Sonar

Definition: Sonar

Sonar

Noun

1. 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 SOund NAvigation Ranging; asdic is Anti-Submarine Detection Investigation Committee).

Date "sonar" was first used in popular English literature: sometime before 1991. (references)

Specialty Definition: Sonar

Domain	Definition
Aerospace	(From sound, navigation, and ranging.) A method or system, analogous to radar used under water, in which high-frequency sound waves are emitted so as to be reflected back from objects, and used to detect the objects of interest. Called asdic by the British. (references)
Mining	The method or equipment for determining, by underwater sound, the presence, location, or nature of objects in the sea. The word sonar is an acronym derived from the expression SOund NAvigation and Ranging. (references)
Source: compiled by the editor from various references; see credits.

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Specialty Definition: Sonar

(From Wikipedia, the free Encyclopedia)

Sonar (sound navigation and ranging) is a technique that uses sound propagation under water to navigate or to detect other watercraft. There are two kinds of sonar, active and passive.

Active sonar

Active sonar creates a pulse of sound, often called a "ping", and then listens for reflections of the pulse. To measure the distance to an object, one measures the time from emission of a pulse to reception. To measure the bearing, one uses several hydrophones, and measures the relative arrival time to each in a process called beam-forming.

The first active sonar technology was originally called ASDIC after the "Allied Submarine Detection Investigation Committee".

The pulse may be at constant frequency or a chirp of changing frequency. If a chirp, the receiver correlates the frequency of the reflections to the known chirp. The resultant processing gain allows the receiver to derive the same information as if a much shorter pulse of the same total power were emitted. In general, long-distance active sonars use lower frequencies. The lowest have a bass "BAH-WONG" sound.

The most useful small sonar looks roughly like a waterproof flashlight. One points the head into the water, presses a button, and reads a distance. Another variant is a "fishfinder" that shows a small display with shoals of fish. Some civilian sonars approach active military sonars in capability, with quite exotic three-dimensional displays of the area near the boat. However, these sonars are not designed for stealth.

When active sonar is used to measure the distance to the bottom, it is known as echo sounding.

Sonar and marine animals

Some marine animals, such as whales and dolphins, use echolocation systems similar to active sonar to locate predators and prey. It is feared that sonar transmitters could confuse these animals and cause them to lose their way, perhaps preventing them from feeding and mating. A recent article on the BBC website (see below) reports findings published in the Journal Nature to the effect that military sonar may be inducing the whales to experience decompression sickness (and resultant beachings).

High-powered sonar transmitters can kill marine animals. In the Bahamas in 2000, a trial by the US Navy of a 230 decibel transmitter in the frequency range 3000-7000 hertz resulted in the beaching of sixteen whales, seven of which were found dead. The Navy accepted blame in a report published in the Boston Globe on 1/1/2002. However, at low powers, sonar can protect marine mammals against collisions with ships.

Passive Sonar

Passive sonars listen without transmitting. They are usually military (although a few are scientific).

Sonar in freshwater lakes is different in operation from sonar at sea. In salt water sonar operation is affected by temperature. Ocean temperature varies with depth, but at between 30 and 100 metres there is often an marked change, called the thermocline, dividing the warmer surface water from the cold, still waters that make up the rest of the ocean. Regarding sonar, a sound originating from one side of the thermocline tends to be reflected off the thermocline, unless it is very noisy. The thermocline is not present in shallower coastal waters. Pressure also affect sound propagation as convergence zones (CZ).

Sound waves that are radiated down into the ocean bend back up to the surface in great arcs due to the effect of pressure on sound. Under the right conditions these waves will then reflect off the surface and repeat another arc. Each arc is called a CZ annulus. CZs are found every 33 nm, forming a annular pattern of concentric circles around the sound source. Sounds that can be detected for only a few miles in a direct line can therefore also be detected hundreds of miles away. The signal is naturally attenuated but modern sonar suites are very sensitive.

