224 relations: Absolute threshold, Absorption (acoustics), Acoustic Doppler current profiler, Acoustic location, Acoustic mine, Acoustic seabed classification, Acoustic tag, Acoustic torpedo, Acronym, Albert Beaumont Wood, Alexander Behm, Alperm, Alternating current, Ambient noise level, Ammonium dihydrogen phosphate, AN/AQS-20A, AN/SLQ-25 Nixie, AN/SQQ-32 Mine-hunting sonar, Analog signal, Anechoic tile, Animal echolocation, AQS-13, Array gain, Axis powers, Baffles (submarine), Baleen whale, Barium titanate, Bat, Bathymetry, Beaked whale, Beamforming, Bearing (navigation), Bistatic sonar, Blue whale, Board of Invention and Research, Boat, Bold (decoy), British H-class submarine, Bulk modulus, Carbon microphone, Casa Loma, Cast iron, Castor oil, Cavitation, Cetacean stranding, Chirp, Clearance diver, Code name, Computer, Continuous spectrum, ..., Convection, Database, Deep sea, Density, Depth charge, Digital data, Diver Detection Sonar, Dolphin, Doppler effect, Echo, Echo sounding, Eddy current, Effervescence, Electric battery, Electric generator, Electrostatics, Empirical evidence, Ferrite (magnet), Fessenden oscillator, Figure of merit, Fisheries acoustics, Fishfinder, Fishing, Fitness (biology), Flotilla, Fourier transform, Freight transport, French Third Republic, Frequency, Fresh water, Frogman, Fuel cell, Galfenol, GLORIA sidescan sonar, Gordon Eugene Martin, Grand Banks of Newfoundland, Haptic technology, Hedgehog (weapon), Hertz, High tech, Hull (watercraft), Hydroacoustics, Hydrophone, Infographic, Infrasound, Integrated Undersea Surveillance System insignia, Intellectual Property Office (United Kingdom), Inverse-square law, Isle of Portland, Japan, Lead zirconate titanate, Leonardo da Vinci, Lewis Fry Richardson, Lighthouse, Limpet mine, Long baseline acoustic positioning system, Long-Term Mine Reconnaissance System, Magnetostriction, Marine mammal, Mark 37 torpedo, Mark 60 CAPTOR, Mass, Metglas, Minesweeper, Mobile submarine simulator, Montreal, Morse code, Multibeam echosounder, Naval mine, Naval warfare, Navigation, Nazi Germany, Newfoundland (island), Noise (electronics), Nuclear reactor, Nuclear submarine, Ocean acoustic tomography, Office of Naval Intelligence, Ogg, Order of magnitude, Oxford English Dictionary, Oyashio-class submarine, Parametric array, Passive acoustics, Passive radar, Patent, Paul Langevin, Piezoelectricity, Plan position indicator, Potassium sodium tartrate, Pressure, Prestressed concrete, Proceedings of the Royal Society, Project Artemis, Propagation loss, Propeller, Pulse (signal processing), Pulse compression, Quartz, Radar, Rare-earth element, Reflection (physics), Reflection seismology, Refraction, Reginald Fessenden, Remotely operated underwater vehicle, Reverberation, RMS Titanic, RNAS Portland (HMS Osprey), Robert William Boyle, Royal Navy, Salinity, Scattering, Scientific echosounder, Scuba diving, Seawater, Ship, Shoaling and schooling, Side-scan sonar, Snell's law, SODAR, SOFAR channel, Sonar 2087, Sonar signal processing, Sonobuoy, SOSUS, Sound, Southern California Bight, Soviet Union, Spectral density, Spectrogram, Speed of sound, Sphere, Squid (weapon), SSTD, Submarine, Submarine navigation, Sustainability, Swiftsure-class submarine, Swim bladder, Synthetic aperture sonar, Target strength, Terfenol-D, Thales Underwater Systems, The World's Work, Thermocline, Time (magazine), Titan (moon), Tizard Mission, Tonpilz, Toronto, Toshiba, Towed array sonar, Trajectory, Transducer, Transformer, U.S. National Geodetic Survey, Ultrasonic transducer, Ultrasound, Underwater acoustics, Underwater Port Security System, United Kingdom of Great Britain and Ireland, United States, Upward looking sonar, USS Abbot (DD-629), Vanguard-class submarine, Vibration, Visibility, Wake homing, Wave, Whale, World War I, World War II, Wrench. Expand index (174 more) » « Shrink index
In neuroscience and psychophysics, an absolute threshold was originally defined as the lowest level of a stimulus – light, sound, touch, etc.
