基于小波变换的光纤周界定位系统

Fiber-optic perimeter location system based on wavelet transformation

为提高基于双Mach-Zehnder干涉仪结构的光纤周界定位系统的定位精度,对信号频率范围及信噪比对系统定位精度的影响进行了理论分析和仿真研究.在此基础上,提出在选用光缆时需要兼顾对外界振动的敏感性和对外场复杂环境的适应性,以确保在长期可靠运行的前提下,扩展采集信号的频率范围;使用小波阈值降噪算法,提取振动信号的有效频率成分,滤除噪声,提高信噪比.最后进行了监测距离31 km的外场实验,验证了所选用光缆的优良性能和小波降噪算法的有效性.

In order to improve the location accuracy of dual Mach-Zehnder interferometic based fiber-op- tic perimeter location system, the influence of signal frequency range and signal noise ratio （SRN） was ana- lyzed and emulated. Basing on these, a fiber cable, which combines the high-sensitivity to vibration and the adaptability to complex environment, was adopted to ensure the reliability and extend the signal frequency range. The wavelet de-noising algorithm was employed to extract the effective frequency component, filter the noise and advance the SNR. Finally, a field test with 31 km monitoring length was carried out to justify the ex- cellent performance of the proposed fiber cable and the effectiveness of the wavelet de-noising algorithm.