|
Long Base Line Sonar
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 other two classes are ultra short baseline systems (USBL) and short baseline systems (SBL). LBL systems are unique in that they use networks of sea-floor mounted baseline transponders as reference points for navigation. These are generally deployed around the perimeter of a work site. The LBL technique results in very high positioning accuracy and position stability that is independent of water depth. It is generally better than 1-meter and can reach a few centimeters accuracy. LBL systems are generally employed for precision underwater survey work where the accuracy or position stability of ship-based (SBL, USBL) positioning systems does not suffice. Operation and performance Long baseline systems determine the position of a vehicle or diver by acoustically measuring the distance from a vehicl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LBL Acoustic Positioning System Aquamap Diver
{{disambig ...
LBL can mean: * Laidback Luke, Dutch Music Producer/DJ * Lawrence Berkeley National Laboratory, formerly Lawrence Berkeley Laboratory * Liberal Mid-America Regional Airport, IATA code LBL * Long base line sonar * Latvian Basketball League * Landsforeningen for Bøsser og Lesbiske, former name of LGBT Danmark * Layer by layer, a thin film fabrication technique * Layer by Layer, a Rubik's cube solving technique * Liège–Bastogne–Liège, a one-day classic cycling race in Belgium * London Borough of Lambeth * London Borough of Lewisham Lewisham () is a London boroughs, London borough in south-east London; it forms part of Inner London. The principal settlement of the borough is Lewisham. The local authority is Lewisham London Borough Council, based in Catford. The Prime Merid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Underwater Acoustic Positioning System
An underwater acoustic positioning system is a system for the tracking and navigation of underwater vehicles or divers by means of acoustic distance and/or direction measurements, and subsequent position triangulation. Underwater acoustic positioning systems are commonly used in a wide variety of underwater work, including oil and gas exploration, ocean sciences, salvage operations, marine archaeology, law enforcement and military activities. Method of operation Figure 1 describes the general method of operation of an acoustic positioning system, this is an example of a long baseline (LBL) positioning system for ROV ;Baseline station deployment and survey Acoustic positioning systems measure positions relative to a framework of baseline stations, which must be deployed prior to operations. In the case of a long-baseline (LBL) system, a set of three or more baseline transponders are deployed on the sea floor. The location of the baseline transponders either relative to each ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultra-short Baseline
USBL (ultra-short baseline, also known as SSBL for super short base line) is a method of underwater acoustic positioning. A USBL system consists of a transceiver, which is mounted on a pole under a ship, and a transponder or responder on the seafloor, on a towfish, or on an ROV. A computer, or "topside unit", is used to calculate a position from the ranges and bearings measured by the transceiver. Mechanism An acoustic pulse is transmitted by the transceiver and detected by the subsea transponder, which replies with its own acoustic pulse. This return pulse is detected by the shipboard transceiver. The time from the transmission of the initial acoustic pulse until the reply is detected is measured by the USBL system and is converted into a range. To calculate a subsea position, the USBL calculates both a range and an angle from the transceiver to the subsea beacon. Angles are measured by the transceiver, which contains an array of transducers. The transceiver head normally co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Short Baseline Acoustic Positioning System
A short baseline (SBL) acoustic positioning system is one of three broad classes of underwater acoustic positioning systems that are used to track underwater vehicles and divers. The other two classes are ultra short baseline systems (USBL) and long baseline systems (LBL). Like USBL systems, SBL systems do not require any seafloor mounted transponders or equipment and are thus suitable for tracking underwater targets from boats or ships that are either anchored or under way. However, unlike USBL systems, which offer a fixed accuracy, SBL positioning accuracy improves with transducer spacing. Thus, where space permits, such as when operating from larger vessels or a dock, the SBL system can achieve a precision and position robustness that is similar to that of sea floor mounted LBL systems, making the system suitable for high-accuracy survey work. When operating from a smaller vessel where transducer spacing is limited (i.e. when the baseline is short), the SBL system will exhib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
USS Thresher (SSN-593)
USS ''Thresher'' (SSN-593) was the lead boat of her class of nuclear-powered attack submarines in the United States Navy. She was the U.S. Navy's second submarine to be named after the thresher shark. On 10 April 1963, ''Thresher'' sank during deep-diving tests about east of Cape Cod, Massachusetts, killing all 129 crew and shipyard personnel aboard. It is the second-deadliest submarine incident on record, after the 1942 loss of the French submarine ''Surcouf'', in which 130 crew died. Her loss was a watershed for the U.S. Navy, leading to the implementation of a rigorous submarine safety program known as SUBSAFE. The first nuclear submarine lost at sea, ''Thresher'' was also the third of four submarines lost with more than 100 people aboard, the others being ''Argonaut'', lost with 102 aboard in 1943, '' Surcouf'' sinking with 130 personnel in 1942, and ''Kursk'', which sank with 118 aboard in 2000. Significance of design and loss Created to find and destroy Soviet su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
USNS Mizar (T-AGOR-11)
