Distributed Optical Fiber Perimeter Security Technology Based on Φ-OTDR with Interference Fading Suppression
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摘要:
基于相位敏感光时域反射计（Φ-OTDR）的分布式光纤振动传感系统在铁路周界安防中有着重要的应用前景. 为降低Φ-OTDR中固有的相干衰落对相位解调的影响，提高扰动信号识别率，提出一种基于矢量旋转滑动平均（MVRA）的相干衰落抑制方法. 首先，对探测信号复矢量化，并对各位置的复矢量信号按初相角进行旋转对齐；然后，采用滑动平均的方法缓和信号幅度起伏以及减小噪声功率，提高信噪比，进而抑制相干衰落；其次，从衰落抑制信号解调出扰动信号，将MVRA与频谱提取重组（SERM）、数字向移变换（DPST）方法进行对比，通过差分相位标准差验证抗衰落效果；最后，通过搭建分布式光纤周界入侵检测实验平台，模拟环境噪声、应力破坏、攀爬、剪网4种防护扰动信号，以解调的相位灰度图作为特征图像，使用卷积神经网络进行模式识别. 实验结果表明：相比SERM、DPST，MVRA能更高效地抑制衰落，当滑动窗长50 ns时，MVRA提高11.2 dB信噪比；扰动信号的识别率由衰落抑制前的88%提高到衰落抑制后的92%.
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关键词:
- 相位敏感光时域反射计 /
- 相干衰落 /
- 周界安防
Abstract:Distributed optical fiber vibration sensor based on phase-sensitive optical time-domain reflectometry (Φ-OTDR) has important application prospects in railway perimeter security. In order to reduce the influence of inherent interference fading in Φ-OTDR on phase demodulation and improve the recognition rate of disturbance signals, an interference fading suppression method based on moving vector rotating average (MVRA) was proposed. Firstly, the detected signal was characterized by a complex vector, and the complex vector signals at each position were rotated and aligned according to their initial phase angles. Then, the moving average method was used to improve the signal-to-noise ratio by mitigating the fluctuation of the signal amplitude and reducing the power of the detected noise, thereby suppressing interference fading. Next, the disturbance signal was demodulated from the suppressed fading signal. MVRA was compared with spectrum extraction and remix (SERM) and digital phase-shift transform (DPST) methods, and the anti-fading effect was verified by the standard deviation of the differential phase. Finally, an experimental platform for distributed optical fiber perimeter intrusion detection was built to simulate four kinds of protective disturbance signals, including environmental noise, stress damage, climbing, and net shearing. The demodulated phase grayscale image was taken as the feature image, and then a convolutional neural network was used for pattern recognition. The experimental results show that MVRA can suppress fading more efficiently than SERM and DPST. When the sliding window length is 50 ns, the signal-to-noise ratio is improved by 11.2 dB, and the recognition rate of disturbance signals is increased from 88% before fading suppression to 92% after fading suppression.
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图 2 外差相干探测 Ф-OTDR实验装置
Figure 2. Experimental setup based on Ф-OTDR for heterodyne interference detection
图 3 原始探测信号解调的幅度和差分相位
Figure 3. Demodulated amplitude and differential phase of original detected signal
图 4 衰落抑制后信号的解调的幅度和差分相位
Figure 4. Demodulated amplitude and differential phase of signal after fading suppression
图 7 功率谱密度在频率10 kHz处沿距离轴的分布
Figure 7. Distribution of power spectral density along distance axis at frequency of 10 kHz
图 8 SERM、DPST和MVRA衰落抑制后解调的差分相位标准差
Figure 8. Standard deviation of demodulated differential phase after fading suppression by SERM, DPST, and MVRA
图 9 周界入侵监测实验平台及防护网
Figure 9. Perimeter intrusion monitoring experimental platform and protective net
图 10 衰落抑制前后4种模拟扰动的模式识别结果
Figure 10. Pattern recognition results of four simulated disturbances before and after fading suppression
