A Novel Interrupted-Sampling Repeater Jamming Suppression Method Based on Time-Frequency Analysis and Target Sparse Reconstruction

Abstract

Interrupted-sampling repeater jamming (ISRJ) is a new kind of coherent jamming for linear frequency modulation (LFM) signals. Based on digital radio frequency memory (DRFM), ISRJ can generate multiple false target groups by intercepting, storing, and retransmitting radar signal fragments, which significantly affects the postprocessing results of radar systems. Furthermore, due to the fragment interception of ISRJ, ISRJ false targets present a regular and discontinuous time-frequency (TF) distribution in contrast with real targets. Considering this intrinsic property and the coherent nature of ISRJ, this study proposes a new method based on TF analysis and target sparse reconstruction to address the ISRJ suppression issue. In this method, the echo signal is first sparsely represented to obtain both the real and false target positions. Then, according to the acquired target positions, information entropy features of targets are extracted in TF data for subsequent target identification. Finally, guided by the identification result, the real targets can be retained and reconstructed by adaptive filtering in the sparse domain to realize ISRJ suppression. Simulations have validated the effectiveness of the proposed method under various situations.

Countering self-protection interrupted sampling repeater jammer against chirp radar

“…12, the FrFT is inferior to the matched filter by 3 dB in terms of SNR, but it is superior to STFT. Therefore, the anti-jamming techniques based on STFT require high SNR to be effective [18][19][20][21][22][23]. However, the proposed method works well under low SNR.…”

“…Therefore, a band-pass filter (BPF) can be designed to retain the true target signal and suppress the ISRJ signal. In [22], ISRJ suppression issue is addressed by using TF analysis and target sparse reconstruction. In [23], TF analysis result is used to estimate the jamming parameters of slice number and forwarding times to perform jamming suppression.…”

“…In general, short-time Fourier transform (STFT) is applied to perform the TF analysis. Therefore, the previous methods in [18][19][20][21][22][23] are only effective under high signal to noise ratio (SNR). In [24] an anti-jamming method based on designing complementary sequences and receiving filters is proposed.…”