Category Archives: Underwater Acoustics and Sonar

This blog posts news about acoustics and sonar, including links to industry news and articles, and announcements of continuing education for professionals who are working in the sonar, noise and acoustics profession. It includes information about sounds impact on marine mammals and US and International regulations and guidelines.

This video is about a predator bird hunting a squirrel. Occasional we post things on the web just because we are impressed.

Occasional we post things on the web just because we are impressed. Look at this video and figure out how you would have filmed and created it.

It was forward by Captain Ray Wellborn who teaches ATIcourses Submarines and Anti-Submarine Warfare which covers submarines and hunting for submarines. This video is about a predator bird hunting  a squirrel. The visuals are amazing.

Large Displacement Unmanned Undersea Vehicle (LDUUV)- Experts To Report On October 16, 2013

The rise of Unmanned Aerial Vehicles (UAVs) is driving the development on unmanned technologies in other areas.  Unmanned aerial vehicles (UAVs) are becoming so commonplace that the FAA is hard-pressed to come up with regulations to control their operations.

Unmanned marine vehicles, meanwhile, are becoming a hot technology topic, as military researchers push a program forward to develop a long-endurance unmanned underwater submarine.

The experts are scheduled to report on this project on October 16 at Alion Science and Technology Inc.

On the schedule of the briefings:

LDUUV vision and missions

program schedule


technology risks and payoff

technology development and transfer



testing requirements

Q & A session

You can register by emailing Navy’s Ron Merlene at

Read more here.

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Detecting Quiet Diesel Electric Submarines

This is an article worth reading. You can also learn more by attending ATI’s sonar and acoustics courses.

This is a quote from the summary.

There are 39 nations operating a total of 400 diesel electric subs. Only three of these nations (China, Iran, North Korea) are likely to use their subs against the U.S. or its allies. China has fifty of these boats, Iran has three (plus 25 much smaller mini-subs) and North Korea has 20 (plus 50 much smaller mini-subs). So the U.S. has to worry about 73 diesel electric subs and 75 mini-subs. But about half the full size subs are elderly, obsolete, and noisy. The same can be said for at least half the mini-subs. That leaves about 36 full size subs and 40 mini-subs that are a clear threat (though the older stuff can be a threat if you get sloppy). That’s a lot of subs, and they make the East Asian coast and the Persian Gulf dangerous places for American warships.

Moreover, the North Korean and Iranian fleets (and governments) are in decline, while China is pouring more cash into their armed forces. If there’s any diesel-electric boats the U.S. Navy has to be extremely concerned about, it’s the Chinese. While China continues to try and develop world class nuclear subs, they are also moving ahead in creating world class diesel electric boats.




Training budgets: Smaller is not an option


The debate on the budgets for the government organizations is pretty toxic in the US. Both US Navy and US Army alongside other organizations have declared budget shortfalls which effect many areas including training. Without commitment to training and learning new skills there can be no continuous improvement, which is one of the prime directives of any government or company.

The Applied Technology Institute (ATI) specializes in short course technical training in space, communications, defense, sonar, radar, systems engineering and signal processing. Since 1984 ATI has provided leading-edge public courses and on-site technical training to defense and NASA facilities, as well as DOD and aerospace contractors. The courses provide a clear understanding of the fundamental principles and a working knowledge of current technology and applications.


When your company does not want to pay for the training you really want, as an alternative, you can:

  • Spent your own personal money and funds; if you believe in it and then you will do it
  • Find a user group who are practicing the skills you desire
  • Don’t accept the classic answer from the boss, “How does X help the business?”. If the training is relevant to you achieving a goal of being a much better employee then of course it is relevant.
  • Find another organization to work for

A training manager with a good team can:

  • Fight for your team and their training; fight for your team’s budget and don’t let the senior management take it away
  • Give up your personal training for the entire year and suggest that they allocate the extra budget to training for your team members
  • Perhaps, it is time to evaluate the relationship with the preferred supplier of training. Has your firm been getting decent value from the PSL (preferred supplier list)?
  • Find alternatives to training like brown bag lunches and/or collaborate with other businesses

Everybody needs training and self-improvement.

Please share your opinion with us by commenting below.

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Was A Killer Whale Killed By NAVY Exercises?

Applied Technology Institute offers a short technical course, Underwater Acoustics For Biologists and Conservation Managers, on April 17-19, 2012 in Washington, DC area.  We thought the news below would be of interest to our readers.

It appears that yet another magnificent creature of the deep,  a member of the endangered southern resident killer whales, was killed by NAVY exercises.

The body of the three-year-old female whale,L112, known both as Sooke and Little Victoria, washed up on a beach near Long Beach, Washington, shortly after the Canadian navy was using sonar in Juan de Fuca Strait.

According to witnesses, sonar pings, which were recorded by a series of hydrophones, were preceded by an explosion.

The necropsy conducted by the experts shows that the whale died from “significant trauma”.

This caused an outrage in environmental community, including David Suzuki Foundation, Georgia Strait Alliance, Greenpeace, Living Oceans, Raincoast Conservation Foundation, Sierra Club B.C., Western Canada Wilderness Committee and the World Wildlife Fund.

Under Canada’s Species At Risk Act the killer whales are listed as endangered spices.

All of the above mentioned organizations call for ending of the military exercises in the a release of all information about activities in the area that might have contributed to Sooke’s death.

What is you opinion on this matter?

Please comment below.

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Want to listen to a whale song LIVE? Tune in to Whale FM!

If you are interested in whales and would like to know more about them, now is your chance.  Citizen Scientist Alliance launched a new project named The Whale Song Project or Whale FM.