Acoustic absorption refers to the process by which a material, structure, or object takes in sound energy when sound waves are encountered, as opposed to reflecting the energy.
An acoustic Doppler current profiler (ADCP) is a hydroacoustic current meter similar to a sonar, used to measure water current velocities over a depth range using the Doppler effect of sound waves scattered back from particles within the water column.
Acoustic location is the use of sound to determine the distance and direction of its source or reflector.
An acoustic mine is a type of naval mine which monitors audio activity in its vicinity.
Acoustic seabed classification is the partitioning of a seabed acoustic image into discrete physical entities or classes.
Acoustic tags are small sound-emitting devices that allow the detection and/or remote tracking of fish in three dimensions for fisheries research.
An acoustic torpedo is a torpedo that aims itself by listening for characteristic sounds of its target or by searching for it using sonar (acoustic homing).
An acronym is a word or name formed as an abbreviation from the initial components in a phrase or a word, usually individual letters (as in NATO or laser) and sometimes syllables (as in Benelux).
Albert Beaumont Wood DSc (1890 – 19 July 1964), better known as A B Wood, was a British physicist, known for his pioneering work in the field of underwater acoustics and sonar.
Alexander Behm (11 November 1880 in Sternberg (Mecklenburg) – 22 January 1952 in Tarp (Schleswig-Flensburg)) was a German physicist who developed working ocean echo sounder in Germany at the same time Reginald Fessenden was doing so in North America.
Alperm (also alfenol or alfer) is a class of alloys comprising 83-90% of iron and 10-17% of aluminium.
Alternating current (AC) is an electric current which periodically reverses direction, in contrast to direct current (DC) which flows only in one direction.
In atmospheric sounding and noise pollution, ambient noise level (sometimes called background noise level, reference sound level, or room noise level) is the background sound pressure level at a given location, normally specified as a reference level to study a new intrusive sound source.
Ammonium dihydrogen phosphate (ADP), also and better known as monoammonium phosphate (MAP) in order not to confuse it with adenosine diphosphate (ADP), with formula NH4H2PO4, is formed when a solution of phosphoric acid is added to ammonia until the solution is distinctly acidic.
The AQS-20A is a sonar mine countermeasure detection system, developed by Raytheon.
The AN/SLQ-25 Nixie and its variants are towed torpedo decoys used on US and allied warships.
The AN/SQQ-32 Minehunting Sonar Set (MSS) is a variable-depth mine-hunting sonar system originally developed by Raytheon and Thales Underwater Systems (formerly Thomson Marconi Sonar) for the United States Navy.
An analog signal is any continuous signal for which the time varying feature (variable) of the signal is a representation of some other time varying quantity, i.e., analogous to another time varying signal.
Anechoic tiles are rubber or synthetic polymer tiles containing thousands of tiny voids, applied to the outer hulls of military ships and submarines, as well as anechoic chambers.
Echolocation, also called bio sonar, is the biological sonar used by several kinds of animals.
The AQS-13 (AN/AQS-13) series sonars, AQS-13, AQS-13A, AQS-13B, AQS-13E and AQS-13F served as the helicopter dipping sonar systems for the United States Navy.
In MIMO communication systems, array gain means a power gain of transmitted signals that is achieved by using multiple-antennas at transmitter and/or receiver, with respect to single-input single-output case.
The Axis powers (Achsenmächte; Potenze dell'Asse; 枢軸国 Sūjikukoku), also known as the Axis and the Rome–Berlin–Tokyo Axis, were the nations that fought in World War II against the Allied forces.
The baffles is the area in the water directly behind a submarine or ship through which a hull-mounted sonar cannot hear.
Baleen whales (systematic name Mysticeti), known earlier as whalebone whales, form a parvorder of the infraorder Cetacea (whales, dolphins and porpoises).
Barium titanate is the inorganic compound with the chemical formula BaTiO3.
Bats are mammals of the order Chiroptera; with their forelimbs adapted as wings, they are the only mammals naturally capable of true and sustained flight.
