An ISRJ suppression method based on time-frequency analysis combined with frequency-dimension projection

To effectively suppress interrupted sampling repeater jamming (ISRJ), this paper proposes an ISRJ suppression method based on time-frequency analysis combined with frequency-dimension projection, leveraging the distinct time-frequency amplitude responses of target echo signals and ISRJ signals after dechirping. Firstly, a bidirectional sliding window detection method is used to locate the echo pulses. Subsequently, the time-frequency matrix of the localized region is projected onto the frequency dimension, and a differential method is applied to preliminarily identify peak points of jamming and targets. Then, the standard deviation from statistics is utilized as a discriminant metric to distinguish between target and jamming peaks, followed by the construction of a time-frequency filter for jamming suppression. Finally, performing inverse Short-Time Fourier Transform (STFT) processing on the jamming-suppressed time-frequency matrix to obtain the final suppression results. Simulation experiments demonstrate the proposed algorithm exhibiting superior jamming suppression performance, particularly addressing the limitations of traditional methods under low signal-to-noise ratio (SNR) conditions.