Border securityUnderground security tech to revolutionize border security

Published 15 December 2010

The University of Arizona College of Engineering is testing an invisible border monitoring system that could revolutionize the way the U.S. conducts homeland security; the border-monitoring system, known as Helios, consists of laser pulses transmitted through fiber-optic cables buried in the ground that respond to movements on the surface above; a detector at one or both ends of the cable analyzes these responses; Helios is sensitive enough to detect a dog and can discriminate between people, horses, and trucks

A unique underground surveillance system tested by University of Arizona researchers could be used to watch the entire U.S.-Mexico border continuously.

The border-monitoring system, known as Helios, consists of laser pulses transmitted through fiber-optic cables buried in the ground that respond to movements on the surface above. A detector at one or both ends of the cable analyzes these responses.

Helios is sensitive enough to detect a dog and can discriminate between people, horses, and trucks. The system can be set to avoid being triggered by small animals and can also tell if people are running or walking, or digging, and in which direction.

Zonge, a geophysical engineering company based in Tucson, Arizona, recently installed a Helios test system in the desert near Tucson. The University of Arizona’s Lowell Institute for Mineral Resources is leading the project to evaluate Helios as a tool for border surveillance, assisted by the UA National Center for Border Security and Immigration.

This is not new technology. Such systems are known as smart sensors and are already used to monitor large engineering works such as dams, pipelines, bridges and highways for cracks or seismic damage and other unseen strain forces at work deep within structures.

The Helios system consists of fiber-optic cables, lasers and detectors and is more accurately described as a “distributed acoustic sensor.” It relies on the physics phenomenon of “optical backscattering” for its operation and is made by the British company Fotech Solutions.

It’s all a matter of scale,” said Scott Urquhart, Zonge president and senior geophysicist, talking about the shift from detecting seismic events to measuring tiny subsurface vibrations caused by desert wildlife, both two- and four-legged.

When very small vibrations hit the fiber-optic cables, the cables are slightly distorted,” Urquhart said. “This distortion creates a unique signature change in the laser pulses, which can be detected by the Helios unit.”

Urquhart said the Zonge team buried several types of cable at the desert test location. “Each had different properties in terms of flexibility or type of shielding,” he said. “The advantage of a Kevlar cable, of course, versus a steel cable, is that the Kevlar cable cannot be found with a metal detector.”

Nor does digging up the cable and cutting it clean through stop the system working, provided a Helios unit is connected to both ends of the cable, Urquhart said. “We can detect people digging up the cable, and even if they