An Active Jamming Method Against ISAR Based on Periodic Binary Phase Modulation

Phase modulation technique is of great potential for generating jamming signal in electronic countermeasures. It is still a difficulty to devise a kind of jamming signal capable of generating both false targets deception jamming and barrage jamming. Attentions must be paid to phase modulation patterns and phase values. Inspired by scatter-wave jamming and phase modulation, an active jamming technique against inverse synthetic aperture radar (ISAR) is proposed based on periodic binary phase modulation in this paper. By imposing the periodic binary phase value (0 or π) onto the intercepted radar signal, the frequency properties of radar signal are changed, which result in the corresponding changes on the target echo. Accordingly, the imaging results are reformatted comparing with the target image. Radar pulses are sampled and phase-modulated in the fast time domain as well as the slow time domain, and then the jamming pulses are retransmitted to the target. After ISAR imaging, the false target images are induced. The principle and process of phase modulation are studied in detail. Then, the imaging model of jamming signal is established and the analysis of jamming effects are carried out. The simulation results with single scattering point and real data experiments with a ship show that both deception jamming and barrage jamming can be obtained. The theoretical analysis and simulation results prove the validity of the active jamming technique.