Category Archives: Acoustics & Sonar

NASA launches Aquarius/SAC-D from Vandenberg Air Force Base on June 10, 2011

Aquarius will measure salinity by sensing thermal microwave emissions
from the water’s surface with three microwave instruments called
radiometers. When other environmental factors are equal, these
emissions indicate the saltiness of surface water. A microwave radar
scatterometer instrument will measure ocean waves that affect the
precision of the salinity measurement. Because salinity levels in the
open ocean vary by only about five parts per thousand, Aquarius will
be able to detect changes as small as approximately two parts per
10,000, equivalent to about one-eighth of a teaspoon of salt in a
gallon of water.

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How does the spring sounds under the Arctic seas?

Surprisingly loud and cacophonous believe it or not!  Although completely covered with ice on the surface with no signs of life these waters are filled with various animals.  Acoustic communication is key in a dark, ice-covered environment.  With the help of the hydrophone scientists are monitoring the sounds made by various aquatic life forms in the Arctic.

A hydrophone is a microphone designed to be used underwater for recording or listening to underwater sound. Most hydrophones are based on a piezoelectric transducer that generates electricity when subjected to a pressure change.



So, what do they hear?

  • Trills of the bearded seals
  • Moans and grunts of the bowhead whales
  • Whistles of the beluga whales


The reason for all this cacophony is that sounds propagates well in water and covers longer distances.

There is a lot of shipping noise in this area of the ocean, which causes some animals to gradually change the frequency of their calls.  They start calling at higher frequencies, to escape the shipping noise.

Read more here.



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Teledyne RD Instruments releases Velocity Software for ADCP

What is ADCP?

An Acoustic Doppler Current Profiler (ADCP or ADP) is a sonar that attempts to produce a record of water current velocities for a range of depths. They are made of ceramic materials, and contain transducers, an amplifier, a receiver, a mixer, an oscillator, a clock, a temperature sensor, a compass, a pitch and roll sensor, and computer components to save the information collected. ADCPs can be configured in many ways: side-listening, into rivers and canals for long term continuous discharge measurements, downward-listening and mounted on boats for instantaneous surveys in the ocean or rivers, and mounted on moorings, or the seabed for long term current & wavestudies. They can stay underwater for years at a time, and have a battery back for an energy source. The sonar is used for oceanography, estuary, river and stream flow measurement, and weather forecasting.

Who is Teledyne RD Instruments?

Teledyne Technologies Incorporated is a leading provider of sophisticated electronic components and subsystems, instrumentation and communications products, including defense electronics, monitoring and control instrumentation for marine, environmental and industrial applications, harsh environment interconnect products, data acquisition and communications equipment for air transport and business aircraft, and components and subsystems for wireless and satellite communications.

What is the big news?

The release of the new Sentinel V (platform for interacting with your ADCP) is complimented by the release of the new pre-deployment Velocity Software.  Velocity software is an all-purpose, real-time planning tool with an interface simple yet powerful interface.  The main features are:

  • Intricate 2D and 3D graphs including:
    • Time series graphs
    • Contour graphs
    • Profile graphs
    • 3D surface / contour / profile graphs
  • Basic/conventional processing features including averaging, coordinate transforms, and velocity reference
  • Comprehensive, advanced, and fully customizable data processing engine
  • A comprehensive log of all loaded and recent data files
  • Export to multiple output formats

Read more here.


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ATI Offers Advanced Courses Sonar and Submarine Engineering

Do you Need Active or Passive Sonar?
Do you Need Active or Passive Sonar?
Video Clip: Click to Watch
Advanced Topics in Underwater Acoustics and Warfare

From active versus passive sonar to nuclear versus diesel submarines; how are you keeping up with the latest advances in underwater acoustics and warfare?
These two four-day short courses summarize both basic and “leading-edge” topics. In each class, the basics principles are reviewed and then current achievements and challenges are addressed.

The aim of the instructors is to make available practical results and lessons-learned in a tutorial form suitable for a broad range of people working in underwater acoustics and warfare. The course is designed for sonar systems engineers, combat systems engineers and undersea warfare professionals who wish to enhance their understanding and become familiar with the “big picture”.

Why not take a short course from ATI?

Since 1984, the Applied Technology Institute (ATI) has provided leading-edge public courses and onsite technical training. ATI short courses are less than a week long and are designed to help you keep your professional knowledge up-to-date. Our courses provide a practical overview of space and defense technologies which provide a strong foundation for understanding the issues that must be confronted in the use, regulation and development of complex systems.

Whether you are a busy engineer, a technical expert or a project manager, you can enhance your understanding of complex systems in a short time. You will become aware of the basic vocabulary essential to interact meaningfully with your colleagues.

