光纤矢量水听器系统本底噪声的自适应抵消

Adaptive Cancellation of Background Noise of Fiber Optic Vector Sensor System

本底噪声是制约干涉型光纤矢量水听器系统在低频远距离目标探测领域中应用的重要因素之一。为降低系统的本底噪声,提出了一种基于自适应噪声抵消的降噪方法。在光学系统中增加一个与传感迈克耳孙干涉仪结构参数相等的对声压不敏感的参考干涉仪作为参考通道,以获得由光源与电路等共同噪声源引入到各干涉仪的高相关噪声。然后,使用归一化均方根误差的自适应算法分别对声压及加速度信号中与参考信号高相关的噪声部分进行抵消。湖试数据的分析结果表明,该方案能够有效降低系统本底噪声,其中对电磁干扰带来的50 Hz倍频信号的抑制能力高达15~25 dB,对500 Hz以上的平坦噪声谱的抑制为3 dB左右。

Background noise is one of the most important properties for the interferometric fiber optic vector sensor systems,which limits the systems＇ application of the detection of the long distance and low frequency targets.To reduce the background noise,a noise suppression scheme based on an adaptive noise canceller is proposed.A pressure insensitive reference fiber optic Michelson interferometer is added as a reference sensor,whose structural parameters are the same as those of the sensing fiber optic interferometers.Then the background noises of the pressure or acceleration signal,which are highly correlated with the reference signal,can be cancelled by the normalized least root mean square error algorithm.The results of a lake trial show that the scheme can effectively reduce both the background noise of the pressure and the accelerometer channels,which can suppress the 50 Hz multiples of the electromagnetic interference by 15～25 dB,and the flat phase noise above 500 Hz by about 3 dB.