Identifying sound sources

Military sonar has a wide variety of techniques for identifying a detected sound. For example, U.S. vehicles usually operate 60Hz alternating current power systems. If transformers are mismounted (without proper vibration insulation from the hull), or flooded, the 60Hz sound from the windings and generators can be emitted from the submarine or ship, helping to identify its nationality. In contrast, most European submarines have 50Hz power systems. Intermittent noises (such as a wrench being dropped) may also be listened for.

Passive sonar systems usually have large sonic databases. A computer system frequently uses these databases to identify classes of ships, actions (i.e. the speed of a ship, or the type of weapon released), and even particular ships. Most navies continuously update the information in these databases.

Noise

Passive sonar on vehicles is usually severely limited because of noise generated by the vehicle. For this reason, many submarines operate nuclear reactors that can be cooled without pumps, using silent convection, or fuel cells or batteries, which can also run silently. Vehicles' propellers are also designed and precisely machined to emit minimal noise. High speed propellers often create tiny bubbles in the water, and this cavitation has a distinct sound.

The sonar hydrophones may be towed behind the ship or submarine in order to reduce the effect of noise generated by them. Towed units also combat the thermocline, as the unit may be towed above or below the thermocline.

For many years, the United States operated a large set of passive sonar arrays at various points in the world's oceans. As permanently mounted arrays in the deep ocean, they were very quiet.

In war-time, emission of an active pulse is so compromising for a submarine's stealth that it is considered a very severe breach of tactics.

The display of most passive sonars used to be a two-dimensional waterfall display. The horizontal direction of the display is bearing. The vertical is frequency, or sometimes time. Another display technique is to colour-code frequency-time information for bearing. More recent displays are generated by the computers, and mimic radar-type plan position indicator displays.

Abbreviations & Acronyms: Sonar

The following table is compiled from various sources, across various languages. When English abbreviations or acronyms come from a non-English source, this is noted.
Entry	Source	Expression	Field
sonar	English	Sound navigation and ranging	Telecom
SONCM	English	Sonar countermeasures and deception	N/A
Source: compiled by the editor, based on several corpora (additional references).

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Synonyms: Sonar

Synonyms: asdic (n), echo sounder (n). (additional references)

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Synonyms within Context: Sonar

Context	Synonyms within Context (source: adapted from Roget's Thesaurus).
Depth	Sonar, side-looking sonar; bathometer.
Measurement	Bathometer, galvanometer, heliometer, interferometer, odometer, ombrometer, pantometer, pluviometer, pneumatometer, pneumometer, radiometer, refractometer, respirometer, rheometer, spirometer, telemeter, udometer, vacuometer, variometer, viameter, thermometer, thermistor (heat), barometer (air), anemometer (wind), dynamometer, goniometer (angle) meter; landmark; (limit); balance, scale; (weight); marigraph, pneumatograph, stethograph; rain gauge, rain gage; voltmeter(volts), ammeter(amps); spectrophotometer (light absorbance); mass spectrophotometer(molecular mass); geiger counter, scintillation counter(radioactivity); pycnometer (liquid density); graduated cylinder, volumetric flask (volume); radar gun (velocity); radar (distance); side-looking radar (shape, topography); sonar (depth in water); light meter (light intensity); clock, watch, stopwatch, chronometer (time); anemometer (wind velocity); densitometer (color intensity).
Source: adapted from Roget's Thesaurus.

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Crosswords: Sonar

English words defined with "sonar": asdic ♦ echo sounder ♦ pinger. (references)

Specialty definitions using "sonar": bottom bounce ♦ Computing Devices Canada Ltd., contact lost ♦ DEEP SUBMERGENCE VEHICLE OPERATOR, dynamic positioning ♦ Packet InterNet Groper ♦ sonar boomer seismic system, sonar capsule, submarine movement advisory authority. (references)

Non-English Usage: "Sonar" is also a word in the following languages with English translations in parentheses.

Czech (sonar), French (sonar), German (sonar), Italian (sonar), Occitan (call), Portuguese (sonar), Provencal (to call), Serbo-Croatian (sonar), Spanish (blare, blow, chink, clang, jangle, play, rattle, resound, ring, skirl, sonar, sound, speak, tintinnabulation, toot), Turkish (sonar).