Bathymetry is the study of underwater depth of lake or ocean floors.
Beaked whales are the members of the family Ziphiidae, which consists of 23 species.
Beamforming or spatial filtering is a signal processing technique used in sensor arrays for directional signal transmission or reception.
In navigation bearing may refer, depending on the context, to any of: (A) the direction or course of motion itself; (B) the direction of a distant object relative to the current course (or the "change" in course that would be needed to get to that distant object); or (C), the angle away from North of a distant point as observed at the current point.
Most sonar systems are monostatic, in that the transmitter and receiver are in the same place.
The blue whale (Balaenoptera musculus) is a marine mammal belonging to the baleen whale parvorder, Mysticeti.
The Board of Invention and Research (BIR) was a British expert-level committee, initiated by the Admiralty of the Royal Navy.
A boat is a watercraft of a large range of type and size.
Bold (a term derived from kobold) was a German sonar decoy, used by U-boats during the Second World War from 1942 onwards.
The bulk modulus (K or B) of a substance is a measure of how resistant to compressibility that substance is.
The carbon microphone, also known as carbon button microphone, button microphone, or carbon transmitter, is a type of microphone, a transducer that converts sound to an electrical audio signal.
Casa Loma (Spanish for "Hill House") is a Gothic Revival style mansion and garden in midtown Toronto, Ontario, Canada, that is now a historic house museum and landmark.
Cast iron is a group of iron-carbon alloys with a carbon content greater than 2%.
Castor oil is a vegetable oil obtained by pressing the seeds of the castor oil plant (Ricinus communis).
Cavitation is the formation of vapour cavities in a liquid, small liquid-free zones ("bubbles" or "voids"), that are the consequence of forces acting upon the liquid.
Cetacean stranding, commonly known as beaching, is a phenomenon in which whales and dolphins strand themselves on land, usually on a beach.
A chirp is a signal in which the frequency increases (up-chirp) or decreases (down-chirp) with time.
A clearance diver was originally a specialist naval diver who used explosives underwater to remove obstructions to make harbours and shipping channels safe to navigate, but later the term "clearance diver" was used to include other naval underwater work.
A code name or cryptonym is a word or name used, sometimes clandestinely, to refer to another name, word, project or person.
A computer is a device that can be instructed to carry out sequences of arithmetic or logical operations automatically via computer programming.
In physics, a continuous spectrum usually means a set of attainable values for some physical quantity (such as energy or wavelength) that is best described as an interval of real numbers, as opposed to a discrete spectrum, a set of attainable values that is discrete in the mathematical sense, where there is a positive gap between each value and the next one.
Convection is the heat transfer due to bulk movement of molecules within fluids such as gases and liquids, including molten rock (rheid).
A database is an organized collection of data, stored and accessed electronically.
The deep sea or deep layer is the lowest layer in the ocean, existing below the thermocline and above the seabed, at a depth of 1000 fathoms (1800 m) or more.
The density, or more precisely, the volumetric mass density, of a substance is its mass per unit volume.
A depth charge is an anti-submarine warfare weapon.
Digital data, in information theory and information systems, is the discrete, discontinuous representation of information or works.
Diver Detection Sonar (DDS) systems are sonar and acoustic location systems employed underwater for the detection of divers and submerged swimmer delivery vehicles (SDVs).
Dolphins are a widely distributed and diverse group of aquatic mammals.
The Doppler effect (or the Doppler shift) is the change in frequency or wavelength of a wave in relation to observer who is moving relative to the wave source.
In audio signal processing and acoustics, Echo is a reflection of sound that arrives at the listener with a delay after the direct sound.
Echo sounding is a type of sonar used to determine the depth of water by transmitting sound pulses into water.
Eddy currents (also called Foucault currents) are loops of electrical current induced within conductors by a changing magnetic field in the conductor due to Faraday's law of induction.
Effervescence is the escape of gas from an aqueous solution and the foaming or fizzing that results from that release.
An electric battery is a device consisting of one or more electrochemical cells with external connections provided to power electrical devices such as flashlights, smartphones, and electric cars.
In electricity generation, a generator is a device that converts motive power (mechanical energy) into electrical power for use in an external circuit.
