Countering self-protection interrupted sampling repeater jammer against chirp radar

Interrupted sampling repeater jammer generates multiple false targets to confuse chirp radar systems. In practical situations, maintaining separation between true target echo and jamming signal is not possible because the jamming pulses and the true target echo are overlapping in both time and frequency domains. A new anti-jamming technique against interrupted sampling jamming of self-protection repeater jammer is proposed without the knowledge of the jamming parameters. The proposed technique is based on fractional Fourier transform that can separate the overlapping true target echo and jamming pulses in the fractional domain, and then the resulting pulses are returned to the time domain, the true target can be easily distinguished from the false ones because the jamming pulses lag behind the true target echo by the jammer's delay. The theoretical analysis and simulation results demonstrate the efficiency and validity of the proposed technique.