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提出了一种基于双光束干涉的分布式光纤振动传感器,利用双路瑞利散射信号的干涉效应探测振动信号并利用传统的光时域反射计定位原理进行定位。基于该原理提出一种新的信号处理方案,在传统移动平均算法的基础上引入间隔参数并对信号进行标准化处理,不仅可以降低系统运算量,而且能去除因干涉灵敏度升高造成的本底噪声影响,提高振动信号的信噪比。实验结果表明,该系统可以有效探测到外界扰动信号并进行精确定位,而且探测灵敏度较高。当传感光纤长度为5km时,系统空间分辨率可以达到20m,信噪比约为8.5dB。该系统可以用于管道安全预警和周界安防以及结构健康监测等领域。
A distributed optical fiber vibration sensor based on double beam interference is proposed to detect the vibration signal by using the interference effect of the dual Rayleigh scattering signal and to locate it by using the traditional optical time domain reflectometer positioning principle. Based on this principle, a new signal processing scheme is proposed. Based on the traditional moving average algorithm, the interval parameter is introduced and the signal is normalized. This not only reduces the computational complexity of the system, but also removes the noise floor caused by the increase of the interference sensitivity Influence, improve the signal-to-noise ratio of the vibration signal. The experimental results show that the system can effectively detect the external disturbance signals and locate them accurately, and the detection sensitivity is high. When the sensing fiber length of 5km, the system spatial resolution can reach 20m, signal to noise ratio of about 8.5dB. The system can be used for early warning of pipeline safety and perimeter security and structural health monitoring and other fields.