Research On Vehicle Vibration Signal Recognition Method Based On φ-OTDR System

The intelligent transportation sensing system is based on modern technologies such as integrated information,communication,and sensing technologies.The support of traffic information is essential for realizing an intelligent transportation system.Therefore,this paper proposes a phase-sensitive optical time domain reflectometer(φ-OTDR)system based on distributed fiber optic sensing technology with wide sensing bandwidth and high sensitivity,which detects vibration signals generated by vehicles traveling on the road and effectively reduces blind spots in vehicle detection.This paper focuses on optimizing the signal processing method in the φ-OTDR system to improve the system’s detection capability for vehicle vibration signals.The specific research contents are as follows:1.The composition and working principle of the distributed fiber optic disturbance sensing system were studied.The relationship between amplitude and external disturbance and the vehicle vibration detection principle of the φ-OTDR system were analyzed.A distributed fiber optic sensing vehicle vibration system based on φ-OTDR was designed and constructed.The system’s overall structure,the critical components used,and the detection method adopted were determined through analysis and research.The framework structure of the system was optimized and integrated.2.The external environment may interfere with the sensing system,and the background noise near the vibration position is relatively large.Guided edge filtering(GEF)and edge variation mode decomposition(E-VMD)detection algorithms were proposed to filter and process the collected fiber optic data,which effectively improved the signal-to-noise ratio of the fiber optic sensing vibration signal.Piezoelectric ceramics and speakers were used to simulate vehicle vibration experiments.Two algorithms were used to denoise the time-space two-dimensional fiber optic signal matrix under speaker noise interference.The experimental results showed that compared with the traditional amplitude differential detection algorithm,the maximum signal-to-noise ratio of the vibration signal processed by the new algorithm increased by 5.1 times,which can more accurately detect the vibration signal.3.The application of the φ-OTDR system for vehicle vibration signal detection was studied.The vibration signals of vehicles traveling on the highway were collected in the experiment,and the GEF detection algorithm,E-VMD detection algorithm,and traditional amplitude differential detection algorithm proposed in this paper were compared.The results showed that compared with the conventional amplitude differential detection algorithm,the two signal detection methods presented in this paper could improve the signal-to-noise ratio of vehicle vibration signals by up to 3.5 times.