一种基于新型间歇混沌振子的舰船线谱检测方法

A method of detecting line spectrum of ship-radiated noise using a new intermittent chaotic oscillator

为了实现低信噪比下未知频率的舰船辐射线谱的检测,对常规型间歇混沌振子列检测方法进行了改进,提出了一种基于适应步长型间歇混沌振子的信号检测方法.该方法可以只用一个Duffing振子,通过设定一组能够覆盖待测信号所在频段的求解步长序列,实现对未知频率、具有任意初相位的微弱周期信号的搜索检测.为进一步提高系统的弱信号检测性能,分析了Holmes型Duffing方程在不同频率内置策动力下对弱信号灵敏度的差异.综合理论分析和仿真研究结果给出了Duffing振子在内置策动力角频率为0.4 rad/s时对弱信号检测性能最佳,并据此对所采用的Duffing振子进行了优化;仿真结果表明,改进后的Duffing振子的弱信号检测性能提高了12 dB.最后将此方法应用于一组含有舰船辐射线谱的实船数据,结果表明此方法可以实现低信噪比下的未知频率微弱线谱检测.

In order to achieve the effective detection of the line spectrum of ship-radiated noise in low signal-to-noise ratio （SNR）, in this paper we improve the conventional intermittent chaotic oscillator series method, and propose a signal detection method based on the adaptive step intermittent chaotic oscillator. Through setting a sequence of the calculating steps which can cover the frequency band of the signal to be measured, the method can use just 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, we analyze the Holmes Dung equation’s sensitivity for weak signal detection at different internal frequencies. Through theoretical analysis and simulation study, it is found that the Duffing oscillator has the best weak signal detection performance when its internal frequency is 0.4 rad/s. According to this result we optimize the Duffing oscillator. The simulation result shows that the signal detection performance of the improved Duffing oscillator increases 14 dB. In the end, we use the proposed method to detect a set of actual data which contain the ship radiated line spectrum, the result shows that this method could achieve effective detection of the line spectrum in low SNR.