Duffing混沌振子用于微弱信号检测的研究

针对频率已知的微弱正弦信号幅度和相位检测问题,提出了一种采用Duffing混沌振子作为检测系统的方法。该方法将被测信号作为系统的参数,利用系统参数在临界值附近微小的变化会改变系统输出状态的特性,通过识别系统输出的相轨迹判断输出状态是否改变,根据状态改变所需满足的条件估计信号的参数。给出了实现该方法的主要步骤,并将其运用于高频地波雷达海洋回波信号的检测,与FFT方法所得结果相比,回波多普勒谱的信噪比可提高5 dB,表明了该方法具有更好的检测性能。

Study on the weak sinusoidal signal detection with Duffing chaotic oscillator

To estimate the amplitude and phase of weak sinusoidal signals with known frequency,a method using Duffing chaotic oscillator as the detection system is proposed.In this case,the detected signal is taken as a system parameter.The system's output state changes if the system parameter has a slight change near the threshold.The phase of system's output is recognized to judge whether the output state changes,and the signal parameter is estimated according to the necessary condition for state change.The procedure of detecting weak signals with this method is proposed.The sea echo signal of high frequency ground wave radar(HFGWR) is detected with this method.The result demonstrates this method has a better detection performance by comparing the results with the results got by FFT algorithm,and the signal to noise ratio(SNR) of Doppler spectrum is improved by 5 dB.