噪声对混沌系统检测性能的影响

Influence of Noise on Detection Performance of Chaotic System

理论上,混沌系统具有对噪声不敏感,而对与其内置信号同频率的信号敏感的特点,据此可将混沌系统应用于微弱信号检测。但在实际仿真中发现:当系统处于混沌临界状态,且取精度较高的混沌系统临界阈值时,输入一定功率的白噪声也会引起系统状态的改变,即系统产生虚警。虚警率随着噪声功率的降低而增加,当噪声功率下降到一定值后,虚警率又开始下降,即虚警率存在峰值点。且虚警率与混沌临界阈值的精度有关,临界阈值精度越高,其对应的虚警率越高。

Chaotic system has the characteristics that immune to noise and it is sensitive to the signal whose frequency is same as the inner signal＇s frequency in a chaotic system in theory.Hereby weak signal hides in strong broad band background noise can be detected by chaotic system.But in the actual simulating process,it finds when choosing critical value of chaotic system with higher precision,pure noise inputs into chaotic system which is under critical state will probably induce to system state variation,namely producing false alarm.The false alarm rate is increasing along with the decreasing of noise power,while the false alarm rate is beginning to decrease when noise power descend to certain value,namely the false alarm rate exists peak value.And the false alarm rate is related to precision of the critical value of chaotic system.The higher precision of the critical value of chaotic system is,the higher the false alarm rate of the chaotic system is.