Joint jamming perception and transmit waveform design for anti-interrupted sampling repeater jamming

Interrupted sampling repeater jamming (ISRJ) is a type of intra-pulse coherent jamming based on digital radio frequency memory (DRFM), which has been widely used in jammers in recent years, posing a serious threat to radar detection. Traditional anti-jamming methods are relatively passive, and the jamming suppression performance depends heavily on the accuracy of parameter estimation. Additionally, most waveform design techniques lack the perception of jammer strategies, resulting in performance degradation when suppressing ISRJ. In order to improve radar anti-jamming performance, a scheme for jointing jamming perception and transmit waveform design is developed in this paper. Firstly, bidirectional double-sliding window pulse edge detection and sliding truncated matched filter (STMF) are employed to extract the ISRJ components in the received echo and estimate the relevant parameters accurately. Subsequently, an intra-pulse dual-parameter agile waveform is designed to increase the difference between the target signal and ISRJ. Furthermore, by extracting the interfered sub-pulse segments, filters based on the fractional Fourier transform (FrFT) are constructed to eliminate ISRJ components. Simulation results demonstrate that the proposed method effectively overcomes the ISRJ under different modulation modes with almost no loss of signal energy. When the jamming-to-signal ratio is 9 dB, the method boosts the signal-to-jamming ratio by 30 dB after jamming suppression, ensuring robust target detection.