Weak Signal Detection Method Under Lévy Noise Based on Duffing Chaotic System and Fast Phase Judgment

As modern scientific instrument technology improves by leaps and bounds, the noise reduction technology of underwater vehicle is constantly improved. The signal-to-noise ratio(SNR) received by the underwater acoustic collection system in complex marine noise environments is decreasing. Since the 1960s, the noise level of submarines has been reduced by 36dB. Traditional spectrum estimation and wavelet analysis methods are no longer able to meet the requirements. The Duffing chaotic oscillator(DCO) method has low SNR detection threshold and is insensitive to noise, making it suitable for underwater target detection with complex noise signals. However, existing DCO methods have complex system phase determination methods and are mostly validated using Gaussian noise. This paper presents a method based on FFT to quickly determine the phase state of DCO under the condition of weak single frequency signal. By using Lévy noise to simulate underwater noise background, the detection SNR can reach -15.7dB. Theoretically, the phase state determination can be completed in as fast as 35 seconds. In the case of large data volume, it has great engineering application advantages.