基于拉曼散射的分布式光纤温度传感器研究

发布时间：2018-10-17 11:35

【摘要】：分布式光纤温度传感技术是利用后向反射的拉曼散射光对光纤所在的温度场进行测量的技术,分布式光纤温度传感具有体积小、抗干扰、精度好等特点,广泛应用于医疗、工业、国防等诸多领域。本文对分布式光纤温度传感器进行了整体设计和系统研制,主要研究工作内容如下:(1)对拉曼散射中的单通道解调算法和双通道解调算法进行了深入的比较研究,分析了这两种算法的各自优缺点。进一步采用双通道解调算法进行了系统设计,并开展了相关数据的采样实验。(2)开展了分布式光纤温度传感器中的处理器、AD等关键器件的设计选型研究。设计的分布式光纤温度传感系统的处理器采用了FPGA+DSP+ARM的模式,一方面,传统的PC+FPGA的模式具有模块简单、开发容易的特点,但是也使得整个系统的功耗和体积变得比较大;另一方面,FPGA+DSP+ARM的模式能够充分利用各个处理器的优势:FPGA具有硬件可编程的特性,适合做高速逻辑运算,DSP适合数学运算,而ARM适合做接口设计,这样整个系统达到了耗能低、速度快、体积小的特点。另外,AD元件采用了单通道分时复用的工作方式,降低了整个系统的设计成本。(3)完成分布式光纤温度传感器系统中一种新型高速PCB的设计。具体工作包括:模拟电路的设计、AD电路的设计、PCB的整体布局等。设计工作中充分考虑了采样过程中的模拟信号、高速信号等关键信号的完整性,为后续拉曼信号的采集提供了很好的保障。(4)开展了分布式光纤温度传感器的软件设计研究。一方面,在FPGA平台上,使用Verilog设计了一种高速累加器,提高了拉曼信号的信噪比;另一方面,在DSP平台上,完成了Sys/bios下温度解调算法的实现及DSP与FPGA的同步控制;另外,在ARM平台上,充分利用嵌入式领域相关成熟的技术,开展了SQL数据库的设计、QT下人机交互界面的设计和基于Syslink双核通信的设计。
[Abstract]:Distributed optical fiber temperature sensing technology is used to measure the temperature field of optical fiber by backward reflected Raman scattering light. Distributed optical fiber temperature sensor is widely used in medical treatment because of its small size, anti-interference, good precision and so on. Industry, national defense and many other fields. In this paper, the distributed optical fiber temperature sensor is designed and developed. The main work is as follows: (1) the single channel demodulation algorithm and the double channel demodulation algorithm in Raman scattering are compared. The advantages and disadvantages of the two algorithms are analyzed. Furthermore, the system is designed by dual-channel demodulation algorithm, and the data sampling experiment is carried out. (2) the design and selection of key devices such as processor, AD and other key devices in distributed optical fiber temperature sensor are studied. The processor of the distributed optical fiber temperature sensing system adopts the FPGA DSP ARM mode. On the one hand, the traditional PC FPGA mode has the characteristics of simple module and easy development, but it also makes the power consumption and volume of the whole system become larger. On the other hand, the mode of, FPGA DSP ARM can make full use of the advantages of each processor: FPGA has the characteristic of hardware programmable, it is suitable for high speed logic operation, DSP is suitable for mathematical operation, and ARM is suitable for interface design, so the whole system achieves low energy consumption. Fast speed, small size characteristics. In addition, single channel time-sharing multiplexing is adopted in AD components, which reduces the design cost of the whole system. (3) A new high speed PCB is designed in distributed optical fiber temperature sensor system. Specific work includes: analog circuit design, AD circuit design, PCB overall layout. In the design work, the integrity of the analog signal and the high speed signal are fully considered, which provides a good guarantee for the subsequent Raman signal acquisition. (4) the software design of the distributed optical fiber temperature sensor is carried out. On the one hand, on the FPGA platform, a high-speed accumulator is designed using Verilog to improve the signal to noise ratio of Raman signal. On the other hand, on the DSP platform, the temperature demodulation algorithm under Sys/bios and the synchronization control between DSP and FPGA are realized. On the platform of ARM, the design of SQL database, human-computer interface under QT and dual-core communication based on Syslink are carried out by making full use of the mature technology in embedded field.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP212

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