Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Engineers develop low-cost, highly sensitive underwater listening device

23.05.2005


Ocean-going acoustic sensor array to aid in national security, ocean research efforts



Jason Holmes, a mechanical engineering graduate student at Boston University and guest researcher at Woods Hole Oceanographic Institute, has devised a low-cost, highly sensitive array of underwater ears that is perking up interest in both homeland security and ocean research circles. Holmes’ device -- an underwater hydrophone array designed to be towed by a small, autonomous submarine -- can monitor for ocean-going threats to America’s waterways or for sound for ocean acoustics studies.

Holmes will present research on his underwater listening device in Vancouver on May 20 at the semi-annual meeting of the Acoustical Society of America.


The array combines sophisticated engineering with off-the-shelf hardware to create a relatively inexpensive but highly sensitive underwater listening device. The prototype comprises six underwater microphones, or hydrophones, spaced inside a 30-foot plastic tube filled with mineral oil. The array tube is filled with mineral oil to create neutral buoyancy, allowing the array to float behind the underwater towing vehicle.

Signals from the hydrophones are captured and stored on mini-disc recorders aboard the unpiloted submarine, which is called Remus. Designed by Woods Hole Oceanographic Institution, Remus looks like a small torpedo and can navigate autonomously underwater around obstacles and through harbors using GPS sensors, sonar, and electronic maps.

Listening arrays typically used by the military and ocean scientists are towed behind ships and are very long, the shortest being around 1,500 feet long, and are several inches in diameter. At 30 feet in length and 1.1 inches in diameter, the extremely compact prototype can easily be towed through the water by a small, quiet, battery-powered craft. The compact size of the towing sub and array make it easy for one or two people to launch the system, compared to the fully crewed ships required for conventional hydrophone systems.

Holmes originally developed the array to help him study how sound waves travel through shallow water, where sound is refracted by the bottom. Until recently, most acoustic ocean studies have been conducted in deep water, where the bottom has little effect on sound. Holmes constructed the hydrophone system to tackle the problem of how sound waves behave in shallow water, but the U.S. Navy saw the device as a potential security tool, one that is vastly less expensive than the multi-million dollar listening arrays currently in use. Parts for Holmes’ array cost a mere $4,000 and are available as off-the-shelf technology.

Holmes is now working with the military to further develop the array for underwater intelligence gathering. Holmes says his next project will comprise four underwater hydrophone arrays towed by a fleet of unpiloted subs that could travel up to 4 kilometers per trip. Holmes and his faculty advisor William Carey, a professor of aerospace and mechanical engineering in BU’s College of Engineering, say they envision a fleet of entirely autonomous listening subs will prowl the seas, returning to underwater recharging stations to upload their data and refresh their batteries.

"A lot of people were skeptical this would even work," Carey says. "But the way Jason has designed this array, this will change the way ocean measurements are made."

Ann Marie Menting | EurekAlert!
Further information:
http://www.bu.edu

More articles from Power and Electrical Engineering:

nachricht Silicon solar cell of ISFH yields 25% efficiency with passivating POLO contacts
08.12.2016 | Institut für Solarenergieforschung GmbH

nachricht Robot on demand: Mobile machining of aircraft components with high precision
06.12.2016 | Fraunhofer IFAM

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>