Course Outline, Samplers, and Notes

These two advanced courses provide an in-depth treatment, taught by experts in the field, of the latest results in a selection of core topics of underwater acoustics and warfare.

After attending either of these courses, you will receive a full set of detailed notes from the class for future reference, as well as a certificate of completion. Please visit our website for more valuable information.


Course Objectives:

• Provide a general understanding of ocean acoustics and sonar principles

• Make attendees conversant with all aspects of ocean acoustics and sonar technology, engineering and performance assessment in the context of naval applications.

• Provide detailed, critical knowledge for understanding of basic concepts in ocean acoustics, physics and modeling, transduction technology and engineering, processing for sonar signal detection and estimation, and sonar system design and performance assessment.

• Provide understanding of the design, development and use of the acoustic propagation modeling software.

• Provide information and perspectives on new and emerging sonar technology and techniques and new sonar system configurations and functions.


Advanced Undersea Warfare (USW) covers the latest information about submarine employment in future conflicts. The course is taught by a leading innovator in submarine tactics. The roles, capabilities and future developments of submarines in littoral warfare are emphasized.

The technology and tactics of modern nuclear and diesel submarines are discussed. The importance of stealth, mobility, and firepower for submarine missions are illustrated by historical and projected roles of submarines. Differences between nuclear and diesel submarines are reviewed. Submarine sensors (sonar, ELINT, visual) and weapons (torpedoes, missiles, mines, special forces) are presented.

Advanced USW gives you a wealth of practical knowledge about the latest issues and tactics in submarine warfare. The course provides the necessary background to understand the employment of submarines in the current world environment.

This short course is valuable to engineers and scientists who are working in R&D, or in testing of submarine systems. It provides the knowledge and perspective to understand advanced USW in shallow water and regional conflicts.

Determine for yourself the value of this course before you sign up.

Slide Sampler USW#1

Slide Sampler USW #2

About ATI and the Instructors

Our mission here at ATI is to provide expert training and the highest quality professional development in space, communications, defense, sonar, radar, and signal processing. We are not a one-size-fits-all educational facility. Our short classes include both introductory and advanced courses.

ATI’s instructors are world-class experts who are the best in the business. They are carefully selected for their ability to clearly explain advanced technology.

ATI’s Advanced Topics In Underwater Acoustics Course Instructors

Dr. Duncan Sheldon earned his PhD Degree in 1969. He has over twenty-five years’ experience in the field of active sonar signal processing. His experience includes real-time direction at sea of surface sonar assets during ‘free-play’ NATO ASW exercises. He was also a sonar supervisor during controlled and ‘free-play’ NATO ASW exercises.

Paul C. Etter has worked in the fields of ocean-atmosphere physics and environmental acoustics for the past thirty- five years supporting federal and state agencies, academia and private industry. He is the author or co-author of more than 180 technical reports and professional papers addressing environmental measurement technology, underwater acoustics and physical oceanography. Mr. Etter is the author of the textbook Underwater Acoustic Modeling and Simulation (3rd edition).

Dr. Harold “Bud” Vincent has served on active duty on fast attack and ballistic missile submarines, worked at the Naval Undersea Warfare Center, and conducted advanced R&D in the defense industry. Dr. Vincent received the M.S. and Ph.D. in Ocean Engineering (Underwater Acoustics) from the University of Rhode Island. His teaching and research encompasses underwater acoustic systems, communications, signal processing, ocean instrumentation, and navigation. He has been awarded four patents for undersea systems and algorithms.

Dr. John P. Ianniello received his Ph. D. Degree in Physical Oceanography from the University of Connecticut in 1977. He has been a member of the Underwater Acoustics Signal Processing Committee of the IEEE Signal Processing Society since 1980. He has received a number of awards including the American Society of Naval Engineers Solberg Award for Individual Research in 1998, and the Department of the Navy Meritorious Civilian Service Award in 2000. His recent research has specialized in the processing of array data from Autonomous Undersea Vehicles.

ATI’s Advanced Undersea Warfare Course Instructors

Capt. James Patton (USN ret.) is President of Submarine Tactics and Technology, Inc. and is considered a leading innovator of pro- and anti-submarine warfare and naval tactical doctrine. His 30 years of experience includes actively consulting on submarine weapons, advanced combat systems, and other stealth warfare-related issues to over 30 industrial and government entities.

Commodore Bhim Uppal former Director of Submarines for the Indian Navy and he is now a consultant with American Systems Corporation. He has direct experience onboard FOXTROT, KILO, and Type 1500 diesel electric submarines. He has over 25 years of experience in diesel submarines with the Indian Navy and can provide a unique insight into the thinking, strategies, and tactics of foreign submarines. He helped purchase and evaluate Type 1500 and KILO diesel submarines.

