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Sonar (originally an acronym for SOund Navigation And Ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, communicate with or detect objects on or under the surface of the water, such as other vessels. Two types of technology share the name "sonar": passive sonar is essentially listening for the sound made by vessels; active sonar is emitting pulses of sounds and listening for echoes. Sonar may be used as a means of acoustic location and of measurement of the echo characteristics of "targets" in the water. Acoustic location in air was used before the introduction of radar. Sonar may also be used in air for robot navigation, and SODAR (an upward looking in-air sonar) is used for atmospheric investigations. The term sonar is also used for the equipment used to generate and receive the sound. The acoustic frequencies used in sonar systems vary from very low ( infrasonic) to extremely high ( ultrasonic). The study of underwater sound is known as underwater acoustics or hydroacoustics.

Sonar (band)

Sonar is the name of a Belgian musical group, combining rhythmic noise, soundscapes, and industrial music. It was formed as a side-project of noise artists Dirk Ivens and Patrick Stevens.

Sonar (comics)

Sonar is the name of two DC Comics supervillains.


Sónar is a three-day electronic and advanced music festival. It was founded in Barcelona in 1994 by Ricard Robles, Enric Palau, and Sergi Caballero. The festival has been divided into two parts since its inception: Sónar by Day and Sónar by Night.

Sonar (disambiguation)

Sonar or SONAR often refers to a technique that uses sound propagation under water.

Sonar may also refer to:

SONAR (Symantec)

SONAR is the abbreviation for Symantec Online Network for Advanced Response. Unlike virus signatures, SONAR examines the behavior of applications to decide whether they are malicious. SONAR is built upon technology Symantec acquired in its late 2005 purchase of WholeSecurity, a developer of behavioral anti-malware and anti-phishing software solutions in the United States.

Sonar (mobile application)

Sonar was a free mobile application which showed the user how they are connected to other individuals in a room via publicly available social media profiles and location information from Foursquare, Twitter, and Facebook.

Sonar (keelboat)

The Sonar is a 7 m (23 ft) one-design keelboat for three to five people. It is bermuda-rigged, with a large mainsail and a 100% jib. The class is recognised by the International Sailing Federation.

The Sonar showcased disabled sailing at the 1996 Paralympic Games where the sport was a demonstration event with just the Sonar. The Sonar has been the three person keelboat at every subsequent Paralympics. When being sailed by disabled it is crewed by 3, and sailed without a spinnaker. Instead, when running downwind a whisker pole is used to hold the jib out to windward for maximum exposed sail area. The Sonar is well suited for disabled sailing because of its large open cockpit making adaptations easy.

The Sonar was designed in 1979 by Bruce Kirby, designer of the popular Laser dinghy. Since then, over 800 boats have been built. Most of the fleet is in the USA, with smaller fleets in Britain and Canada. Since its adoption as a Paralympic class the Sonar has spread to many other countries as well.

The Sonar was inducted into the American Sailboat Hall of Fame in 2004.

Longman Dictionary of Contemporary English


▪ Observations of Freddy led them to conclude that dolphins use sonar while hunting.
▪ They used sonar in a search for the voice and data recorders and the aircraft engines, among other components.
▪ We used three kinds or sonar apparatus.
▪ In that case, the mud prevented investigators from using sonar to locate the voice and data recorders.
▪ There is another dark world where animals use sonar to find their way around.
▪ Navy salvage experts used sonar to help locate the area of submerged wreckage.
▪ A dolphin is able to produce sonar clicks by forcing air through special passages and sinuses in its head.
▪ And, the Navy is having trouble filling shipboard billets with enough sonar and fire control technicians, who require extensive schooling.
▪ Distinguishing between active sonar returns from mines and returns from rocks and debris on the sea floor is difficult.
▪ Navy salvage experts used sonar to help locate the area of submerged wreckage.
▪ Something in the loch has produced some very peculiar sonar traces on some very sophisticated equipment, and that something demands explanation.
▪ The sonar watch on the ticking device in the crashed bomber was now continuous.
▪ The Lowrance company introduced the first civilian sonar in 1957.
▪ They carry simple Kelvan Hughes sonar and Racal-Decca radar.


n. a measuring instrument that sends out an acoustic pulse in water and measures distances in terms of the time for the echo of the pulse to return; sonar is an acronym for sound navigation ranging; asdic is an acronym for anti-submarine detection investigation committee [syn: echo sounder, asdic]



n. 1 (context nautical English) echolocation 2 (context nautical English) A device that uses hydrophones (in the same manner as radar) to locate objects underwater.

Douglas Harper's Etymology Dictionary


apparatus for detection underwater, 1946, from first letters of "sound navigation ranging," on pattern of radar.

Usage examples of "sonar".

They have sonar, updraft and downdraft detection, aerofoil control, warpage control, and so forth and so forth.

At the aft end of the conn was a display console housing repeater panels for the sonar set and the firecontrol computer as well as the red handset of a NESTOR satellite secure-voice radio system.

Examples include sonar and firecontrol, fast speed reactor main coolant pumps, and the wardroom video machine.

Their long-range aircraft would be down for needed maintenance, and their submarines, cruising four hundred feet down, could keep their sonar watches in comfort.

Mary hunted for the distinctive sonar echo that would guide diem in, Peter stared through the exiguous windows.

And as the Santo Fado muttered around the protected areas of Georges Bank, Roberto engaged the sonar scope that made finding fish such a pleasure.

The refit of the Hawkbill had been a major accomplishment in this endeavor: the submarine had taken on an impressive array of sonar, seismic equipment, and a battery of other electronics intended for use by academic and governmental researchers.

The latest sonar plots and bathymetric charts from the Hawkbill were truly astounding.

As with many modern submarines, the sonar room of the Hawkbill was positioned forward of the sail, just below the weapons-loading hatch.

His sonar officer, David Hall, was a gem, the chief and his technicians outstanding, and they all understood why he enjoyed kibitzing in the background in that small space chock-full of the most sophisticated electronic gear available.

Their beds were pushed headboard to headboard so they could talk quietly at night and toss a Nerf ball back and forth between them in the dark to develop their sonar capabilities.

The orca sonar could transmit across significant distances and he was using that to keep in communication with the dispersed fleet.

Until the light was extinguished as an orca head popped into the opening and blasted him with sonar.

When his sonar picked up large swimming objects, he thought he had found his reluctant allies, but the approaching creatures turned out to be the sharks bearing Puna and her family.

The sondes were dropped more or less at random, aiming only at spots where the deep-probe radars and sonars had identified clusters of beings.