Featured Research

from universities, journals, and other organizations

Pinpoint Sound Beams Hunt Buried Land Mines

Date:
December 27, 2006
Source:
Massachusetts Institute Of Technology
Summary:
Researchers at MIT's Lincoln Laboratory are developing a highly pinpointed sound beam that can detect buried land mines from a safe distance. The new beam will use sound to seek out land mines like a bat uses sonar to hunt its prey.

MIT Lincoln Laboratory researchers are developing a sonic beam that seeks out buried mines the way bats seek out their prey.
Credit: Photo Jon Barron, MIT Lincoln Lab

Researchers at MIT's Lincoln Laboratory are developing a highly pinpointed sound beam that can detect buried land mines from a safe distance. The new beam will use sound to seek out land mines like a bat uses sonar to hunt its prey.

Related Articles


The researchers built a prototype detector and tested it at the Cold Regions Research and Engineering Laboratory Army Corps of Engineers land-mine facility in New Hampshire. They were able to detect both metal and plastic mines but said that the system will have to get a major boost in acoustic power before minefield searchers can use it safely.

Robert W. Haupt, a technical staff member at Lincoln Lab, explores innovative ways to find and reduce the large number of land mines abandoned in war-torn countries. An estimated 26,000 people are killed or maimed every year by 60 to 70 million undetected land mines in 70 countries. Those casualties include military troops but most are civilians--half of them children under age 16--who step on uncleared minefields after a war.

Many existing prototype mine detection systems can detect only metal, have limited range or are impractical in the field. "Reliable methods that quickly and accurately locate land mines made of metal and plastic, unexploded ordnance and other mine-like targets are desperately needed," Haupt said.

Haupt and fellow Lincoln Lab staff member Ken Rolt developed a high-powered sound transmitter that looks like a stop sign studded with 35mm film canisters or prescription pill containers. This is called a parametric acoustic array, and Haupt and Rolt have built one of the most powerful ones around.

The array is made up of ceramic transducers--devices that emit a powerful narrow acoustic beam at ultrasonic frequencies. One meter away, the ultrasonic pressure level measures 155 decibels--more acoustic power than a jet engine. Immediately outside the beam, the acoustic intensity dies away to almost nothing.

By a process know as self-demodulation, the air in front of the acoustic beam converts the ultrasound to much lower frequency audible tones that sound like extremely loud tuning forks. Unlike ultrasound, the low-frequency sound can penetrate the ground, causing detectable vibrations in the mine's plungers and membranes.

"The use of ultrasound allows us to make a very narrow and highly directional beam, like a sound flashlight," Haupt said. It would take a huge number of conventional loudspeakers to do the same trick, and they would weigh too much, take up too much space and use too much power to be practical, he said. Plus, they would deafen anyone within earshot. "Using a narrow sound beam, we can put sound just where we want it, and we can minimize sound levels outside the beam to avoid harming the operators or people nearby," he said.

Once the sound beam "hits" buried ordnance, the vibrations from the mine, resonating from the sound waves, push up on the ground and can be measured remotely with a laser system called a Doppler vibrometer. The sound signature of a mine looks like a mountain range of spikes compared with the flat-line response of the rocks and dirt around it.

"It turns out that mines will vibrate quite differently from anything else," Haupt said. "You can determine what types of mines there are--and which countries made them--by their unique signatures."

Haupt also is working with Oral Buyukozturk, professor of civil engineering at MIT, to tailor the system to detect damage in cement bridge piers from as far away as the shore.

This work is supported by Lincoln Laboratory's Line Funding and the Defense Advanced Research Projects Agency.


Story Source:

The above story is based on materials provided by Massachusetts Institute Of Technology. Note: Materials may be edited for content and length.


Cite This Page:

Massachusetts Institute Of Technology. "Pinpoint Sound Beams Hunt Buried Land Mines." ScienceDaily. ScienceDaily, 27 December 2006. <www.sciencedaily.com/releases/2006/12/061227093651.htm>.
Massachusetts Institute Of Technology. (2006, December 27). Pinpoint Sound Beams Hunt Buried Land Mines. ScienceDaily. Retrieved April 2, 2015 from www.sciencedaily.com/releases/2006/12/061227093651.htm
Massachusetts Institute Of Technology. "Pinpoint Sound Beams Hunt Buried Land Mines." ScienceDaily. www.sciencedaily.com/releases/2006/12/061227093651.htm (accessed April 2, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Thursday, April 2, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Voice-Controlled GPS Helmet to Help Bikers

Voice-Controlled GPS Helmet to Help Bikers

Reuters - Innovations Video Online (Apr. 1, 2015) Motorcyclists will no longer have to rely on maps or GPS systems, both of which require riders to take their eyes off the road, once a new Russian smart helmet goes on sale this summer. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com
Wound-Healing Laser Soon to Be a Reality Israeli Scientist

Wound-Healing Laser Soon to Be a Reality Israeli Scientist

Reuters - Innovations Video Online (Apr. 1, 2015) Israeli scientists says laser bonding of tissue allows much faster healing and less scarring. Amy Pollock has more. Video provided by Reuters
Powered by NewsLook.com
7-Year-Old Girl Gets 3-D Printed 'robohand'

7-Year-Old Girl Gets 3-D Printed 'robohand'

AP (Mar. 31, 2015) Although she never had much interest in prosthetic limbs before, Faith Lennox couldn&apos;t wait to slip on her new robohand. The 7-year-old, who lost part of her left arm when she was a baby, grabbed it as soon as it came off a 3-D printer. (March 31) Video provided by AP
Powered by NewsLook.com
Dutch Architects Show Off 3D House-Building Prowess

Dutch Architects Show Off 3D House-Building Prowess

Reuters - Innovations Video Online (Mar. 31, 2015) Dutch architects are constructing a 3D-printed canal-side home, which they hope will spark an environmental revolution in the house-building industry. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins