A Practical Approach Against Interrupted Sampling Repeater Jamming With Phase-Coded Pulse Train Signal

Interrupted sampling repeater jamming (ISRJ) features sound coherence, flexible modulation and fast response capability, thus producing both suppression and deception effects at the radar receiving end, severely degrading the radar detection capability. To address this issue, this paper proposes a Doppler compensation based phase-coded pulse train (PCPT) signal processing method, which can suppress ISRJ while maintaining the coherent accumulation gain. We first formulate the cross-ambiguity function (CAF) of ISRJ and find that the false targets will be distributed parallel along the Doppler axis with a fixed time delay. Taking advantage of this property, we propose an ISRJ identification method based on the two-dimensional adaptive switching cell averaging CFAR (ASCA-CFAR) processor and the mean shift algorithm, followed by a windowing operation to accomplish coarse detection of the true target. On this basis, we further design a Doppler filter with the oblique projection operator to enable fine detection when the clutter or jamming power is high. Multiple simulations show that the proposed method can achieve robust and effective suppression of all types of ISRJ with fluctuating input signal to interference ratio (SIR), high-speed target motion and frequency shift of the jammer, independent of any jamming parameter. In addition, the method is efficient enough to meet the real-time requirements of engineering applications.