一种提高分布式光纤测温系统空间分辨率的线性修正算法

由于分布式光纤喇曼测温系统带宽不足,导致系统的空间分辨率低;当光纤的感温区域长度接近空间分辨率的时候,系统温度响应幅值不够,导致测温不准.为解决此问题,本文提出了一种线性修正算法;在分析温度与喇曼比值关系及系统的频率响应特性的基础上,建立了该算法的数学模型,搭建了基于单模光纤的10 km分布式测温系统,并利用该算法进行了相关测温实验.实验结果与理论分析一致,该算法能有效修正3~6 m光纤的温度响应幅值,使系统测温准确度达1℃,测量时间为40 s.本算法在不增加效系统成本的同时,克服了系统带宽不足,优化了空间分辨率、温度分辨率及测量时间.

A Linear Correcting Algorithm for Improving Space Resolution of Distributed Optical Fiber Raman Temperature Measurement System

Because of deficient bandwidth, the space resolution of Distributed Optical Fiber Raman Temperature Sensor (DOFRTS) is low. When the sensing length of fiber is close to space resolution, there is no accurate temperature response. For solving the problems, a new linear algorithm is proposed. Firstly, the relationship between Raman ratio and temperature and the characteristics of frequency response are analyzed, and then a mathematical model is built up for this algorithm. A single-mode temperature sensor system for 10 km long is built up, some related experiments are carried out by using the algorithm. Experiment results are consistent with theoretical analysis, the temperature amplitudes of testing fiber from 3 meters to 6 meters are corrected. The temperature measurement accuracy reaches 1℃ and measuring time is 40 seconds. By applying this algorithm, the limit of bandwidth can be overcome effectively and the system cost is cut down obviously, at the same time, space resolution, temperature resolution and measuring time are optimized.