| Compared with traditional sensing technology,optical fiber distributed sensing technology integrates transmission and sensing,has the advantages of continuous distributed detection,long distance detection,high sensitivity and has important application prospects in oil and gas pipelines,perimeter security,large-scale engineering,etc.However,with the in-depth study of the optical fiber distributed vibration sensing system,the detection index of the system is gradually improved,resulting in an increasing amount of data to be processed,processing speed and real-time of signal response are limited.Aiming at the issues above,this thesis proposes the design of optical fiber distributed vibration sensing system based on FPGA,which accelerates the processing of data for the system by using the advantages of FPGA parallel computing and high design flexibility,saves the computing and processing resources of the host computer,and realizes the realtime detection of distributed vibration signals.The main research content of this thesis is as follows:1)The principle of optical fiber distributed vibration sensing system and the key performance parameters of the system are theoretically analyzed,and the main components of the system are selected.Finally the optical fiber distributed vibration sensing system is designed and built.2)The signal of the optical fiber distributed vibration sensing system is analyzed and studied,and the FPGA program architecture design process is designed according to the data structure characteristics of the sensing signal,and the architecture of ADC+FPGA+ARM is adopted.ADC to achieve high-speed acquisition of vibration signal,through the FPGA,the acquired data is processed for packet caching,preprocessing,demodulation and other operations,then through the ARM CPU software,TCP/IP protocol is written so that the FPGA can communicate with the host computer in real time.Finally,the optical fiber distributed vibration sensing system can achieve the real-time of signal processing,with the theoretical sensing distance of 40.96 km,sampling interval of 10.2m and frequency response range of 20 ～ 250 Hz.3)Finally,the performance experimental test and analysis of the system are carried out,and the experimental results show that the performance of the optical fiber distributed vibration sensing system designed in this thesis reaches the expected design goal.The research shows that the optical fiber distributed vibration sensing system designed in this thesis can greatly reduce the data processing pressure of the host computer,save hardware computing resources for the subsequent complex signal processing such as artificial intelligence for the host computer,and provide a new solution for the real-time detection of the signal of the long-distance optical fiber distributed vibration sensing system. |
