为了实现在大范围被测区域内实时温度监测的功能,选用光纤布拉格光栅(FBG)测温网络,同时,为了提高系统的温度测试精度和抗干扰能力,设计了基于差分校正的FBG测温网络系统。系统在原有测试结构的基础上,增加了校正光纤探头,从而针对任意位置上个别环境变化造成的温度误差进行校正。通过理论推导,差分校正值表达式被给出,并由此设计了差分校正算法。实验采用温度控制箱使被测区域温度从20℃变化为80℃,最小温度改变量为1.0℃。实验结果显示:回波中心波长产生的偏移量和温度之间大致每1.0℃的温度变化产生35-45 pm的偏移。差分校正型测温系统的温度检测误差为0.47%,优于传统的测温系统,并且基于差分校正的测温系统受局部环境影响很小,具有较高的系统稳定性。
In order to achieve real-time temperature monitoring function in a wide range measured area,fiber Bragg grating( FBG) temperature measurement network is selected. Meanwhile,in order to improve precision of temperature measurement and anti-jamming capability,FBG temperature measurement network system based on differential correction is designed. Based on original structure of the test system,correction fiber-optic probe is added,so that the temperature error from individual environmental change can be corrected for any position.Through theoretical analysis,the expression of difference correction values is given,and the differential correction algorithm is designed. Temperature control box is used in experiments,so that the temperature of measured region can be changed from 20- 80 ℃,and its the minimum value of temperature change is 1. 0 ℃. Experimental results show that approximately every 1. 0 ℃ temperature change generate 35 - 45 pm offset between offset values generated by echo center wavelengths and temperature. In the differential correction type temperature measurement system,temperature measurement error is 0. 47 %,prior to traditional measurement system. It is little affected by the local environment in the differential correction type temperature measurement system,so it has high system stability.