Electrostatics is a branch of physics that studies electric charges at rest.
Empirical evidence, also known as sensory experience, is the information received by means of the senses, particularly by observation and documentation of patterns and behavior through experimentation.
A ferrite is a ceramic material made by mixing and firing large proportions iron(III) oxide (Fe2O3, rust) blended with small proportions of one or more additional metallic elements, such as barium, manganese, nickel, and zinc.
A Fessenden oscillator is an electro-acoustic transducer invented by Reginald Fessenden, with development starting in 1912 at the Submarine Signal Company of Boston.
A figure of merit is a quantity used to characterize the performance of a device, system or method, relative to its alternatives.
Fisheries acoustics includes a range of research and practical application topics using acoustical devices as sensors in aquatic environments.
A fishfinder or sounder (Australia) is an instrument used to locate fish underwater by detecting reflected pulses of sound energy, as in sonar.
Fishing is the activity of trying to catch fish.
Fitness (often denoted w or ω in population genetics models) is the quantitative representation of natural and sexual selection within evolutionary biology.
A flotilla (from Spanish, meaning a small flota (fleet) of ships, and this from French flotte, and this from Russian "флот" (flot), meaning "fleet"), or naval flotilla, is a formation of small warships that may be part of a larger fleet.
The Fourier transform (FT) decomposes a function of time (a signal) into the frequencies that make it up, in a way similar to how a musical chord can be expressed as the frequencies (or pitches) of its constituent notes.
Freight transport is the physical process of transporting commodities and merchandise goods and cargo.
The French Third Republic (La Troisième République, sometimes written as La IIIe République) was the system of government adopted in France from 1870 when the Second French Empire collapsed during the Franco-Prussian War until 1940 when France's defeat by Nazi Germany in World War II led to the formation of the Vichy government in France.
Frequency is the number of occurrences of a repeating event per unit of time.
Fresh water (or freshwater) is any naturally occurring water except seawater and brackish water.
A frogman is someone who is trained in scuba diving or swimming underwater in a tactical capacity that includes police or military work.
A fuel cell is an electrochemical cell that converts the chemical energy from a fuel into electricity through an electrochemical reaction of hydrogen fuel with oxygen or another oxidizing agent.
In materials science, galfenol is the general term for an alloy of iron and gallium.
The GLORIA sidescan sonar is a side-scan sonar system for determining the topography of the ocean floor.
Gordon Eugene Martin is a physicist and author in the field of piezoelectric materials for underwater sound transducers.
The Grand Banks of Newfoundland are a group of underwater plateaus south-east of Newfoundland on the North American continental shelf.
Haptic or kinesthetic communication recreates the sense of touch by applying forces, vibrations, or motions to the user.
The Hedgehog (also known as an Anti-Submarine Projector) was a forward-throwing anti-submarine weapon that was used during the Battle of the Atlantic in the Second World War.
The hertz (symbol: Hz) is the derived unit of frequency in the International System of Units (SI) and is defined as one cycle per second.
High technology, often abbreviated to high tech (adjective forms high-technology, high-tech or hi-tech) is technology that is at the cutting edge: the most advanced technology available.
The hull is the watertight body of a ship or boat.
Hydroacoustics is the study and application of sound in water.
A hydrophone (Ancient Greek ὕδωρ.
Infographics (a clipped compound of "information" and "graphics") are graphic visual representations of information, data or knowledge intended to present information quickly and clearly.
Infrasound, sometimes referred to as low-frequency sound, is sound that is lower in frequency than 20 Hz or cycles per second, the "normal" limit of human hearing.
The Integrated Undersea Surveillance System breast insignia is a military badge of the United States Navy which was officially created by OPNAVINST 1020.5 on 24 December 1990.
The Intellectual Property Office of the United Kingdom (often The IPO) is, since 2 April 2007, the operating name of The Patent Office.
The inverse-square law, in physics, is any physical law stating that a specified physical quantity or intensity is inversely proportional to the square of the distance from the source of that physical quantity.
The Isle of Portland is a limestone tied island, long by wide, in the English Channel.
Japan (日本; Nippon or Nihon; formally 日本国 or Nihon-koku, lit. "State of Japan") is a sovereign island country in East Asia.
Lead zirconate titanate is an inorganic compound with the chemical formula Pb (0≤x≤1).
