Frequency-Hopping Frequency-Diverse MIMO Radar for Target Detection and Localization Under False-Target Jamming

A novel FH-LFM-FD-MIMO radar system is proposed to detect and localize true targets while suppressing false-target jamming signals. Linear frequency modulated (LFM) pulses are transmitted by a transmit array, with the carrier frequencies optimized to implement frequency-diverse multiple-input-multiple-output (FD-MIMO) and frequency-hopping (FH) schemes. The frequency offsets at all the transmit-array elements are represented as a frequency-diverse (FD) code, which is generated by combining a particle swarm optimization (PSO) algorithm and a rank-order-value (ROV) mapping to enhance the jamming suppression performance. The frequency-hopping (FH) scheme is implemented by applying specific FD codes in different pulse repetition intervals to suppress jamming signals in both frequency domain and spatial domain. The target echoes carrying matched FD code are detected at the receiver, while the false-target jamming signals carrying mismatched FD codes are suppressed. A spotlight response with low sidelobe level is achieved by optimizing the spotlight-range beamforming vector with a second PSO algorithm. After a target is detected, a two-dimensional minimum-variance distortionless response (2D-MVDR) is applied to pinpoint the target with higher precision. A binary integration detection scheme is proposed to enhance the detection performance under more severe jamming condition. The simulation results verify that the proposed FH-LFM-FD-MIMO radar system can increase the output signal-to-jamming-plus-noise ratio (SJNR) by more than 20 dB compared to conventional approaches, acquiring higher probability of detection under constant false alarm rate and enhancing the localization precision.