SonarAcoustic sensing methodFrench F70 type frigates (here, La Motte-Picquet) are fitted with variable depth sonar (VDS) type DUBV43 or DUBV43C towed sonars.A sonar image of the Soviet Navy minesweeper T-297, formerly the Latvian Virsaitis, which was shipwrecked in December 1941 in the Gulf of Finland.Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances (ranging), communicate with or detect objects on or under the surface of the water, such as other vessels.
BeamformingBeamforming or spatial filtering is a signal processing technique used in sensor arrays for directional signal transmission or reception. This is achieved by combining elements in an antenna array in such a way that signals at particular angles experience constructive interference while others experience destructive interference. Beamforming can be used at both the transmitting and receiving ends in order to achieve spatial selectivity.
Depth soundingDepth sounding, often simply called sounding, is measuring the depth of a body of water. Data taken from soundings are used in bathymetry to make maps of the floor of a body of water, such as the seabed topography. Soundings were traditionally shown on nautical charts in fathoms and feet. The National Oceanic and Atmospheric Administration (NOAA), the agency responsible for bathymetric data in the United States, still uses fathoms and feet on nautical charts.
SwatheA swathe ( British English, rhymes with "bathe"; or swath American English, rhymes with "cloth") is the strip of cut crop made by a scythe or a mowing-machine. A mower with a scythe cuts a swathe along the mowing-edge leaving the uncut grass to the right and the cut grass laid in a windrow to the left on the previously mown land. The swathe width depends on the blade length, the nature of the crop, and the mower, but for grass is usually about 1.5 metres (4.9 ft) wide.
BathymetryBathymetry (/bəˈθɪmətɹi/) is the study of underwater depth of ocean floors (seabed topography), river floors, or lake floors; the underwater equivalent to hypsometry or topography. The first recorded evidence of water depth measurements are from Ancient Egypt over 3000 years ago.
Echo soundingEcho sounding or depth sounding is the use of sonar for ranging, normally to determine the depth of water (bathymetry). It involves transmitting acoustic waves into water and recording the time interval between emission and return of a pulse; the resulting time of flight, along with knowledge of the speed of sound in water, allows determining the distance between sonar and target.
United States NavyMaritime service branch of the U.S. militaryMilitary unitThe United States Navy (USN) is the maritimeservice branch of the United States Armed Forces and is designated as the navy of the United States in the Constitution. With 290 combat vessels, it is the world's second largest navy, behind the People's Liberation Army Navy, and by far the largest by displacement, at 4.5 million tons in 2021.
Lockheed U-2The Lockheed U-2, nicknamed the "Dragon Lady", is an American single-engine, high–altitude reconnaissance aircraft operated by the United States Air Force (USAF) and the Central Intelligence Agency (CIA) since the 1950s. Designed for all-weather, day-and-night intelligence gathering at altitudes above 70,000 feet (21,300 meters), the U-2 has played a pivotal role in aerial surveillance for decades. Lockheed Corporation originally proposed the aircraft in 1953.
Acoustic waveType of energy propagation Acoustic waves are types of mechanical waves that propagate through matter—such as gas, liquid, and/or solids—by causing the particles of the medium to displace from their equilibrium positions. These waves carry energy and are characterized by properties like acoustic pressure, particle velocity, and acoustic intensity.Francis Gary PowersFrancis Gary Powers (August 17, 1929 – August 1, 1977) was an American pilot who served as a United States Air Force officer and a CIA employee. Powers is best known for his involvement in the 1960 U-2 incident, when he was shot down while flying a secret CIA spying mission over the Soviet Union. Powers survived, but was captured and sentenced to 10 years in a Soviet prison for espionage. He served 21 months of his sentence before being released in a prisoner swap in 1962.
TransceiverIn radio communication, a transceiver is an electronic device which is a combination of a radio transmitter and a receiver, hence the name. It can both transmit and receive radio waves using an antenna, for communication purposes. These two related functions are often combined in a single device to reduce manufacturing costs.
Time of flightTime of flight (ToF) is the measurement of the time taken by an object, particle or wave (be it acoustic, electromagnetic, etc.) to travel a distance through a medium. This information can then be used to measure velocity or path length, or as a way to learn about the particle or medium's properties (such as composition or flow rate).*As an Amazon Associate I earn from qualifying purchases.