ). The ISRJ area in the TF image can be accurately located through the histogram analysis and the subsequent energy accumulation. Guided by the energy function, the proposed method can perceive the jamming‐to‐signal ratio (JSR) and can adaptively adjust the energy threshold to locate the ISRJ‐polluted spectrums, which significantly improves the filtering robustness.