Anti-Smeared Spectrum Jamming Technology of Time-Frequency Filtering Combined with LSD

Smeared spectrum (SMSP) jamming generates interference signals that are highly coupled with the radar transmit waveform in the time-frequency domain by changing the FM slope and the number of retransmissions of the intercepted radar waveforms. This paper proposes a time-frequency filtering combined with line segment detector (LSD) anti-SMSP jamming method based on multi-parameter coded waveform. In this method, part of the interference is filteredrFT out in the fractional-order Fourier transform (FrFT) domain, and then the time-frequency points identified as SMSP jamming are discarded by short-time Fourier transform (STFT) in the time-frequency domain, and the target signal is reconstructed using compressive sensing. Finally the LSD detection method based on the SMSP jamming inter-pulse disorder characteristics under the multi-parameter coded waveform is used to further filter out the remaining jamming energy. The simulation results validate the correctness of the theoretical analysis of the proposed method, and compared with the traditional FrFT combined with STFT method, the output jamming to signal ratio of the proposed method is reduced by 10 dB, and the output integral sidelobe ratio is also reduced.