Interrupted Sampling Repeater Jamming Suppression Based on Ridge Line Filtering Guided by Discrete Points in Near-Field Distributed Coherent Aperture Radar

Traditional monostatic radar significantly enhances signal gain and detection performance through coherent integration of multi-channel echo signals. However, the complex electromagnetic environment created by active deception jamming, which is coherent with the target, consistently prevents monostatic radar from achieving precise target detection and jamming localization, severely degrading the effectiveness of target detection. To address the challenge of separating and locating jamming sources that are spatiotemporally proximate to the target under Interrupted Sampling Repeater Jamming (ISRJ), this paper proposes a jamming suppression method based on Ridge Line Filtering (RLF) guided by discrete points. This method not only achieves jamming suppression but also leverages the spatially distributed architecture of Distributed Coherent Aperture Radar (DCAR) to enable near-field cross-localization of jamming sources. First, RLF guided by high resolution time–frequency (TF) discrete points is constructed at each radar station to separate the target and jamming components. Simultaneously, a jamming amplitude control coefficient is introduced to suppress transient residuals at the segment boundaries of the repeater jamming signals, thereby achieving effective joint jamming suppression. Subsequently, a cross localization method based on the Relative Time Difference of Arrival (RTDOA) between target and jamming signals, combined with the bistatic elliptical range sum, is proposed to calculate the true position of jamming sources relative to DCAR system, achieving near-field jamming cross localization. Finally, simulation analysis and comparison were conducted between the proposed method and current mainstream, highly reliable novel algorithms. The applicability of the proposed method was evaluated in terms of target gain loss and signal to-jamming-plus-noise ratio (SJNR). The results demonstrate the feasibility and effectiveness of the proposed method in jamming suppression, jamming source localization, and target detection.