针对长输管道的实时监测和周界的安全预警,建立基于双Sagnac干涉仪的分布式光纤传感安全预警系统,包括双Sagnac干涉仪的光路系统和基于LabVIEW平台的控制与检测软件。分析了管道破坏和周界入侵等产生的外界扰动信号对光相位信号的调制原理和利用频域幅值法的定位原理,并研究了脉冲扰动信号和连续扰动信号的过零数分布情况。基于以上原理,开发了报警算法、定位算法和外界扰动类型判别算法软件,并进行了实验研究。实验结果表明,该安全预警系统可实现外扰动的实时监测、定位和扰动类型判别功能,具有定位精度较高、运行稳定可靠、操作便捷等优点,在工程中具有良好的应用前景。 Aiming at the real-time monitoring of long-distance pipeline and the perimeter safety pre-warning, a distributed pre-warning system based on double Sagnac interferometer is established. The optical system includes dual Sagnac interferometer and control and inspection software based on LabVIEW. The principle of modulating the optical phase signal by external disturbance signals such as pipeline destruction and perimeter intrusion, and the localization principle by using the frequency domain amplitude method are analyzed. The distribution of zero-crossing number of pulse disturbance signal and continuous disturbance signal are also studied. Based on the above principles, the alarm algorithm, the positioning algorithm and the algorithm of discriminating type of external disturbances are developed, and the experimental research is carried out. The experimental results show that the safety early warning system can realize the real-time monitoring, positioning and disturbance type discrimination of external disturbance. It has the advantages of high positioning accuracy, stable and reliable operation, convenient operation and so on. It has good application prospect in engineering.