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Modern Usage: Sonar

Domain	Usage
Screenplays	Conn, sonar! Crazy Ivan! (The Hunt for Red October; writing credit: Larry Ferguson) They're pinging away with their active sonar like they're looking for something, but nobody's listening. (The Hunt for Red October; writing credit: Larry Ferguson) We will pass through the American patrols, past their sonar nets, and lay off their largest city, and listen to their rock and roll while we conduct missile drills. (The Hunt for Red October; writing credit: Larry Ferguson)
Lyrics	But I still feel you pulse like sonar from the days in the waves (Never Let You Go; performing artist: Third Eye Blind)
Movie/TV Titles	Sonar Kathi (1958)
Source: compiled by the editor from various references; see credits.

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Commercial Usage: Sonar

Domain	Title
Books	Principles of Radar and Sonar Signal Processing (Artech House Radar Library) (reference) Quick Start Sonar: Sonar (reference) SONAR 2 Power! (reference) Sonar for Practising Engineers (reference) SONAR Power! (reference) (more book examples)

Periodicals	Iee Proceedings - Radar Sonar & Navigation (reference) (more periodical examples)

Theater & Movies	Lowrance X-49 Sonar (reference) (more DVD examples; more video examples)

Music	Sonar Del Laberinto (reference) (more classical music examples; more popular music examples)

High Tech	CAKEWALK MUSIC SOFTW SONAR 2.0 (Windows) (reference) Cakewalk Sonar XL (reference) (more camera examples; more video game examples; more computer examples; more electronic examples; more software examples)
Source: compiled by the editor from various references; see credits.

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Photo Album: Sonar

Thumbnail	Description & Credit	Thumbnail	Description & Credit
	Early sidescan sonar record showing targets Tests run on HILGARD ASV-82. Credit: Coast & Geodetic Survey Historical Image Collection.		Sidescan sonar system on SURVEYOR Used to explore for offshore extension of San Andreas Fault. Credit: Coast & Geodetic Survey Historical Image Collection.
	Recovery of sidescan sonar system on SURVEYOR Used to explore for offshore extension of San Andreas Fault. Credit: Coast & Geodetic Survey Historical Image Collection.		V-fin served as underwater kite to bring sensor close to bottom Housed bottom penetration sonar Deployed off of EXPLORER. Credit: Coast & Geodetic Survey Historical Image Collection.
	Sonar image of the U. S. S. MONITOR. Credit: Sanctuaries.		A diagram of the old wiredrag system as developed by Nicholas Heck, Jean Hawley, and others in the U. S. Coast and Geodetic Survey. Prior to the development of sidescan sonar, this was the only method to find protrusions from the bottom that occurred between sounding lines. Credit: Sailing for Science - the NOAA Fleet Then and Now.
	Underway, circa 1960, after she had been refitted with a bow-mounted sonar. Credit: NAVY.		Underway at sea, circa the early 1960s, after she had been fitted with a bow-mounted sonar. Credit: NAVY.
	Underway on 8 April 1963, shortly before she deployed to the Mediterranean for a tour with the Sixth Fleet. She has an experimental retractable sonar fitted to her bow. Credit: NAVY.		"Crew members of the streamlined submarine USS Pickerel are shown beside a huge lei presented to the officers and men as the submarine docked at Pearl Harbor today, Nov. 4. She was among the first Pearl Harbor based submarines to return from the Korean War Zone." The original photograph was released by 14th Naval District PIO, and is dated 4 November 1950. The sailors are standing on Pickerel's bow, by her sonar dome and jackstaff. Credit: NAVY.
Source: pictures compiled by the editor from various references; see picture credits.

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Sounds Captioned with "Sonar".

Play	Caption
	Sonar blip.
Source: compiled by the editor from various references; see credits.

