Research On High Accuracy Extraction Of Botdr Distributed Sensor Signal

The distributed measurement techniques which based on Brillouin optical time domain reflection is a kind of spontaneous Brillouin scattering. It can measure the external physical parameter along the fiber path distribution of the whole fiber length continuously. And it can provide means of simultaneous access to the measured physical quantity with time and spatial distribution of the state change. Based on the extensive investigation, the mechanism of BOTDR distributed optical fiber sensing is researched, the problems of sensing accuracy about the Brillouin scattering distributed optical fiber sensing system is analyzed and the precision of the measuring system are studied and improved. The main contents are as follows:Firstly, the classification of distributed optical fiber sensing technology is introduced briefly, and the technology development situation is discussed. The optical power, temperature, and strain relationship between Brillouin frequency shift s is researched. Besides, the problem of measurement accuracy of the BOTDR system is discussed, and several detection methods of Brillouin optical time domain reflection technology are briefly introduced. The advantages and disadvantages of different detection methods are analyzed and the working principle of the system is described. At last, the final performance issues for BOTDR system are thoroughly analyed and discussed.Secondly, in view of the high accuracy need of Brillouin scattering spectrum center frequency extraction, a new Brillouin scattering spectral fitting algorithm FEA-Newton is proposed, it can extract the Brillouin scattering frequency with high precision, in order to improve the measuring precision further, the CS-IDE algorithm is proposed. The simulation results show that both the CS-IDE and FEA-Newton can effectively improve the accuracy of the measurement system, and the CS-IDE algorithm is better than the FEA-Newton algorithm in measurement accuracyFinally, based on the Brillouin optical time domain reflection distributed optical fiber sensing system, the distributed temperature measurement is carried out;According to the requirement of measurement system, the experimental equipment is selected carefully, and the parameters and functions are briefly introduced, then make the distributed temperature curves of experimental simulation, and prove the practicability and feasibility of fitting algorithm.