USNS ''Mizar'' (MA-48/T-AGOR-11/T-AK-272) was a vessel of the United States Navy. She was named after the star Mizar. Cargo ship ''Mizar'' was built as a small ice-strengthened, double hull, cargo ship of the ''Eltanin'' class on a Maritime Administration type (C1-ME2-13a) hull, by Avondale Marine Ways, Inc. from January 1957. She entered service on March 7, 1958, and served as part of the Military Sea Transportation Service (MSTS), working around Canada and Greenland, with a single voyage to Antarctica in 1961. Naval Research Laboratory The loss of the on April 10, 1963, and problems handling heavy search equipment over the side from in 1963 drove the Naval Research Laboratory (NRL) requirement for a larger, more capable ship than the usual oceanographic research type. A search for a candidate ship, capable of being modified for an inboard center well, led to selection of ''Mizar'' in late 1963. In 1964 ''Mizar's'' successful search for the sunken submarine, before modific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bathyscaphe Trieste
''Trieste'' is a Swiss-designed, Italian-built deep-diving research bathyscaphe which reached a record depth of about in the Challenger Deep of the Mariana Trench near Guam in the Pacific. On 23 January 1960, Jacques Piccard (son of the boat's designer Auguste Piccard) and US Navy Lieutenant Don Walsh achieved the goal of Project Nekton. It was the first crewed vessel to reach the bottom of the Challenger Deep. Design ''Trieste'' consisted of a float chamber filled with gasoline (petrol) for buoyancy, with a separate pressure sphere to hold the crew. This configuration (dubbed a "bathyscaphe" by the Piccards) allowed for a free dive, rather than the previous bathysphere designs in which a sphere was lowered to depth and raised again to the surface by a cable attached to a ship. ''Trieste'' was designed by the Swiss scientist Auguste Piccard and originally built in Italy. His pressure sphere, composed of two sections, was built by Acciaierie Terni. The upper part was manufactu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ohio-class Submarine Launches Tomahawk Cruise Missiles (artist Concept)
The ''Ohio'' class of nuclear-powered submarines includes the United States Navy's 14 ballistic missile submarines (SSBNs) and its four cruise missile submarines (SSGNs). Each displacing 18,750 tons submerged, the ''Ohio''-class boats are the largest submarines ever built for the U.S. Navy. They are the world's third-largest submarines, behind the Russian Navy's Soviet-designed 48,000-ton and 24,000-ton . At 24 Trident II missiles apiece, ''Ohio''-class boats carry more missiles than either the Borei class (16, 20 by the Borei II) or the ''Typhoon'' class (20). Like its predecessor - and subs, the ''Ohio''-class SSBNs are part of the United States' nuclear-deterrent triad, along with U.S. Air Force strategic bombers and intercontinental ballistic missiles. The 14 SSBNs together carry about half of U.S. active strategic thermonuclear warheads. Although the Trident missiles have no preset targets when the submarines go on patrol, they can be given targets quickly, from the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LGM-118 Peacekeeper
The LGM-118 Peacekeeper, originally known as the MX for "Missile, Experimental", was a MIRV-capable intercontinental ballistic missile (ICBM) produced and deployed by the United States from 1985 to 2005. The missile could carry up to twelve Mark 21 reentry vehicles (although treaties limited its actual payload to 10), each armed with a 300-kiloton W87 warhead. Initial plans called for building and deploying 100 MX ICBMs, but budgetary concerns eliminated the final procurement; only 50 entered service. Disarmament treaties signed after the Peacekeeper's development led to its withdrawal from service in 2005. Studies on the underlying concept started in the 1960s. The idea was to allow the U.S. to absorb a sneak attack by the USSR with enough warheads surviving to attack the remaining Soviet missile silos. To do so, the missiles had to be highly accurate, be based in such a way that enough would survive a nuclear attack, carry a large number of warheads so the survivors would stil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Navigation
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.Bowditch, 2003:799. The field of navigation includes four general categories: land navigation, marine navigation, aeronautic navigation, and space navigation. It is also the term of art used for the specialized knowledge used by navigators to perform navigation tasks. All navigational techniques involve locating the navigator's position compared to known locations or patterns. Navigation, in a broader sense, can refer to any skill or study that involves the determination of position and direction. In this sense, navigation includes orienteering and pedestrian navigation. History In the European medieval period, navigation was considered part of the set of '' seven mechanical arts'', none of which were used for long voyages across open ocean. Polynesian navigation is probably the earliest form of open-ocean navigation; it was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surveying
Surveying or land surveying is the technique, profession, art, and science of determining the terrestrial two-dimensional or three-dimensional positions of points and the distances and angles between them. A land surveying professional is called a land surveyor. These points are usually on the surface of the Earth, and they are often used to establish maps and boundaries for ownership, locations, such as the designed positions of structural components for construction or the surface location of subsurface features, or other purposes required by government or civil law, such as property sales. Surveyors work with elements of geodesy, geometry, trigonometry, regression analysis, physics, engineering, metrology, programming languages, and the law. They use equipment, such as total stations, robotic total stations, theodolites, GNSS receivers, retroreflectors, 3D scanners, LiDAR sensors, radios, inclinometer, handheld tablets, optical and digital levels, subsurface locators, d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
_underway_c1966.jpg "Click for more on -> USNS Mizar (T-AGOR-11)")
_crop.jpg "Click for more on -> Surveying")