为解决分布式光纤振动传感系统的定位准确性弱、灵敏度低及响应速率慢等问题，提出了一种基于相位敏感光时域反射的动态方差阈值算法。该算法将经过带通滤波预处理后的信号进行方差处理、高斯模糊、阈值寻峰以及重心精确，解决了长距离DVS检测由于背向瑞利散射信号的衰减以及运算量大造成的响应时间长的问题。并且采用并行编程技术将运算速度提高了184%，从而快速准确地确定扰动发生位置。实验研究了39 km长度的光纤上人为扰动和噪声的区别，并通过动态方差阈值算法消除了噪声的影响并确定了扰动位置。该系统响应时间为1 s，空间分辨率为20 m，定位误差低于0.1%。

Therefore, aiming at the problem of long-distance complex noise interference and signal attenuation, combined with the characteristics that variance analysis can detect the vibration quickly and effectively in one-dimensional signal, this paper proposes a dynamic variance threshold algorithm, and uses the parallel programming technology to improve the response speed of the system. The signal preprocessed by the band-pass filter is processed by variance processing, Gaussian blur, threshold peak seeking, and accurate center of gravity. The problem of long response time caused by the attenuation of Rayleigh scattering signal and the large amount of computation in the long-distance DVS detection is solved. The parallel programming technology is used to improve the operation speed by 184%, so as to quickly and accurately determine the location of the disturbance.The difference between the man-made disturbance and the noise on a 39 km long optical fiber is experimentally studied, and the influence of the noise is eliminated by the dynamic variance algorithm.The response time of the system is 1 second, the spatial resolution is 20 meters, and the positioning error is less than 0.1%.In order to solve the problems of weak positioning accuracy, low sensitivity, and slow response speed of the distributed fiber vibration sensor system, a dynamic variance threshold algorithm based on the phase-sensitive photosensitive time domain reflection is proposed. The signal preprocessed by the band-pass filter is processed by variance processing, Gaussian blur, threshold peak seeking, and accurate center of gravity. The problem of long response time caused by the attenuation of Rayleigh scattering signal and the large amount of computation in the long-distance DVS detection is solved. The parallel programming technology is used to improve the operation speed by 184%, so as to quickly and accurately determine the location of the disturbance. The difference between the man-made disturbance and the noise on a 39 km long optical fiber is experimentally studied, and the influence of the noise is eliminated by the dynamic variance algorithm. The response time of the system is 1 second, the spatial resolution is 20 meters, and the positioning error is less than 0.1%.