Vibration Detection

[AnGrz_Z_K_Jailer]

3-D Seismic Sensors Form Web Against Intruders

NETANYA, Israel - A small, 5-year-old Israeli company appears to have breached the technological barrier that, until now, has limited the ability of microphones, geophones and other off-the-shelf seismic sensors to reliably detect, classify and locate subterranean and surface infiltrations.

Now undergoing prototype testing by Spider Technologies Security (SpiderTech), the new seismic-based perimeter protection system - called Tarantula - creates an underground web of small, self-processing, three-dimensional sensors to detect digging, walking or motorized movement at about twice the ranges of existing systems.

Field tests in Israel and elsewhere have detected human targets at distances of about 30 meters, developers here said. Ranges are significantly longer - a minimum of 100 meters - for light vehicles, whereas heavy vehicles can be detected at a minimum of 300 meters, they say.

Like its namesake, SpiderTech's Tarantula uses its web as a tripwire alert against approaching intruders. And like the invertebrate, the high-tech Tarantula relies not on sight, but on sensitive hairlike extensions to feel out potential danger. In this case, individual sensors act as the creature's vibration-sensitive hairy legs, separating out environmental noise, classifying targets by seismic signature and pinpointing - within five meters - the location of approaching threats both on the surface and underground.

Under the preliminary deployment concept, sensors are buried about 50 centimeters underground at 40-meter intervals, forming a weblike array that is controlled by a single exchange unit, or SpiderTech Web (STW). Each STW can control up to 200 such sensors, while the envisioned system architecture allows for stacking of up to another 200 STWs, all of which are to be linked to a centralized PC-based command-and-control system.

What distinguishes Tarantula from other stealthy, seismic-based sensors, developers said, is its patented SpiderTech Sensor (STS), which includes three pairs of acceleration transducers - one pair for each axis, enabling full three-dimensional detection. These powerful accelerometers combine differential signals culled from each of the three axes into a virtual, single-point 3-D measurement.

Data processors integrated into each STS initiate detection, reduce environmental clutter, calculate the direction and estimated time of arrival and autonomously classify approaching threats. Because raw data is processed internally in each STS, the system does not suffer bottlenecks that occur in legacy systems, where several sensors are connected via main processing units, said Sever Mican, SpiderTech's chief technical officer.

"Until today, seismic-based systems offered limited strategic value due to a number of factors, including very high false-alarm levels, bottlenecks between sensors and processing units, and their inability to detect and classify targets in all environments at meaningful ranges," Mican said.

According to Mican, SpiderTech's 3-D, single-point transducer allows a very high signal-to-noise ratio irrespective of operational environment, a feature that drives false-alarm rates down below 10 percent.

Elkana Pressler, SpiderTech product and marketing director, said the company has been working with Israel's Ministry of Defense, the U.S. Department of Homeland Security and other potential customers to demonstrate system capabilities in a variety of operational terrains. "We're working in all types of environments - sand, moist soil, craggy topography, you name it - and the data we've collected is very promising," he said.

With regard to potential U.S. customers, Pressler said the firm is coordinating with SAIC to respond to U.S. government requests for information. "We've responded to Homeland Security's interest in tunnel detection. Our technology demonstration to them showed that we can accurately identify people moving underground even amid intense ground clutter. We're expecting promising challenges in the coming months."

Mican said field tests have demonstrated the system's ability to cancel out noise from multiple sources in isolated as well as congested environments.

"Differentiating between environmental and cultural noises and the threat signals can be extremely challenging. The system needs to be relatively immune to soil type, and it must be able to localize and track targets amid all kinds of [clutter], including wind, rainfall, waves, airports, heavily trafficked areas and even passing trains," he said.

With each smart 3-D sensor measuring 140 millimeters in height and 105 millimeters around, the system is relatively lightweight, easy to install, and requires no continuous calibration, Pressler said. It can be deployed as a stand-alone protective barrier or as part of a package operating in conjunction with optical, thermal, radar and other technologies, he said.

As for cost, Pressler said the company expects its virtual, underground system to be competitive with physical barriers and other early warning solutions, which run in the midrange at about $100 per meter. "We aim to offer a high-performance, cost-effective supplement to physical protection, and we're getting there," he said.


Agreement with Rada

SpiderTech is expected to soon announce a collaboration agreement with Israel's publicly traded Rada Electronic Industries Ltd., under which the internationally known defense electronics company will help market and manufacture Tarantula and related technologies.

"Of all the companies involved in seismic sensing and virtual perimeter security, this one jumps out in its potential for military, government and commercial users worldwide," said Zvika Alon, Rada chief executive officer. "We're excited to be involved in this emerging technology."

In Israel alone, the SpiderTech system is a strong candidate to defend hundreds of kilometers of open borders with Egypt, from the Mediterranean to the Red Sea, and with Jordan, from the Dead Sea to the Red Sea, said Rada Chairman Herzl Bodinger, a former Israel Air Force commander.

"This is one of the capabilities I've identified as imperative for the defense of Israel. Sadly, we've already suffered tremendously from terrorist tunnels and underground infiltrations, and this threat will surely grow in the years to come," Bodinger said.

As for the international market, aside from the obvious border control and homeland security applications, Bodinger cited the energy sector, where power plants, gas fields and other critical facilities are vulnerable to terrorism, sabotage and theft. Similarly, airfields, seaports, railways, water reservoirs and sensitive commercial sites are potential markets for Tarantula and derivative technologies.

"In gross, simplistic terms, they've found a way to locate and track a mouse crossing the street in New York City ... and they promise to do this with minimal infrastructure and at a very low cost," Bodinger said.

A retired Israeli Army colonel who continues to advise Israel's MoD on technology development matters said the Ministry's Research and Development Directorate has imposed extremely high performance standards in its ongoing evaluation of the SpiderTech system.

"We've been disappointed in the past by seismic-based systems, so we want to see a lot more data before declaring it mature enough to proceed to [full-scale development]," he said. "But from what we've seen so far, the data is encouraging." ■

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Link : Vibration Detection - Defense News