False Target Jamming Suppression in Distributed Coherent Aperture Radar

Distributed coherent aperture radar (DCAR) operating in MIMO mode is vulnerable to self-defense dense false target jamming, which closely resembles the true target signal and is therefore difficult to suppress. To address this challenge, based on the difference between the jamming and the target signal in the frequency modulation slope domain, we designed an algorithm combining biorthogonal Fourier transform (BFT) and echo preprocessing, so that there is a significant difference between the jamming and the target signal in the matched filtering (MF) outputs. First, the BFT analysis is employed to separate the echo components corresponding to up-chirp (UC) and down-chirp (DC) before multi-channel MF. Then, echo preprocessing is performed on the separated echoes using reference signals that have different chirp rates. This causes misalignment in the peaks of jamming after MF and enables discrimination between false and real targets. Finally, to prevent the jamming from obtaining higher gain in the process of coherent integration, time-domain filtering is applied before coherent integration. Experimental simulations validate the effectiveness and superiority of the proposed method in terms of jamming suppression.