Adaptive time delay estimation of distributed fiber optic perturbation sensor

Considering the defects of shorter monitoring distance, the sensitiveness to electromagnetic interference and higher cost of maintenance in traditional security guard system, a novel distributed fiber optic perturbation sensor was proposed. Composed of the dual M-Z (Mach-Zehnder) interferometers of all fiber instruments, the sensor proposed can locate the position of the intruder and send out the alarm by the sensitiveness to perturbation of fibers. The experiments show that the signal of intruder's perturbation is band-limited. According to the perturbation signal characteristics of the sensor, the self adaptive time delay estimation using the LMS (least mean square) algorithm was studied, and the performance of the self adaptive algorithm was provided. The experiment results show that the self adaptive algorithm can be applicable for locating on real time with the locating error less than 200 meters. The sensor designed has been successfully applied in security guard system in several areas.