Leonardo di ser Piero da Vinci (15 April 14522 May 1519), more commonly Leonardo da Vinci or simply Leonardo, was an Italian polymath of the Renaissance, whose areas of interest included invention, painting, sculpting, architecture, science, music, mathematics, engineering, literature, anatomy, geology, astronomy, botany, writing, history, and cartography.
Lewis Fry Richardson, FRS (11 October 1881 – 30 September 1953) was an English mathematician, physicist, meteorologist, psychologist and pacifist who pioneered modern mathematical techniques of weather forecasting, and the application of similar techniques to studying the causes of wars and how to prevent them.
A lighthouse is a tower, building, or other type of structure designed to emit light from a system of lamps and lenses and to serve as a navigational aid for maritime pilots at sea or on inland waterways.
A limpet mine is a type of naval mine attached to a target by magnets.
A long baseline (LBL) acoustic positioning system is one of three broad classes of underwater acoustic positioning systems that are used to track underwater vehicles and divers.
The AN/BLQ-11 autonomous unmanned undersea vehicle (formerly the Long-Term Mine Reconnaissance System (LMRS)) is a torpedo tube-launched and tube-recovered underwater search and survey unmanned undersea vehicle (UUV) capable of performing autonomous minefield reconnaissance as much as in advance of a host -, -, or -class submarine. LMRS is equipped with both forward-looking sonar and side-scan synthetic aperture sonar. Boeing concluded the detailed design phase of the development project on 31 August 1999. In January 2006, successfully demonstrated homing and docking of an LMRS UUV system during at-sea testing.
Magnetostriction (cf. electrostriction) is a property of ferromagnetic materials that causes them to change their shape or dimensions during the process of magnetization.
Marine mammals are aquatic mammals that rely on the ocean and other marine ecosystems for their existence.
The Mark 37 torpedo is a torpedo with electrical propulsion, developed for the US Navy after World War II.
The Mark 60 CAPTOR (Encapsulated Torpedo) is the United States' only deep-water anti-submarine naval mine.
Mass is both a property of a physical body and a measure of its resistance to acceleration (a change in its state of motion) when a net force is applied.
Metglas is a thin amorphous metal alloy ribbon produced by using rapid solidification process of approximately.
A minesweeper is a small naval warship designed to engage in minesweeping.
The mobile submarine simulator (MOSS) MK70 is a sonar decoy used by submarines of the United States Navy.
Montreal (officially Montréal) is the most populous municipality in the Canadian province of Quebec and the second-most populous municipality in Canada.
Morse code is a method of transmitting text information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment.
A multibeam echosounder is a type of sonar that is used to map the seabed.
A naval mine is a self-contained explosive device placed in water to damage or destroy surface ships or submarines.
Naval warfare is combat in and on the sea, the ocean, or any other battlespace involving major body of water such as a large lake or wide river.
Navigation is a field of study that focuses on the process of monitoring and controlling the movement of a craft or vehicle from one place to another.
Nazi Germany is the common English name for the period in German history from 1933 to 1945, when Germany was under the dictatorship of Adolf Hitler through the Nazi Party (NSDAP).
Newfoundland (Terre-Neuve) is a large Canadian island off the east coast of the North American mainland, and the most populous part of the Canadian province of Newfoundland and Labrador.
In electronics, noise is an unwanted disturbance in an electrical signal.
A nuclear reactor, formerly known as an atomic pile, is a device used to initiate and control a self-sustained nuclear chain reaction.
A nuclear submarine is a submarine powered by a nuclear reactor.
Ocean acoustic tomography is a technique used to measure temperatures and currents over large regions of the ocean.
The Office of Naval Intelligence (ONI) is the military intelligence agency of the United States Navy.
Ogg is a free, open container format maintained by the Xiph.Org Foundation.
An order of magnitude is an approximate measure of the number of digits that a number has in the commonly-used base-ten number system.
The Oxford English Dictionary (OED) is the main historical dictionary of the English language, published by the Oxford University Press.
The Oyashio class is a series of Japanese diesel-electric attack submarines operated by the JMSDF. The submarines entered service in the late 1990s. The submarines are larger than the earlier, to provide space for a flank sonar array.
