双马赫-曾德干涉仪型分布式光纤传感系统因灵敏度高而易受环境噪声及系统噪声的影响, 使得利用直接互相关算法计算扰动信号位置存在较大误差.采用二次互相关算法, 先对两路接收信号做互相关运算, 再与其中一路信号的自相关结果做互相关运算, 通过对两路信号的时延估计对扰动信号定位, 减小了噪声带来的误差并提高计算准确度.对该算法进行了理论仿真和分析, 搭建了实验装置进行了实验验证.实验结果表明, 与采用直接互相关定位算法结果比较, 采用本文算法能够有效提高系统对扰动信号的定位准确度, 且具有较高的实时性.

The dual Mach-Zehnder interferometer-type distributed optical fiber sensing system is susceptible to environmental noise and system noise due to its high sensitivity, which makes a large error in calculating the position of the disturbance signal by direct cross correlation algorithm. The quadratic cross correlation algorithm was used to process the two received signals, and then process the autocorrelation of one signal. The disturbance signal was located by estimating the delay of the two signals. With the improved method, it can reduce the error caused by noise and improve the calculation accuracy. The theoretical simulation and analysis of the algorithm were carried out, and the experimental device was experimentally verified. The experimental results show that compared with the results of using the direct correlation algorithm, the proposed algorithm can effectively improve the positioning accuracy of the disturbance signal and has higher real-time performance.