Bioinspired Covert Sonar Signal Waveform Design Using Phase Coding of Sperm Whale Clicks for Underwater Sensor Platforms

Low Probability of Intercept and Low Probability of Detection strategies face challenges in enhancing the effective detection range while maintaining covertness. To address this issue, a bio-inspired covert strategy has been proposed and implemented. This approach leverages the original or modified sounds of marine mammals as sonar signals to deceive enemy recognition systems. Based on this strategy, the sperm whale (Physeter macrocephalus)—a widely distributed marine species—was chosen as the biomimetic subject due to its distinctive clicks. However, the sperm whale click signals typically demonstrate superior range resolution, they suffer from limited velocity resolution. To address this limitation, a bio-inspired covert sonar signal waveform design approach using phase coding of sperm whale clicks was developed, mimicking the intrinsic pseudo-periodic modulation patterns of click pulse trains. The proposed method features a simple construction process, requiring only minimal modifications to the original signal, thus ensuring excellent covertness. This study also analyzes critical parameters influencing signal detection performance. Simulation and experimental results demonstrate the superiority of the proposed method in terms of detection effectiveness and covertness.