Seismic activity monitor based on optical fiber Bragg gratings
US7122783B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 2, 2004 |
| Grant date | Oct 17, 2006 |
| Priority date | — |
| Expiry date | Nov 2, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V1/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Fiber Bragg gratings (FBG) seismic activity sensors coupled in sensor arrays provide increased sensitivity to seismic activities, lower strain values and an absence of EMI allowing detection of troop and vehicle movements based on ground vibrations generating seismic signals. The FBG sensor head features a spring-mass configuration with a head surface, fiber optic cable and the FBG sensor attached to a spring that stretches during the acceleration of the mass. Waves propagating inside the earth and along the ground arriving at the sensor locations cause movement of the seismic activity sensors embedded in the ground and this movement induces an acceleration-dependent change in the FBG gratings placed on the sensors. In multiple sensor configurations, the cable will be connected to the other sensors in the network. FBG sensors, sensor arrays and sensor methods are provided in several embodiments.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.