ISRJ Rejection With MIMO Radar Using Space–Time Complex Modulation in Multijamming Scenario

Interrupted sampling repeater jamming (ISRJ) is an advanced coherent jamming with both suppression and deception effects. Effective countermeasures have been proposed, but most of these methods only consider ISRJ suppression in the case of single jamming or multiple jammings with the same parameters. In this article, we propose a space–time complex modulation (STCM) technique based on colocated multiple-input multiple-output (MIMO) radar to cope with the threat of multiple ISRJs with different parameters. The STCM refers to encoding the carrier frequency of the signal transmitted by each array element and randomly encoding the initial phase of each pulse emitted by each array element. This modulation method can separate the ISRJ mixed with the target in the transmitting angular frequency-range (TAFR) spectrum. Using this characteristic, we study the waveform parameter design criterion for the sufficient separation of targets and ISRJs. Moreover, the detailed STCM-MIMO waveform processing method is developed for ISRJ suppression. Simulation results are provided to prove the effectiveness of the proposed modulation method in ISRJ separation and the significant advantage of the proposed ISRJ suppression method over existing methods in the presence of multiple jammings.