改进型类Lorenz系统在弱信号检测中的应用

Improved Lorenz-like System for Weak Signal Detection

混沌系统具有一定的抑制噪声能力,且对初始条件敏感。因此在弱信号检测方面,相比于传统检测方法混沌系统具有很大的优势。对一种新型的类Lorenz混沌系统进行了改进,通过加入周期扰动的方法,使得改进后的系统对正弦信号幅值变化更加敏感,以满足检测微弱周期信号的条件。同时,引入了0-1测试算法来进一步确认系统混沌状态的阈值,使得改进后的系统对弱信号振幅检测精度达到10^(-4)V。通过计算状态变量方差,实现了对未知频率信号的检测。仿真结果表明,该混沌系统可检测最低信噪比为-63.01 dB。

Chaotic systems have certain ability to suppress noise and are sensitive to initial conditions.Therefore,in weak signal detection,compared with the traditional detection method chaotic system has a great advantage.In this paper,a new type of Lorenz-like chaotic system is improved,and the improved system is made more sensitive to sinusoidal signal amplitude changes by adding periodic perturbations to meet the conditions of detecting weak periodic signals.At the same time,a 0-1 test algorithm is introduced to further confirm the threshold value of the chaotic state of the system,so that the accuracy of the improved system in detecting the amplitude of weak signals can reach 10^(-4) V.The detection of unknown frequency signals is realized by calculating the variance of the state variables.Simulation results show that the chaotic system can detect the lowest signal-to-noise ratio up to-63.01 dB.