中文摘要：

将相位敏感光时域反射计应用于油气管道安全监测领域.首先通过理论分析其探测原理,推导出干涉光强与光纤折射率的对应关系,从而论证了该方法的可行性;然后提出了一套新的信号处理方案,从空域及时域两方面对信号进行了处理.空域上,在传统移动平均算法的基础上引入间隔参数并提出一种新的差值算法,提高了信号的信噪比并降低了系统运算量;时域上,提取了入侵位置对应的时域信号并通过采用时频分析以及小波滤波的方法直观表现了外界入侵事件的时域特征.现场实验结果表明,该系统能有效探测到外界入侵事件并进行精确定位,差值信号信噪比达到7.8,d B,定位结果标准差在10,m以内.

英文摘要：

The phase-sensitive optical time domain reflectometer（OTDR）is used in oil and gas pipeline safety monitoring. In this paper,the detection principle of the pipeline security pre-warning system based on coherent Rayleigh scattering was firstly analyzed,and the corresponding relationship between the interference light intensity and the optical fiber refractive index is derived,which proved the feasibility of the system. A new signal processing scheme was then proposed,which processed the signal from both space and time domains. In space domain,an interval parameter was introduced into the traditional moving averaging algorithm so as to improve the SNR of the signal and reduce the system computation amount. Besides,the time-domain signal corresponding to the intrusion position was extracted,and the time-domain characteristic of intrusion signals was demonstrated through time-frequency analysis and wavelet filtering method. The field experimental results show that the system can effectively detect and precisely position external vibration events. The SNR of differential signal can be as high as 7.8,d B,and the standard deviation of positioning results is less than 10,m.