Research On The Noise Reduction Technology Of Distributed Acoustic Sensing System Based On The Coherent Optical Time-domain Reflectometry

Optical fiber sensing technology in coherent optical time domain reflection has manyadvantages, such as high sensitivity, immunity to electromagnetic interference, corrosionresistance and so on. It has become the focus of academic attention and research. Thispaper focuses on the denoising technology of distributed acoustic sensing system based oncoherent optical time domain reflectometry technique and analysis wavelet denoising andS coding scheme. The denoising performance is modeled and simulated. The main work ofthis paper includes the following:Firstly, the effect mechanism of acoustic wave and optical fiber is researched. TheRayleigh scattering phenomena and principle is elaborated and the optical time domainreflectometry sensing system based on Rayleigh scattering effect is analyzed.Secondly, because the acoustic signal is highly vulnerable to external noiseinterference, the cumulative number of average and wavelet denoising algorithm wereadopted to filter system noise. The principle of wavelet denoising is analysis. Based onselection of the universal threshold and the improvement of hard and soft thresholdfunction, a new wavelet denoising algorithm is presented. The algorithm denoising effecthas been simulation analysis.Thirdly, in order to further reduce noise in the system, pulse light of detecting systemis code to denoise. The S coding and denoising principle is analysis and the modeling andsimulation is done using MATLAB.At last, this paper designs and builds a distributed acoustic sensing system based oncoherent optical time domain reflectometry technology. It analyses of parameters of thesystem devices and tests performance. Debug the system and get the back scattering curveof Rayleigh. System experiments show that the denoising effect of the new waveletalgorithm is good, which can effectively improve the signal-to-noise ratio of the system.