SITE SEARCH:
video overview
ADS

IIr Associates, Inc.
Publisher of The Virginia Engineer

Print-Publishing Services
Web Site Design-Coding-Hosting
Business Consulting

Phone: (804) 779-3527
sales@iirassoc.com
iirassoc.com

NEWS
Fiber Optic Cables Detect Tunnel Excavation
March 2, 2009

With the same type of fiber optic cables used in telecommunications systems, researchers from the Technion-Israel Institute of Technology have developed a way to detect and pinpoint the excavation of tunnels during times of war, such as those used for smuggling weapons into Gaza.

Principal researchers Dr. Assaf Klar and Dr. Raphael Linker, both of the Technion Faculty of Civil and Environmental Engineering, say the system is capable of locating even narrow tunnels at depths greater than 60 feet with a limited number of false alarms.

“Tunnel excavation is accompanied by the release of stresses that cause permanent – though very tiny – displacements and strains in the ground,” says Dr. Klar. “If you can measure these strains in the soil with sensitive equipment, you can find the tunnel’s location.” Tunnel excavation has a distinctive signal that is very different from those of disturbances, he adds.

The research lays the groundwork for the initial stages of an underground fence based on an existing technology called BOTDR (Brillouin optical time domain reflectometry) that makes it possible to measure fiber distortion along 15 miles using one device.

The proposed system is based on “wavelet decomposition” of the continuous BOTDR signal, a process that breaks down the signal profile into simpler shapes, and then filters out any irrelevant signals (“noise”). The signals that remain are then characterized by a neural network that has been trained to locate tunnels using computer simulation of tens of thousands of profiles, including disturbances not related to tunneling (examples include raindrops).


  ------   News Item Archive  -----  
 
 
The Virginia Engineer MobileOur Mobile site
m.vaeng.com
The Virginia Engineer on facebook
The Virginia Engineer RSS Feed