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Non-Fiction Usage: Sonar

Subject	Topic	Quote
Business		These include the Thunder 2000 multiple rocket launcher system (MRLS); the Hsiung-feng II all-weather anti-ship missiles; the Sky Bow II SAMs, long range multiple-target combat interdiction; Sky Sword II AAMs, which has a beyond-visual range and is capable of fire-and-forget; the vehicle-launched Sword I SAMs; artillery fire control systems, naval sonar systems, and electronic warfare systems. (references)
Human Rights	Russia	On October 3, 2000, Primorye Regional FSB authorities opened a criminal case against Vladimir Shchurov, Director of the Sonar Laboratory of the Pacific Oceanographic Institute. (references)
Source: compiled by the editor from ICON Group International, Inc.; see credits.

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Usage Frequency: Sonar

"Sonar" is generally used as a noun (singular) -- approximately 100.00% of the time. "Sonar" is used about 166 times out of a sample of 100 million words spoken or written in English. Its rank is based on over 700,000 words used in the English language. Some parts-of-speech are not covered due to the samples used by the British National Corpus. (note: percents less than one-hundredth of one percent have been omitted)

Parts of Speech	Percent	Usage per 100 Million Words	Rank in English
Noun (singular)	100%	166	24,220

Source: compiled by the editor from several corpora; see credits.

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Expression: Sonar

Expression using "sonar": passive sonar. Additional references.
Hypenated Usage
	Ending with "sonar": bat-sonar.
Source: compiled by the editor from various references; see credits.

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Frequency of Internet Keywords: Sonar

The following statistics estimate the number of searches per day across the major English-language search engines as identified by various trade publications. Hyperlinks lead to commercial use of the expression at Amazon.com.

Expression	Frequency per Day	Expression	Frequency per Day
sonar	822	lowrance sonar	9
cakewalk sonar	136	sonar herbicide	9
sonar xl	32	2.2 cakewalk sonar	8
side scan sonar	29	lfa sonar	8
sonar 2.0	26	cakewalk manual sonar	8
eagle sonar	24	sonar tire	8
sonar drum	23	cakewalk sonar 2.0	7
2.2 sonar	21	sonar system	7
249c mk sonar	20	2.2 sonar xl	7
festival sonar	18	sonar submarine	7
2003 sonar	16	sonar user	7
sonar xl 2.0	13	sonar vancouver	7
barcelona sonar	13	radar and sonar	7
bird humming sonar	13	fishing sonar	7
active frequency low sonar	12	sonar fish finder	7
sonar 2	11	sonar transducer	6
sidescan sonar	10	lounge sonar	6
baltimore sonar	10	sonar sound	6
history sonar	10	interphase sonar	6
cakewalk sonar xl	10	cakewalk download sonar	6
		sonar tutorial	6
Source: compiled by the editor from various references; see credits.

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Modern Translation: Sonar

Language		Translations for "sonar"; alternative meanings/domain in parentheses.
Albanian		pelengator zhurmash, hidrolokator. (various references)

Arabic		‏سونار جهاز في السفينة. (various references)

Bulgarian		хидролокатор. (various references)

Chinese		�"�波探侧器. (various references)

Czech		sonar. (various references)

Danish		passiv sonar (passive sonar), fremstilling af billede ved hjælp af sonar (sonar image processing). (various references)

Dutch		sonarbeeldinterpretatie (sonar image processing), passieve sonar (passive sonar). (various references)

Farsi		دستگاه کاشف زیردریاءی باامواج صوتی . (various references)

Finnish		passiivinen luotain (passive sonar). (various references)

French		sonar. (various references)

German		Schallmessgerät. (various references)

Greek		υποβρύχιο ραντάρ. (various references)

Hungarian		hanglokátor, szonár. (various references)

Italian		sonar. (various references)

Japanese Kanji		パチンコ台 (glassed-over arcade, pachinkomachine, pack, package, package media, package program, package tour, packaging, Packard, packing, pad, paddle, paddling, paddock, Panama, Panamax, Panasert hole, panavision, pap, passage, passenger, passing, passion, passionate, passive, passive smoking, passive solar house, passive sonar, pat, patch, patch test, patchwork, pate, patent, pathos, patio, patriotism, patrol, patrol car, patron, patting, priest, puck, putt, putting, putting green, putty, rotating warning light similar to the one on a "patokaa."), アクチニウ� 系列 (acrylic, Actinides, actinium series, activation, active, active defense, active homing, active solar house, active sonar, active sportswear, activity, actress, actual, actual time, actuality, orgasm). (various references)

