基于BOTDA技术的分布式光纤传感系统的研究

发布时间：2018-06-24 05:03

本文选题：分布式 + BOTDA　；参考：《吉林大学》2017年硕士论文

【摘要】：20世纪70年代以来,伴随着光纤通信技术的超快速发展而融合衍生出来的分布式光纤传感技术逐渐走进了国计民生的方方面面,在结构安全康健监测领域有着重要的实用地位。它不仅具有传统光纤传感器所具备的体积小、质量轻、抗电磁、抗辐射、抗腐蚀等优点,还将信息传输与传感合二为一,大大减小了传感器的工艺耗能成本,在很多人工难以完成的检测工作中,它都显示出了超强的应用能力,因此逐渐受到了广大科研工作者的青睐。传统的基于受激布里渊散射光时域分析(Brillouin optical time domain analysis,BOTDA)技术的分布式光纤传感系统不仅需要大量的测量时间,还存在很大的噪声干扰,使得测量结果误差很大,严重影响传感测量的时效性。本研究中,我们针对测量时间较长和噪声较大的问题,提出了采用累加平均和小波变换相结合的灵活的信号处理方法,将labVIEW和MATLAB相结合实现此种手段,大大减小了系统测量时间,系统的信噪比得到了较大幅度的提升。文章首先对基于BOTDA技术的分布式光纤传感课题做了基本介绍,对基于三种散射效应的光纤传感技术理论进行了较为详细的阐述。接着,针对本文要研究的BOTDA光纤传感系统,从受激布里渊散射的理论、传感机理、阈值以及温度和应变与布里渊频移的关系等多个方面做了较为详细的研究,对即将使用的光电器件、数据采集卡性能参数等进行了较为详细的介绍,并据此设计出了本实验的BOTDA传感测量系统方案。根据BOTDA系统基本结构,介绍并分析了影响该系统性能的主要参数指标,包括测量精度、空间分辨率、传感距离、测量时间等。最后,详细介绍了用于激发受激布里渊散射效应的调制脉冲的制作过程,给出了部分FPGA程序示例,同时利用labVIEW和MATLAB相结合的技术,设计出以labVIEW为平台的累加平均和小波变换的数据处理模块,实现了集扫频、采集、信号处理于一体的BOTDA测量控制系统。为验证系统的有效性和数据处理方式的时效性,本文分别进行了基于该实验系统的温度测量实验和分布式测量实验,取得了较好的实验效果,为接下来的系统优化奠定了坚实的基础。
[Abstract]:Since 1970s, with the rapid development of optical fiber communication technology, the distributed optical fiber sensing technology has gradually entered into all aspects of the national economy and people's livelihood, and has an important practical position in the field of structural safety and health monitoring. It not only has the advantages of small volume, light weight, anti-electromagnetic, anti-radiation, anti-corrosion and so on, but also combines the information transmission with the sensor, which greatly reduces the process energy cost of the sensor. In a lot of manual difficult detection work, it has shown the super ability of application, so it has been gradually favored by the majority of scientific research workers. The traditional distributed optical fiber sensing system based on stimulated Brillouin scattering optical time domain analysis (Brillouin optical time domain analysis) not only requires a lot of measurement time, but also has a lot of noise interference. The timeliness of sensing measurement is seriously affected. In this study, aiming at the problem of longer measurement time and larger noise, we put forward a flexible signal processing method which combines cumulative average and wavelet transform, and realizes this method by combining LabVIEW and MATLAB. The measurement time is greatly reduced and the signal-to-noise ratio of the system is greatly improved. In this paper, the distributed optical fiber sensing based on BOTDA technology is introduced, and the theory of optical fiber sensing based on three scattering effects is described in detail. Then, the theory of stimulated Brillouin scattering, sensing mechanism, threshold value and the relationship between temperature and strain and Brillouin frequency shift are studied in detail for BOTDA optical fiber sensing system. In this paper, the photoelectric devices and data acquisition card are introduced in detail, and the BOTDA sensing system is designed. According to the basic structure of BOTDA system, the main parameters affecting the performance of BOTDA system are introduced and analyzed, including measurement precision, spatial resolution, sensing distance, measurement time and so on. Finally, the fabrication process of modulation pulse which is used to excite stimulated Brillouin scattering effect is introduced in detail, and some examples of FPGA program are given. At the same time, the technology of combining LabVIEW and MATLAB is used. The data processing module of accumulative average and wavelet transform based on LabVIEW is designed, and the BOTDA measurement and control system is realized, which integrates sweep frequency, acquisition and signal processing. In order to verify the effectiveness of the system and the timeliness of the data processing, the experiments of temperature measurement and distributed measurement based on the experimental system are carried out in this paper, and good experimental results are obtained. It lays a solid foundation for the following system optimization.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP212

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