A Method For Detection Line Spectrum Of Ship-radiated Noise Using A New Intermittent Chaotic Oscillator

In order to achieve the effective detection of the line spectrum of ship-radiated noise in low SNR, this paper improves the conventional intermittent chaotic oscillator series method,and proposes a signal detection method based on the adaptive step intermittent chaotic oscillator. Through setting a sequence of the calculating step which can covering the frequency band of the signal to be measured, the method can just use one Duffing oscillator to accomplish the searching detection for the weak signal with unknown frequency. In order to further improve the weak signal detection performance, the paper analyzes the Holmes-Duffing equation's sensitivity for weak signal detection in different internal frequency. Through theoretical analysis and simulation study,finding the Duffing oscillator has the best weak signal detection performance when its internal frequency is 0.4rad/s.According this result the paper made optimization for the Duffing oscillator, the simulation result shows that the signal detection performance of the improved Duffing oscillator increases 12dB. In the end applying the method to detect a set of actual data which contains the ship radiated line spectrum, the result showed this method could achieve effective detection for the line spectrum, besides it is also more accurate and easier to apply.