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|1. (WO2018035833) DISTRIBUTED FIBRE SENSING SYSTEM AND VIBRATION DETECTION AND POSITIONING METHOD THEREFOR|
|Applicants:||SHANGHAI JIAOTONG UNIVERSITY
|Title:||DISTRIBUTED FIBRE SENSING SYSTEM AND VIBRATION DETECTION AND POSITIONING METHOD THEREFOR|
A distributed fibre sensing system and a vibration detection and positioning method therefor. The system comprises: a signal generating module, a light source module, an optical frequency comb generating module, a frequency sweeping string cutting module, an optical circulator, a sensing fibre, a beat frequency module, a photoelectric conversion module and a detection positioning module. The method comprises: a positioning unit in a detection positioning module generating a plurality of digital band-pass filters with different frequency bands without any overlapping, and performing digital filtering on original data segments from a plurality of swept-frequency detection optical pulses to obtain a plurality of reflectivity curves of a sensing fibre; performing fading elimination processing on the reflectivity curves to obtain a plurality of integrated reflectivity curves of non-interference fading and polarization fading; performing phase processing on the integrated reflectivity curves to obtain phase variance curves; and according to variances in the phase variance curves, determining a vibration point, and finally obtaining the position and a vibration waveform of the vibration point. According to the present invention, the positioning precision is high, the vibration frequency response range is large, and a signal-to-noise ratio of a vibration waveform is high.