Research And Development Of Distributed Optical Fiber Temperature Measurement System

In recent years, distributed fiber optic temperature measurement system gradually become a hot topic with a good performance in the field of temperature measurement as to the rapid development of optical fiber and weak signal detection technology. Distributed optical fiber temperature measurement system increasingly popular as a fire distributed alarm system in recent years. In a distributed fiber optic temperature measurement systems, optical fiber as the transmission medium for transmitting optical signals, but also as a parameter sensing medium detecting the parametric variation of the optical signal. Distributed optical fiber temperature measurement system can achieve a continuous distributed temperature measurement, and have the advantages of anti-electromagnetic interference and explosive and other harsh environments, has been widely used in the field of high-voltage cable, oil wells, dams, road tunnels etc.Some theoretical analysis and experimental research has been made for distributed optical fiber Raman temperature measurement in this thesis. Completed the design and implementation of the system according to Raman backscattering theory. According to the signals characteristics of distributed optical fiber temperature sensing system, using the cumulative averaging algorithm and wavelet algorithm to processing and analysis the mixed Gaussian white noise, and collected data for calibrate experiment. The main contents of the thesis are as follows:1. On the basis of the principle and demodulation method of distributed optical fiber temperature measurement, to determine the overall structure of the program of distributed optical fiber temperature measurement system, Distributed a real-time calibration system approach of optical fiber temperature measurement system based on the overall structure of the program. According to the overall structure of the program to selected and analyzed system module. Depending on the system needs to designed and analyzed system of control module.2. Analyzed the characteristic of Raman temperature sensor signal, and on this basis, focuses on methods to improving the SNR of the system signal, including the cumulative averaging recursive algorithm denoising and wavelet denoising. Data processing was introduced in detail and analysis of the effects of various algorithms to improve signal to noise ratio.3. Experimental system built for temperature calibration experiments. Sump modules and noise removal algorithm previously proposed has been analyzed to the improvement of the performance of the system. Use cubic spline interpolation to error correction of temperature curve.