2D-ISRJ Suppression in Synthetic Aperture Radar Data via a Three-Step Approach: Detection, Location, and Mitigation

Synthetic aperture radar (SAR), renowned for its all-day all-weather operation and strong penetration, has been extensively utilized in many fields. However, SAR has been exposed to complex electromagnetic environment and is prone to being affected by various types of jamming. Among them, the 2-D intermittent sampling repeater jamming (2D-ISRJ), as a currently representative and newer jamming type, has adverse effects on the performance of SAR to a certain extent. However, existing 2D-ISRJ suppression research is relatively scarce, and traditional time–frequency methods suffer from inaccurate jamming parameter estimation, thus weakening the suppression effect. In this article, a three-step approach is proposed to tackle the 2D-ISRJ problem. In the proposed approach, the first step is to detect 2D-ISRJ, which is based on the variance sequence from short-time Fourier transform and the double sliding window differential extremum location algorithm (DSWDELA). The second step is to locate 2D-ISRJ, which is based on the jamming-containing pulses and the DSWDELA. The third step is to mitigate 2D-ISRJ, which is achieved by designing a time–frequency domain (TFD) filter based on the time mapping relationship between the time domain and the TFD to notch 2D-ISRJ and recovering the notched signal based on a Gaussian kernel function. Experimental result indicates that when a jamming-to-signal ratio is greater than 6 dB, the proposed method demonstrates high effectiveness in typical 2D-ISRJ types.