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Underwater searches are procedures to find a known or suspected target object or objects in a specified search area under water. They may be carried out underwater by divers, manned submersibles, remotely operated underwater vehicles, or autonomous underwater vehicles, or from the surface by other agents, including surface vessels, aircraft and cadaver dogs. A search method attempts to provide full coverage of the search area. This is greatly influenced by the width of the sweep, which largely depends on the method used to detect the target. For divers in conditions of zero visibility, this is as far as the diver can feel with their hands while proceeding along the pattern. When visibility is better, it depends on the distance at which the target can be seen from the pattern, or detected by sonar or magnetic field anomalies. In all cases, the search pattern should completely cover the search area without excessive redundancy or missed areas. Overlap is needed to compensate for ina ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Submersibles
A submersible is a small watercraft designed to operate underwater. The term "submersible" is often used to differentiate from other underwater vessels known as submarines, in that a submarine is a fully self-sufficient craft, capable of independent cruising with its own power supply and air renewal system, whereas a submersible is usually supported by a nearby surface vessel, platform, shore team or sometimes a larger submarine. In common usage by the general public, however, the word "submarine" may be used to describe a craft that is by the technical definition actually a submersible. There are many types of submersibles, including both crewed and uncrewed craft, otherwise known as remotely operated vehicles (ROVs) or unmanned underwater vehicles (UUVs). Submersibles have many uses worldwide, such as oceanography, underwater archaeology, ocean exploration, adventure, equipment maintenance and recovery, and underwater videography. History The first underwater vessel was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scuba Diver
Scuba diving is a mode of underwater diving whereby divers use breathing equipment that is completely independent of a surface air supply. The name "scuba", an acronym for " Self-Contained Underwater Breathing Apparatus", was coined by Christian J. Lambertsen in a patent submitted in 1952. Scuba divers carry their own source of breathing gas, usually compressed air, affording them greater independence and movement than surface-supplied divers, and more time underwater than free divers. Although the use of compressed air is common, a gas blend with a higher oxygen content, known as enriched air or nitrox, has become popular due to the reduced nitrogen intake during long and/or repetitive dives. Also, breathing gas diluted with helium may be used to reduce the likelihood and effects of nitrogen narcosis during deeper dives. Open circuit scuba systems discharge the breathing gas into the environment as it is exhaled, and consist of one or more diving cylinders containing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sonobuoys
A sonobuoy (a portmanteau of sonar and buoy) is a relatively small buoy – typically diameter and long – expendable sonar system that is dropped/ejected from aircraft or ships conducting anti-submarine warfare or underwater acoustic research. Theory of operation Sonobuoys are ejected from aircraft in canisters and deploy upon water impact. An inflatable surface float with a radio transmitter remains on the surface for communication with the aircraft, while one or more hydrophone sensors and stabilizing equipment descend below the surface to a selected depth that is variable, depending on environmental conditions and the search pattern. The buoy relays acoustic information from its hydrophone(s) via UHF/VHF radio to operators on board the aircraft. History With the technological improvement of the submarine in modern warfare, the need for an effective tracking system was born. Sound Navigation And Ranging (SONAR) was originally developed by the British—who calle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unmanned Aerial Vehicle
An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controller and a system of communications with the UAV. The flight of UAVs may operate under remote control by a human operator, as remotely-piloted aircraft (RPA), or with various degrees of autonomy, such as autopilot assistance, up to fully autonomous aircraft that have no provision for human intervention. UAVs were originally developed through the twentieth century for military missions too "dull, dirty or dangerous" for humans, and by the twenty-first, they had become essential assets to most militaries. As control technologies improved and costs fell, their use expanded to many non-military applications.Hu, J.; Bhowmick, P.; Jang, I.; Arvin, F.; Lanzon, A.,A Decentralized Cluster Formation Containment Framework for Multirobot Systems IEEE ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines. Common examples of aircraft include airplanes, helicopters, airships (including blimps), gliders, paramotors, and hot air balloons. The human activity that surrounds aircraft is called ''aviation''. The science of aviation, including designing and building aircraft, is called '' aeronautics.'' Crewed aircraft are flown by an onboard pilot, but unmanned aerial vehicles may be remotely controlled or self-controlled by onboard computers. Aircraft may be classified by different criteria, such as lift type, aircraft propulsion, usage and others. History Flying model craft and stories of manned flight go back many centuries; however, the first manned ascent — and safe descent — in modern times took place by larger h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gyrocompass
