A time-frequency filtering method against interrupted sampling repeater jamming based on histogram energy analysis

Abstract

Interrupted sampling repeater jamming (ISRJ) is a new type of coherent jamming for wideband radar systems. By copying and repeatedly forwarding the radar transmitting signal slice by slice, ISRJ can generate a series of false targets in the range direction, which significantly impairs radar's ability to detect and track targets of interest. Therefore, an advanced time-frequency (TF) filtering method for ISRJ suppression is proposed in this paper. Firstly, the radar received echo signal is transformed into TF domain through short-time Fourier transform (STFT). Secondly, based on the discontinuity and high intensity of ISRJ, the ISRJ contaminated regions can be mapped precisely in the TF image by means of histogram energy analysis and subsequent TF energy accumulation. Finally, these regions are removed by a constructed adaptive filter and the jamming-free pulse compression (PC) results can be obtained. Simulation results reveal that, compared with other competing filtering methods, the proposed method can effectively suppress ISRJ and show better robustness under different circumstances.Keywords-interrupted sampling repeater jamming (ISRJ); short-time Fourier transform (STFT); histogram energy analysis; time-frequency (TF) filtering