基于SFED和RBS响应区间边界的φ-OTDR振动定位研究

Vibration Location ofφ-OTDR Based on SFED and RBS Response Section Boundary

针对传统管道泄漏监测系统的空间分辨率易受探测脉冲宽度限制的问题,提出一种用瑞利后向散射(Rayleigh back scattered, RBS)响应区间边界结合空-频能量分布定位分布式光纤振动入侵事件的方法。利用空间频率能量分布显示RBS响应区间的左边界来表征振动入侵事件的准确位置。采用不同宽度的探测脉冲对设计的相敏光学时域反射仪(φ-optical time-domain reflectometer,φ-OTDR)系统进行振动检测实验,研究了RBS响应区间随探测脉冲宽度变化的特性。然后通过3种不同环境下的振动测试,验证了采用空-频能量和RBS响应区间边界相结合的方法进行振动定位的可行性和优越性,实验证明采用提出的方法,在采样率为50 MS/s时,系统定位精度为2 m。

This paper proposes a method for locating distributed fiber vibration intrusion events using Rayleigh backscattering(RBS)response section boundary combined with air-frequency energy distribution,aiming to address the issue of limited spatial resolution in traditional pipeline leakage monitoring systems due to the width of the detection pulse.The spatial frequency energy distribution is used to display the left boundary of the RBS response section to characterize the exact location of vibration intrusion events.Vibration detection experiments were carried out on the designed phase-sensitive optical time-domain reflectometer(φ-OTDR)with different width detection pulses,and the characteristics of RBS response section varying with the width of detection pulses were studied.Then,through vibration tests in three different environments,the feasibility and superiority of vibration location by combining air-frequency energy and RBS response section boundary are verified.The experiments show that the location accuracy of the system is 2mwhen the sampling rate is 50MS/s.