Abstract
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.
Highlights
With the growing application of high-speed digital circuit and signal processing in the field of electronic warfare, interrupted-sampling repeater jamming (ISRJ) are becoming important a device
ISRJ based on the digital radio frequency memory (DRFM) technology is a new kind of smart jamming, which aims especially at the linear frequency modulation (LFM) signals with large time bandwidth product [3]
According to the jamming recognition and range gate discrimination results, a set of data corresponding to high effective peaks in the main lobe of the jamming in the one-dimensional range profile is extracted to constitute training data X, which represents an estimate of pure jamming signals and does not contain the target signal
Summary
With the growing application of high-speed digital circuit and signal processing in the field of electronic warfare, interrupted-sampling repeater jamming (ISRJ) are becoming important a device. For distributed array radars which has achieved timefrequency Synchronization [8], main-lobe jamming suppression can be achieved in airspace, time-frequency domain and polarization domain These methods can only be effective under certain circumstances [9]–[11]. We try to suppress main-lobe interrupted-sampling repeater jamming by combining a jamming recognition method based on time–frequency features with a space-domain anti jamming algorithm based on largeaperture distributed radar. After the jamming echo is received by the distributed array, the receiving matrix for the baseband signal after the frequency conversion can be expressed by Equation (8). R is the spacing between the master radar and the jammer and θi is the direction of the jammer
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