A parametric array, in the field of acoustics, is a nonlinear transduction mechanism that generates narrow, nearly side lobe-free beams of low frequency sound, through the mixing and interaction of high frequency sound waves, effectively overcoming the diffraction limit (a kind of spatial 'uncertainty principle') associated with linear acoustics.
Passive acoustics is the action of listening for sounds(Joe-Said), often at specific frequencies or for purposes of specific analyses.
Passive radar systems (also referred to as passive coherent location and passive covert radar) encompass a class of radar systems that detect and track objects by processing reflections from non-cooperative sources of illumination in the environment, such as commercial broadcast and communications signals.
A patent is a set of exclusive rights granted by a sovereign state or intergovernmental organization to an inventor or assignee for a limited period of time in exchange for detailed public disclosure of an invention.
Paul Langevin (23 January 1872 – 19 December 1946) was a prominent French physicist who developed Langevin dynamics and the Langevin equation.
Piezoelectricity is the electric charge that accumulates in certain solid materials (such as crystals, certain ceramics, and biological matter such as bone, DNA and various proteins) in response to applied mechanical stress.
The plan position indicator (PPI), is the most common type of radar display.
Potassium sodium tartrate tetrahydrate, also known as Rochelle salt, is a double salt of tartaric acid first prepared (in about 1675) by an apothecary, Pierre Seignette, of La Rochelle, France.
Pressure (symbol: p or P) is the force applied perpendicular to the surface of an object per unit area over which that force is distributed.
Prestressed concrete is a form of concrete used in construction which is "pre-stressed" by being placed under compression prior to supporting any loads beyond its own dead weight.
Proceedings of the Royal Society is the parent title of two scientific journals published by the Royal Society.
Project Artemis was a project undertaken by the United States Navy in the 1960s, which produced a low-frequency active sonar system that could detect submarines at long range.
In underwater acoustics, propagation loss is a measure of the reduction in sound intensity as the sound propagates away from an underwater sound source.
A propeller is a type of fan that transmits power by converting rotational motion into thrust.
A pulse in signal processing is a rapid, transient change in the amplitude of a signal from a baseline value to a higher or lower value, followed by a rapid return to the baseline value.
Pulse compression is a signal processing technique commonly used by radar, sonar and echography to increase the range resolution as well as the signal to noise ratio.
Quartz is a mineral composed of silicon and oxygen atoms in a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO2.
Radar is an object-detection system that uses radio waves to determine the range, angle, or velocity of objects.
A rare-earth element (REE) or rare-earth metal (REM), as defined by IUPAC, is one of a set of seventeen chemical elements in the periodic table, specifically the fifteen lanthanides, as well as scandium and yttrium.
Reflection is the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated.
Reflection seismology (or seismic reflection) is a method of exploration geophysics that uses the principles of seismology to estimate the properties of the Earth's subsurface from reflected seismic waves.
Refraction is the change in direction of wave propagation due to a change in its transmission medium.
Reginald Aubrey Fessenden (October 6, 1866 – July 22, 1932) was a Canadian-born inventor, who did a majority of his work in the United States and also claimed U.S. citizenship through his American-born father.
A remotely operated underwater vehicle (ROV) is a tethered underwater mobile device.
Reverberation, in psychoacoustics and acoustics, is a persistence of sound after the sound is produced.
RMS Titanic was a British passenger liner that sank in the North Atlantic Ocean in the early hours of 15 April 1912, after colliding with an iceberg during its maiden voyage from Southampton to New York City.
RNAS Portland (ICAO: EGDP) was an air station of the Royal Navy, situated at the Isle of Portland, Dorset, England.
Robert William Boyle (October 2, 1883 – April 18, 1955) was a physicist and one of the most important early pioneers in the development of sonar.
The Royal Navy (RN) is the United Kingdom's naval warfare force.
Salinity is the saltiness or amount of salt dissolved in a body of water (see also soil salinity).
Scattering is a general physical process where some forms of radiation, such as light, sound, or moving particles, are forced to deviate from a straight trajectory by one or more paths due to localized non-uniformities in the medium through which they pass.
A scientific echosounder is a device which uses sonar technology for the measurement of underwater physical and biological components—this device is also known as scientific sonar.