Via “Hokumoanalani” (Star of the Heavenly Ocean) hydrophone that was launched off the coast of Hawaii in 2005.  Now with a help of the radio system, transmitter and audio feed up to 100 citizen scientists can listen to various whale songs.

After listening to the whale call citizen scientists are asked to listen to a number of potential matching calls from the project’s database. If a match is found, the citizen scientist clicks on that sound’s spectrogram and the results are stored.

The data generated by this project should help scientists to answer a number of questions regarding whale communication. For example, researchers want to know the size of the pilot whales’ call repertoire and whether repertoire size is a sign of intelligence. In addition, researchers seek to understand whether the two different types of pilot whales—long fin and short fin—have different call repertoires, and, if so, whether this signifies a distinct dialect.

If you would like to listen to the whale songs here are some Tune-In Links:

iTunes or Winamp:

Real Player:

Windows Media Player:


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Ocean Observing Systems (OOS) and March 11, 2011 Tsunami Warnings

Ocean Observing Systems (OOS) have many sensor to detect earthquakes and tsunamis.

Japan’s most powerful earthquake since records began has struck the north-east coast, triggering a massive tsunami. A massive 8.9 magnitude earthquake hit the Pacific Ocean nearby Northeastern Japan at around 2:46pm on March 11 (JST) causing damage with blackouts, fire and tsunami.

Cars, ships and buildings were swept away by a wall of water after the 8.9-magnitude tremor, which struck about 400km (250 miles) north-east of Tokyo.

A state of emergency has been declared at a nuclear power plant, where pressure has exceeded normal levels.

The following videos provide good information.

Probing the Ocean for Submarines – Additional Information

Title: Probing the Ocean for Submarines: A History of the AN/SQS-26 Long-Range Echo-Ranging Sonar
(2nd Edition)

Author: Thaddeus G. Bell

Publisher: Peninsula Publishing

ISBN: 978-0-932146-26-7

Pages: 264

Binding: Soft cover

This book presents the history of the design and development from 1955 to 1975 of the AN/SQS-26 echo-ranging sonar for submarine detection from ocean escorts (DEs). The sonar was the first to utilize long-range bottom reflection and convergence zone paths, in addition to the more conventional surface-duct paths. These long-range paths are little affected by submarine depth. In deep water a “bottom bounce” active detection range out to as far as 25 miles is possible, where the bottom is sufficiently reflective. In shallow water the bottom is normally reflective enough to permit echo ranging out to as much as 20 miles via multiple bottom reflections. If the water depth is sufficient, a “convergence zone” is also available from deep refraction paths converging over a narrow annular detection zone with an outer extent up to 40 miles from an echo-ranging source.

The book describes AN/SQS-26 echo-ranging detection performance using these long-range paths against surface ships of opportunity, U.S. submarines and Soviet submarines on patrol. Starting about 1975, digital upgrades of the original design were produced for destroyers, guided missile destroyers, and guided missile cruisers. The upgrades are currently being installed at this writing (2011) on the new construction of today’s DDG-51 class guided missile destroyers. In the early 1980s the major characteristics of this surface ship active sonar were also incorporated into the bow array sonar of USN submarines.

The historical information presented should be of interest to operational commands, sonar designers, research scientists, undersea warfare tacticians and those involved in resource-allocation decisions for research, development and production programs.

Virginia Class Submarine Summary

ATI Courses is scheduled to present technical training short course Submarines and Anti-Submarine Warfare scheduled to be presented in Columbia, MD on June 21-23, 2011.  We think our readers would be interested in the information below.

Designed by Electric Boat, the Virginia-class is being built jointly under a teaming arrangement between Electric Boat and Northrop Grumman Newport News in Virginia. In 1998, the U.S. Navy awarded a $4.2 billion contract for the construction of the first four ships of the class. Virginia is the first of these. Displacing approximately 7,800 tons with a length of 370 feet, Virginia is longer but lighter than the previous Seawolf-class of submarines. The 132-member crew can launch Tomahawk land-attack missiles from 12 vertical launch system tubes and Mark 48 advanced capability torpedoes from four 21-inch torpedo tubes. Virginia will be able to attack targets ashore with accurate Tomahawk cruise missiles and conduct covert long-term surveillance of land areas, littoral waters or other sea forces. Other missions will conduct include anti-submarine and anti-ship warfare, special forces delivery & support, and mine delivery and minefield mapping. With enhanced communications connectivity, Virginia also will provide battle group & joint task force support, with full integration into carrier battle group operations. The Virginia-class submarines surpasses the performance of any current projected threat submarine, ensuring US undersea dominance well into the next century. The Virginia class (or SSN-774 class) of attack submarines are the first US subs to be designed for a broad spectrum of open-ocean and littoral missions around the world. They were designed as a cheaper alternative to the Cold War era Seawolf-class attack submarines, and are slated to replace aging Los Angeles class subs, seventeen of which have already been decommissioned. The Virginias incorporate several innovations. Instead of periscopes, the subs have a pair of extendable “photonics masts” outside the pressure hull. Each contains several high-resolution cameras with light-intensification and infrared sensors, an infrared laser rangefinder, and an integrated Electronic Support Measures (ESM) array. Signals from the masts’ sensors are transmitted through fiber optic data lines through signal processors to the control center. The subs also make use of pump-jet propulsors for quieter operations.

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Ocean Observing Systems (OOS) and Tsunami Warnings

Ocean Observing Systems (OOS) have many sensors. One function is to detect earthquales using seismometers and hydrophones, and tsunamis using bottom pressure recorders.
A massive 8.9 magnitude earthquake hit the Pacific Ocean nearby Northeastern Japan at around 2:46pm on March 11 (JST) causing damage with blackouts, fire and tsunami.
These videos give some background information.