ASYMMETRIC DUAL MACH-ZEHNDER INTERFERENCE BASED DISTRIBUTED OPTICAL FIBRE DISTURBANCE POSITIONING SYSTEM AND POSITIONING METHOD THEREFOR

WIPO Patent Application WO/2017/107657

A1

An asymmetric dual Mach-Zehnder interference based distributed optical fibre disturbance positioning system. Unlike traditional dual Mach-Zehnder distributed optical fibre disturbance sensing systems, in the system, two narrow-band light sources (1a, 1b) are used and corresponding dense wavelength division multiplexers (DWDM) (3a, 3b) are added in front of detectors (4a, 4b), so that backscattering noise can be filtered out from the optical fibre, and the problem that due to the influence of backscattering, a signal to noise ratio is excessively low where a sensing distance is relatively long is solved. A positioning method that can be used for the system. In the method, time-frequency distribution of a disturbance frame signal is obtained by utilizing a fast time-frequency analysis method based on a short-term average frequency, and points near the maximum frequency point are taken as a valid signal segment to perform cross-correlation time delay estimation so as to obtain a time delay, and thus obtaining a disturbance position. The method can position an asymmetric disturbance signal in the system, and has higher positioning precision and stability.

LIU KUN (CN)
LIU TIEGEN (CN)
JIANG JUNFENG (CN)
MA CHUNYU (CN)
CHAI TIANJIAO (CN)
HE CHANG (CN)
TIAN MIAO (CN)
LI ZHICHEN (CN)

PCT/CN2016/103521

June 29, 2017

October 27, 2016

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UNIV TIANJIN (CN)

G08B13/186; G01D5/353; G01H9/00

CN105488935A	2016-04-13
CN102291181A	2011-12-21
CN101701844A	2010-05-05
CN101625258A	2010-01-13
US20020181872A1	2002-12-05
CN101465052A	2009-06-24

BEI&OCEAN (CN)

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