Scuba diving is a mode of underwater diving where the diver uses a self-contained underwater breathing apparatus (scuba) which is completely independent of surface supply, to breathe underwater.
Seawater, or salt water, is water from a sea or ocean.
A ship is a large watercraft that travels the world's oceans and other sufficiently deep waterways, carrying passengers or goods, or in support of specialized missions, such as defense, research and fishing.
In biology, any group of fish that stay together for social reasons are shoaling (pronounced), and if the group is swimming in the same direction in a coordinated manner, they are schooling (pronounced). In common usage, the terms are sometimes used rather loosely.
Side-scan sonar (also sometimes called side scan sonar, sidescan sonar, side imaging sonar, side-imaging sonar and bottom classification sonar) is a category of sonar system that is used to efficiently create an image of large areas of the sea floor.
Snell's law (also known as Snell–Descartes law and the law of refraction) is a formula used to describe the relationship between the angles of incidence and refraction, when referring to light or other waves passing through a boundary between two different isotropic media, such as water, glass, or air.
SODAR (SOnic Detection And Ranging), also written as sodar, is a meteorological instrument used as a wind profiler to measure the scattering of sound waves by atmospheric turbulence.
Sound speed as a function of depth at a position north of Hawaii in the Pacific Ocean derived from the 2005 World Ocean Atlas. The SOFAR channel axis is at ca. 750-m depth The SOFAR channel (short for Sound Fixing and Ranging channel), or deep sound channel (DSC), is a horizontal layer of water in the ocean at which depth the speed of sound is at its minimum.
Sonar 2087 is a towed array sonar designed and manufactured by Thales Underwater Systems at sites in the UK (Cheadle Heath in Stockport and Templecombe in Somerset) and in France (Brest).
Sonar systems are generally used underwater for range finding and detection.
A sonobuoy (a portmanteau of sonar and buoy) is a relatively small buoy (typically, in diameter and long) expendable sonar system that is dropped/ejected from aircraft or ships conducting anti-submarine warfare or underwater acoustic research.
SOSUS, an acronym for sound surveillance system, is a chain of underwater listening posts located around the world in places such as the Atlantic Ocean near Greenland, Iceland and the United Kingdom—the GIUK gap—and at various locations in the Pacific Ocean.
In physics, sound is a vibration that typically propagates as an audible wave of pressure, through a transmission medium such as a gas, liquid or solid.
The Southern California Bight is the curved coastline of Southern California from Point Conception to San Diego.
The Soviet Union, officially the Union of Soviet Socialist Republics (USSR) was a socialist state in Eurasia that existed from 1922 to 1991.
The power spectrum S_(f) of a time series x(t) describes the distribution of power into frequency components composing that signal.
A spectrogram is a visual representation of the spectrum of frequencies of sound or other signal as they vary with time.
The speed of sound is the distance travelled per unit time by a sound wave as it propagates through an elastic medium.
A sphere (from Greek σφαῖρα — sphaira, "globe, ball") is a perfectly round geometrical object in three-dimensional space that is the surface of a completely round ball (viz., analogous to the circular objects in two dimensions, where a "circle" circumscribes its "disk").
Squid was a British World War II ship-mounted anti-submarine weapon.
The United Kingdom Surface Ship Torpedo Defence (SSTD) system entered into service with the Royal Navy in 2004.
A submarine (or simply sub) is a watercraft capable of independent operation underwater.
Submarine navigation underwater requires special skills and technologies not needed by surface ships.
Sustainability is the process of change, in which the exploitation of resources, the direction of investments, the orientation of technological development and institutional change are all in harmony and enhance both current and future potential to meet human needs and aspirations.
The Swiftsure class was a class of nuclear-powered fleet submarines in service with the Royal Navy from the early 1970s until 2010.
The swim bladder, gas bladder, fish maw or air bladder is an internal gas-filled organ that contributes to the ability of many bony fish (but not cartilaginous fish) to control their buoyancy, and thus to stay at their current water depth without having to waste energy in swimming.
Synthetic aperture sonar (SAS) is a form of sonar in which sophisticated post-processing of sonar data are used in ways closely analogous to synthetic aperture radar.
The target strength or acoustic size is a measure of the reflection coefficient of a sonar target.
Terfenol-D, an alloy of the formula x1−x (x ~ 0.3), is a magnetostrictive material.