A gyrocompass is a type of non-magnetic compass which is based on a fast-spinning disc and the rotation of the Earth (or another planetary body if used elsewhere in the universe) to find geographical direction automatically. The use of a gyrocompass is one of the seven fundamental ways to determine the heading of a vehicle. A gyroscope is an essential component of a gyrocompass, but they are different devices; a gyrocompass is built to use the effect of gyroscopic precession, which is a distinctive aspect of the general gyroscopic effect. Gyrocompasses are widely used for navigation on ships, because they have two significant advantages over magnetic compasses: * they find true north as determined by the axis of the Earth's rotation, which is different from, and navigationally more useful than, ''magnetic'' north, and * they are unaffected by ferromagnetic materials, such as in a ship's steel hull, which distort the magnetic field. Aircraft commonly use gyroscopic instrum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Side-scan Sonar
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. Uses Side-scan sonar may be used to conduct surveys for marine archaeology; in conjunction with seafloor samples it is able to provide an understanding of the differences in material and texture type of the seabed. Side-scan sonar imagery is also a commonly used tool to detect debris items and other obstructions on the seafloor that may be hazardous to shipping or to seafloor installations by the oil and gas industry. In addition, the status of pipelines and cables on the seafloor can be investigated using side-scan sonar. Side-scan data are frequently acquired along with bathymetric soundings and sub-bottom profiler data, thus providing a glimpse of the shallow structure of the seabed. Side-scan sonar is also used for fisherie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetometer
A magnetometer is a device that measures magnetic field or magnetic dipole moment. Different types of magnetometers measure the direction, strength, or relative change of a magnetic field at a particular location. A compass is one such device, one that measures the direction of an ambient magnetic field, in this case, the Earth's magnetic field. Other magnetometers measure the magnetic dipole moment of a magnetic material such as a ferromagnet, for example by recording the effect of this magnetic dipole on the induced current in a coil. The first magnetometer capable of measuring the absolute magnetic intensity at a point in space was invented by Carl Friedrich Gauss in 1833 and notable developments in the 19th century included the Hall effect, which is still widely used. Magnetometers are widely used for measuring the Earth's magnetic field, in geophysical surveys, to detect magnetic anomalies of various types, and to determine the dipole moment of magnetic materials. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Recreational
Recreation is an activity of leisure, leisure being discretionary time. The "need to do something for recreation" is an essential element of human biology and psychology. Recreational activities are often done for enjoyment, amusement, or pleasure and are considered to be " fun". Etymology The term ''recreation'' appears to have been used in English first in the late 14th century, first in the sense of "refreshment or curing of a sick person", and derived turn from Latin (''re'': "again", ''creare'': "to create, bring forth, beget"). Prerequisites to leisure People spend their time on activities of daily living, work, sleep, social duties and leisure, the latter time being free from prior commitments to physiologic or social needs, a prerequisite of recreation. Leisure has increased with increased longevity and, for many, with decreased hours spent for physical and economic survival, yet others argue that time pressure has increased for modern people, as they are committed to to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
US Navy 100708-N-4776G-203 Explosive Ordnance Disposal Technician 3rd Class Jonathan Sokol Conducts Training On A AN-PQS 2A Hand Held Sonar
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territories, nine Minor Outlying Islands, and 326 Indian reservations. The United States is also in free association with three Pacific Island sovereign states: the Federated States of Micronesia, the Marshall Islands, and the Republic of Palau. It is the world's third-largest country by both land and total area. It shares land borders with Canada to its north and with Mexico to its south and has maritime borders with the Bahamas, Cuba, Russia, and other nations. With a population of over 333 million, it is the most populous country in the Americas and the third most populous in the world. The national capital of the United States is Washington, D.C. and its most populous city and principal financial center is New York City. Paleo-Ameri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
