Direct Wave Suppression Technology Based on De-slope Filtering and Sparse Recovery of Integrated Detection and Jamming System

‍ ‍Through the integrated design of waveforms， the integrated detection and jamming system used jamming signals without typical radar signal characteristics to detect. The signals could share resources such as waveform， frequency， time， and aperture， which greatly improved the comprehensive utilization rate of system resources. However， in order to achieve effective interference， the integrated detection and jamming waveform would overlap with the other side’s radar signal in the frequency band， and the detection echo received by the integrated equipment would be affected by the strong direct wave caused by the other side’s radar transmission signal. Considering the scenario of the confrontation between the integrated detection and jamming system and the linear frequency modulation （LFM） radar， this paper proposed two methods of direct wave suppression algorithm （de-slope and frequency-domain filtering and sparse recovery）. In the first method， the echo de-slope function could be constructed by the direct LFM slope of the other side which could be estimated by fractional Fourier transform （FRFT）. After the direct wave component was converted into a point-frequency signal， it could be filtered by the frequency filtering. In the second method， the de-slope and frequency-domain filtering method was taken as the preprocessing step. Aiming at the problem of echo energy loss caused by de-slope filtering when the direct wave power was strong， the loss signal was restored by using the sparse recovery method. The detection capability of the integrated detection and jamming system had been further improved. The feasibility of the proposed algorithm is verified by simulation and results of measured data processing.