Thales Underwater Systems (TUS), formerly known as Thomson Marconi Sonar, is an international defence manufacturer specialising in sonar systems for submarines, surface warships, and aircraft as well as communications masts and systems for submarines.
The World's Work (1900–1932) was a monthly magazine that covered national affairs from a pro-business point of view.
A thermocline (also known as the thermal layer or the metalimnion in lakes) is a thin but distinct layer in a large body of fluid (e.g. water, such as an ocean or lake) or air (such as an atmosphere) in which temperature changes more rapidly with depth than it does in the layers above or below.
Time is an American weekly news magazine and news website published in New York City.
Titan is the largest moon of Saturn.
The Tizard Mission, officially the British Technical and Scientific Mission, was a British delegation that visited the United States during the Second World War in order to obtain the industrial resources to exploit the military potential of the research and development (R&D) work completed by the UK up to the beginning of World War II, but that Britain itself could not exploit due to the immediate requirements of war-related production.
The term tonpilz or "acoustic mushroom" may refer to a certain type of underwater electro-acoustic transducer.
Toronto is the capital city of the province of Ontario and the largest city in Canada by population, with 2,731,571 residents in 2016.
, commonly known as Toshiba, is a Japanese multinational conglomerate headquartered in Tokyo, Japan.
A towed array sonar is a system of hydrophones towed behind a submarine or a surface ship on a cable.
A trajectory or flight path is the path that a massive object in motion follows through space as a function of time.
A transducer is a device that converts energy from one form to another.
A transformer is a static electrical device that transfers electrical energy between two or more circuits through electromagnetic induction.
The National Geodetic Survey (NGS), formerly the United States Survey of the Coast (1807–1836), United States Coast Survey (1836–1878), and United States Coast and Geodetic Survey (USC&GS) (1878–1970), is a United States federal agency that defines and manages a national coordinate system, providing the foundation for transportation and communication; mapping and charting; and a large number of applications of science and engineering.
Ultrasonic transducers or ultrasonic sensors are a type of acoustic sensor divided into three broad categories: transmitters, receivers and transceivers.
Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing.
Underwater acoustics is the study of the propagation of sound in water and the interaction of the mechanical waves that constitute sound with the water and its boundaries.
Underwater Port Security System (UPSS) was developed for the United States Coast Guard and the Maritime Safety and Security Teams (MSSTs) as an anti-frogman technique.
The United Kingdom of Great Britain and Ireland was established by the Acts of Union 1800, which merged the kingdoms of Great Britain and Ireland.
The United States of America (USA), commonly known as the United States (U.S.) or America, is a federal republic composed of 50 states, a federal district, five major self-governing territories, and various possessions.
An upward looking sonar (ULS) is a sonar device pointed upwards looking towards the surface of the sea.
USS Abbot (DD-629) was a in the service of the United States Navy.
The Vanguard class is a class of nuclear-powered ballistic missile submarines (SSBNs) in service with the Royal Navy.
Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point.
In meteorology, visibility is a measure of the distance at which an object or light can be clearly discerned.
Wake homing is a technique used to guide torpedoes to their target.
In physics, a wave is a disturbance that transfers energy through matter or space, with little or no associated mass transport.
Whales are a widely distributed and diverse group of fully aquatic placental marine mammals.
World War I (often abbreviated as WWI or WW1), also known as the First World War, the Great War, or the War to End All Wars, was a global war originating in Europe that lasted from 28 July 1914 to 11 November 1918.
World War II (often abbreviated to WWII or WW2), also known as the Second World War, was a global war that lasted from 1939 to 1945, although conflicts reflecting the ideological clash between what would become the Allied and Axis blocs began earlier.
A wrench is a tool used to provide grip and mechanical advantage in applying torque to turn objects—usually rotary fasteners, such as nuts and bolts—or keep them from turning.
ASDIC, Acoustic radar, Active acoustics, Active sonar, Anti-Submarine Detection and Identification Commission, Asdic, Asdivite, Lfas, Low Frequency Active Sonar, Low frequency active sonar, Passive Sonar, Passive sonar, SONAR, So.n.a.r., Sonar Projector, Sonar system, Sonars, Sound navigation and ranging, Ultra-sonic, Variable Depth Sonar, Variable depth sonar.