Times, Dates, and Locations

Either of these courses can be scheduled on-site at your facility. For the times, dates and locations of all of our short courses, please access our schedule.

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Humpback Whales- DJ’s of the seas?

Are Humpback Whales DJ’s of the seas?

ATI’s Underwater Acoustics For Biologist s and Conservation Managers course is scheduled to be presented on June 13-16, 2011 in Columbia, MD. We think the news below would be of interest to our readers and potential students.

New Australian study published in Current Biology on April 14, 2011 says “yes”. The 11 year long study was conducted in the South Pacific. As it turns out, humpback whales change their song overtime to stand out amongst other whales and appeal to female whales. There is something of a fashion trade in whale songs: one whale changes his song and soon enough all the other whales follow suit. This behavior has never been observed in any other non-human species on the planet.

Here are the highlights of the study:

· Humpback whale songs have repeatedly moved east across the South Pacific

· The songs moved across the region in a series of cultural waves

· The waves frequently caused complete “cultural revolution” of the song

· The scale, rate, and repetition of these cultural changes are unparalleled

The humpback whale (Megaptera novaeangliae) is a species of baleen whale. One of the larger rorqual species, adults range in length from 12–16 metres (39–52 ft) and weigh approximately 36,000 kilograms (79,000 lb). The humpback has a distinctive body shape, with unusually long pectoral fins and a knobbly head. It is an acrobatic animal, often breaching and slapping the water. Males produce a complex whale song, which lasts for 10 to 20 minutes and is repeated for hours at a time.

Read more here

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Is Traffic Noise Ruining Your Health?

World Health Organization (WHO) says “yes” in their latest report released in late March. According to the studies conducted in Europe traffic noise is the second biggest environmental problem affecting our health in Europe, after air pollution. Traffic noise level higher than 60dB cause 1.8% of heart attacks in the populations studied. It is imperative that the traffic noise should be reduced. Environmental Protection UK has recently launch a Campaign For Better Tires which encourages drivers to purchase better tires that are quieter. The European Commission is expected to release a proposal in June for more stringent vehicle noise standards, and from November 2012 new regulations for stricter tyre noise levels and tyre labeling for noise come into force.
Noise health effects are the health consequences of elevated sound levels. Elevated workplace or other noise can cause hearing impairment, hypertension, ischemic heart disease, annoyance and sleep disturbance. Changes in the immune system and birth defects have been attributed to noise exposure, but evidence is limited. Although some presbycusis may occur naturally with age, in many developed nations the cumulative impact of noise is sufficient to impair the hearing of a large fraction of the population over the course of a lifetime. Noise exposure has also been known to induce tinnitus, hypertension, vasoconstriction and other cardiovascular impacts. Beyond these effects, elevated noise levels can create stress, increase workplace accident rates, and stimulate aggression and other anti-social behaviors. The most significant causes are vehicle and aircraft noise, prolonged exposure to loud music, and industrial noise. Road traffic causes almost 80% of the noise annoyances in Norway.
The social costs of traffic noise in EU22 are over €40 billion per year, and passenger cars and lorries (trucks) are responsible for bulk of costs. Traffic noise alone is harming the health of almost every third person in the WHO European Region. One in five Europeans is regularly exposed to sound levels at night that could significantly damage health.
Noise is also a threat to marine and terrestrial ecosystems.

Read more here:

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Does Sonar Testing Causes Whales To Beach Themselves?

The new concrete evidence was recently published by Peter Tyack of the Woods Hole Oceanographic Institution in the PLos One journal. Dr. Tyack and his colleagues describe a study in the Bahamas where they used underwater microphones to monitor “clicks” emitted by Blainville’s beaked whales while hunting. The whales that were hunting around Navy’s test range started to emit fewer “clicks” as soon as the sonar exercises began and then swam away miles away from the sound. They did return to the same spot a few days later.
The problem is that sometimes the whales are unable to get out of the way of sonar quickly enough. The mid-frequency sonar blasts may drive certain whales to change their dive patters in a way their bodies can’t handle, causing fatal injuries. In fact, many of the beached whales have suffered physical trauma, including bleeding around brain, ears and other tissues. These are symptoms similar to “the bends”- the condition that can kill scuba divers if they surface too quickly.
On the occasions listed below testing of mid-frequency to low-frequency active sonar was conducted in the area.

  • 1996: 12 Cuvier’s beaked whales beached in Greece
  • 1999: 4 beaked whales beached in the US Virgin Islands
  • 2000: 3 beaked whales beached in Madeira
  • 2002: 14 different whales beached in the Canary Islands

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