Repeat radar jammer suppression for a colocated MIMO radar

The digital radio frequency memory repeat jammer, which replicates transmit signals and transmits them back to a radar receiver to mimic real targets, is a notably efficient electronic countermeasure device. It has been pointed out that the colocated multiple-input multiple-output (MIMO) radar has an additional advantage in combatting with repeat jammers whose amplifiers operate in the saturation mode and thus can only transmit constant-modulus waveforms, because the amplitude modulation of angular waveforms is difficult to simulate for them. Two waveform design criteria are presented, and both suppress a mutual correlation between angular waveforms and corresponding constant-modulus jamming signals. The two approaches differ on whether the receive beamforming operation is considered. Numerical results validate that the two approaches can both efficiently suppress the mutual correlation and that the second approach outperforms the first approach in terms of the peak sidelobe level.