表 1 相干衰落抑制前后4种振动模式下解调的差分相位
Table 1. Demodulated differential phase under four vibration modes before and after interference fading suppression
模式 890 m 处解调的相位信号 原始信号解调的相位
分布局部截图衰落抑制后解调的相位
分布局部截图风吹信号 
晃动信号 
敲击信号 
剪切信号 
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[1] 王羽莹. 高速铁路沿线周界入侵报警系统关键技术研究[J]. 铁道通信信号,2017,53(10): 68-72.WANG Yuying. Study of key technology of perimeter intrusion alarm system along high-speed railway[J]. Railway Signalling & Communication, 2017, 53(10): 68-72. [2] 葛妍. 户外周界防护系统综述[J]. 中国安防产品信息,2004(5): 49-54. [3] 曲俊蓉,丁宁. 基于Φ-OTDR的铁轨异物入侵监测方法[J]. 工业控制计算机,2017,30(6): 95-96,99.QU Junrong, DING Ning. A method to monitor railway tracks’ foreign body invasion based on Φ-OTDR[J]. Industrial Control Computer, 2017, 30(6): 95-96,99. [4] 彭龙,邹琪琳,张敏,等. 光纤周界探测技术原理及研究现状[J]. 激光杂志,2007,28(4): 1-3. doi: 10.3969/j.issn.0253-2743.2007.04.001PENG Long, ZOU Qilin, ZHANG Min, et al. Developments in and applications of fiber perimeter detection sensors[J]. Laser Journal, 2007, 28(4): 1-3. doi: 10.3969/j.issn.0253-2743.2007.04.001 [5] 李赛飞,闫连山,李洪赭,等. 铁路通信网络安全的分析测试与可信防御研究[J]. 西南交通大学学报,2018,53(6): 1130-1136,1149.LI Saifei, YAN Lianshan, LI Hongzhe, et al. Analysis and testing of network security for China railway communication networks and proposed architecture based on trusted computing[J]. Journal of Southwest Jiaotong University, 2018, 53(6): 1130-1136,1149. [6] 叶青,潘政清,王照勇,等. 相位敏感光时域反射仪研究和应用进展[J]. 中国激光,2017,44(6): 7-20.YE Qing, PAN Zhengqing, WANG Zhaoyong, et al. Progress of research and applications of phase-sensitive optical time domain reflectometry[J]. Chinese Journal of Lasers, 2017, 44(6): 7-20. [7] 梁可桢,潘政清,周俊,等. 一种基于相位敏感光时域反射计的多参量振动传感器[J]. 中国激光,2012,39(8): 125-129.LIANG Kezhen, PAN Zhengqing, ZHOU Jun, et al. Multi-parameter vibration detection system based on phase sensitive optical time domain reflectometer[J]. Chinese Journal of Lasers, 2012, 39(8): 125-129. [8] DONG Y K, CHEN X, LIU E H, et al. Quantitative measurement of dynamic nanostrain based on a phase-sensitive optical time domain reflectometer[J]. Applied Optics, 2016, 55(28): 7810-7815. doi: 10.1364/AO.55.007810 [9] QIAN H, LUO B, HE H J, et al. Fading-free Φ-OTDR with multi-frequency decomposition[J]. IEEE Sensors Journal, 2022, 22(3): 2160-2166. doi: 10.1109/JSEN.2021.3128604 [10] 周俊,潘政清,叶青,等. 基于多频率综合鉴别Φ-OTDR系统中干涉衰落假信号的相位解调技术[J]. 中国激光,2013,40(9): 119-124.ZHOU Jun, PAN Zhengqing, YE Qing, et al. Phase demodulation technology using a multi-frequency source for discrimination of interference-fading induced false alarms in a Φ-OTDR system[J]. Chinese Journal of Lasers, 2013, 40(9): 119-124. [11] GU J F, LU B, YANG J Q, et al. High SNR Φ-OTDR based on frequency and wavelength diversity with differential vector aggregation method[J]. IEEE Photonics Journal, 2020, 12(6): 1-12. [12] WU Y, WANG Z N, XIONG J, et al. Interference fading elimination with single rectangular pulse in Φ-OTDR[J]. Journal of Lightwave Technology, 2019, 37(13): 3381-3387. doi: 10.1109/JLT.2019.2916682 [13] HE H J, YAN L S, QIAN H, et al. Suppression of the interference fading in phase-sensitive OTDR with phase-shift transform[J]. Journal of Lightwave Technology, 2021, 39(1): 295-302. doi: 10.1109/JLT.2020.3023699 [14] 杨经国. Φ-OTDR分布式光纤传感系统信噪比增强与模式识别研究[D]. 成都: 西南交通大学, 2018. -
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