| 摘要 |
Monitoring the position of a structure using an optical fibre distributed acoustic sensor (DAS) deployed in a relationship with respect to the structure comprises using the distributed acoustic sensor, 462, to detect acoustic signals, emitted by a plurality of sources, 48, at a plurality of acoustic sensor positions along the fibre, 32. The relative positions of the sensors are calculated and from this the shape, or shape and position, of the structure can be determined. In another embodiment detecting vibration in a structure using an optical fibre DAS deployed in a known relationship with respect to the structure comprises detecting backscattered light on the fibre and from this processing a signal to determine a frequency of oscillation of the vibrations in the structure. The signal detected may be frequency filtered into low frequencies, (<100Hz) used for vibration detection, and high frequencies (>1kHz) for position monitoring. |
