分布式光纤振动传感系统的多级零频点定位研究

摘要

为了减少直线结构Sagnac分布式光纤传感系统的定位误差,提出一种多级零频点的优化方法,通过分析直线结构Sagnac分布式光纤传感定位原理,确定固定的采样速率下离散化是造成定位误差大的原因.并分析得出振动信号频域曲线会周期出现多个零频点,进而对振动定位的多级零频点优化方法进行了理论推导,阐明高倍零频点下的定位误差会有效减小.通过实验验证表明,在总长为11.769 km的传感光纤上,优化后的定位方法在不改变采样速率下可保证定位误差提升到±20 m范围内,可以基本满足系统对外界振动信号进行精确定位的要求.%A novel optimization method of multiple null frequency is proposed,in order to reduce the locating error of linear Sagnac distributed optical fiber vibration sensing system. The traditional locating method is firstly intro-duced. By analyzing the phenomenon of multiple null frequency,the reasons for the increase of positioning error are explained. The optimization method of multiple null frequency is theoretically presented and experimentally verified. The experiment result shows that the locating error is within the range of ±20 m over a total fiber length of 11.769 km,which can meet the need of accurate vibration location.