Suppression method for main-lobe interrupted sampling repeater jamming in distributed radar

Main-lobe interrupted-sampling repeater jamming is a coherent type of interference. As this interference is injected through the main lobe of the antenna into a radar system, the interference heavily degrades the performance of the radar system. In this paper, we propose an anti-jamming method based on minimum variance distortionless response (MVDR) that estimates a covariance matrix by obtaining small-sample pure jamming signals through jamming recognition. Time-frequency analysis is performed in the one-dimensional range profile of the pulse-compressed radar echo, and the snapshot sampling of pure jamming is achieved by searching the range gates for the target and the jamming in a two-dimensional range-frequency graph considering the time-frequency differences between the target and jamming signals. Assuming that the available data of snapshot sampling are insufficient, a covariance matrix for pure jamming is reconstructed through an iterative adaptive approach (IAA) and used as the training sample for the MVDR beamformer to suppress main-lobe interrupted-sampling repeater jamming. Finally, the method is validated by comparing the simulation results with the measured results.