34-43In order to detect line spectrum of ship-radiated noise under the ocean background noise and improve the method of detecting duffing oscillator intermittent chaos, a method of detecting intermittent chaos based on variable step size dual duffing oscillator differential system is proposed. Based on the duffing oscillator, two independent and incompletely coupled duffing oscillators can be differentiated based on the differential principle by using the proposed method, which reduces the computational complexity and makes the timing diagram more intuitive. In order to further improve the detection efficiency and reduce the computational complexity of the system, the author put forward that a sequence of solving steps can be built by using only one duffing oscillator and the method of detecting the unknown frequency signal can be achieved by changing the step size of the system. Simulation results show that compared with the conventional duffing oscillator detection method, the proposed method has improved the SNR (signal-to-noise ratio) by at least 10.6 dB. Comparing with duffing system chaotic oscillator column and double duffing system chaotic oscillator column detection method, the proposed method is most effective in detecting line spectrum of ship-radiated noise
