Coprime Pulse Trains of Frequency-Modulated for Suppressing Reverberation

Low frequency active sonar is a powerful tool for underwater target detection in the last two decades. The influence of transmitted waveforms on the signal-to-reverberation ratio (SRR) of a low-frequency active sonar is analyzed. We propose a coprime pulse trains of frequency-modulated (CPTFM)waveform to break through the limitation of the ambiguity velocity of the PTFM to decrease the reverberation level significantly. The proposed CPTFM waveform consists of two orthogonal sub-waveforms, whose ambiguity velocities are designed to be low and coprime. The theoretical processing gain of the CPFM pulse over CW, LFM, and PTFM is 17 dB, 25dB, and 10 dB in zone B Simulations show that our proposed CPTFM waveform decreases the reverberation-to-signal ratio (RSR), compared to the conventional waveforms (CW, LFM, and PTFM waveforms). The proposed waveform CPTFM can help better detect the target in the reverberation-limited case.