Ultra-high resolution strain sensor network assisted with an LS-SVM based hysteresis model

• 作者: Tao Liu Hao Li Tao He Cunzheng Fan Zhijun Yan Deming Liu Qizhen Sun
• 来源期刊: 光电进展（英文版）
• 年，卷（期）: 2021,（5）
• 所属期刊栏目: Original Article
• 页码范围: 1-11
• 页数: 11页
• 语种: 英文
• DOI: 10.29026/oea.2021.200037

摘要

Optical fiber sensor network has attracted considerable research interests for geoscience applications.However,the sensor capacity and ultra-low frequency noise limits the sensing performance for geoscience data acquisition.To achieve a high-resolution and lager sensing capacity,a strain sensor network is proposed based on phase-sensitive op-tical time domain reflectometer(φ-OTDR)technology and special packaged fiber with scatter enhanced points(SEPs)ar-ray.Specifically,an extra identical fiber with SEPs array which is free of strain is used as the reference fiber,for com-pensating the ultra-low frequency noise in the cp-OTDR system induced by laser source frequency shift and environment temperature change.Moreover,a hysteresis operator based least square support vector machine(LS-SVM)model is in-troduced to reduce the compensation residual error generated from the thermal hysteresis nonlinearity between the sensing fiber and reference fiber.In the experiment,the strain sensor network possesses a sensing capacity with 55 sensor elements.The phase bias drift with frequency below 0.1 Hz is effectively compensated by LS-SVM based hyster-esis model,and the signal to noise ratio(SNR)of a strain vibration at 0.01 Hz greatly increases by 24 dB compared to that of the sensing fiber for direct compensation.The proposed strain sensor network proves a high dynamic resolution of 10.5 pε·Hz-1/2 above 10 Hz,and ultra-low frequency sensing resolution of 166 pε at 0.001 Hz.It is the first reported a large sensing capacity strain sensor network with sub-nε sensing resolution in mHz frequency range,to the best of our knowledge.