Japanese Katakana		パッシブソナー (passive sonar), アクティブソナー (active sonar). (various references)

Korean		수중 음파 탐지기. (various references)

Pig Latin		onarsay

Portuguese		sonar. (various references)

Russian		сонар. (various references)

Serbo-Croatian		sonar. (various references)

Spanish		sonar (blare, blow, chink, clang, jangle, play, rattle, resound, ring, skirl, sound, speak, tintinnabulation, toot). (various references)

Swedish		ekolod (asdic, echo sounder), asdic. (various references)

Thai		ระบบหาวัตถุใต้น้ำ�"้วยคลื่นเสียง. (various references)

Turkish		sonar, deniz radarı. (various references)

Ukrainian		сонар, гідролокатор. (various references)
Source: compiled by the editor from various translation references.

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Derivations & Misspellings: Sonar

Derivations
	Words beginning with "sonar": sonarman, sonarmen, sonars. (additional references)
Misspellings
	"Sonar" is suggested in spellcheckers for the following: bonar, Conair, Donar, konar, Monaru, onar, ponar, sangar, senir, Sennar, shofar, Slokar, slonar, snarf, snarg, snoa, soan, soane, sodar, sofar, Sogna, somar, sona, sonac, sonae, sonare, sonax, sondar, soner, sonid, sonir, sonma, sonner, sonor, sonore, sonr, sonum, soran, sowar, sumar, Sunair, sunnr, sunr, Zohar, zoner. (additional references)
Source: compiled by the editor, based on several corpora (additional references).

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Anagrams: Sonar

Scrabble® Enable2K-Verified Anagrams
	Direct Anagrams: arson, roans.
	Words within the letters "a-n-o-r-s"
	-1 letter: naos, oars, osar, roan, soar, sora, sorn.
	-2 letters: ars, nor, nos, oar, ons, ora, ors, ran, ras, son.
	-3 letters: an, ar, as, na, no, on, or, os, so.
	Words containing the letters "a-n-o-r-s"
	+1 letter: acorns, adorns, aprons, argons, arseno, arsino, arsons, barons, groans, lorans, manors, narcos, norias, orangs, organs, parson, racons, radons, ramson, ransom, rayons, reason, romans, rowans, sarong, senora, shoran, sonars, sovran, tronas.
	+2 letters: anchors, angoras, anoraks, anurous, archons, arenose, arenous, aroints, aroynts, atoners, attorns, barongs, baryons, boranes, brogans, candors, cantors, carbons, cartons, coarsen, contras, corbans, corneas, coronas, cratons, crayons, dragons, enamors, erasion, garcons, garrons, hadrons, hoarsen, inroads, insofar, jargons, jordans, korunas, ladrons, lardons, loaners, macrons, maroons, marrons, masonry, matrons, moaners, morgans, narcose, narrows, natrons, nonarts, nonwars, normals, oarsman, oarsmen, onagers, onwards, oranges, ordains, origans, orphans, ourangs, pardons, parsons, partons, patrons, pawnors, persona, prolans, racoons, ramsons, ranchos, rancors, randoms, ransoms, rations, ratoons, rattons, reasons, reloans, robands, rodsman, romanos, ryokans, sadiron, saffron, santour, sarongs, saxhorn, senator, senhora, senoras, serrano, shorans, signora, soaring, soprani, soprano, sovrans, sporran, tarpons, transom, treason, uranous, warison.
Source: compiled by the editor from various references; see credits. SCRABBLE® is a registered trademark. All intellectual property rights in and to the game are owned in the U.S.A and Canada by Hasbro Inc., and throughout the rest of the world by J.W. Spear & Sons Limited of Maidenhead, Berkshire, England, a subsidiary of Mattel Inc. Mattel and Spear are not affiliated with Hasbro.