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Track-while-scan
Track-while-scan (TWS) is a mode of radar operation in which the radar allocates part of its power to tracking a target or targets (up to forty with modern radar) while part of its power is allocated to scanning. It is similar to but functions differently in comparison to its counterparts range-while-search (RWS), long range search (LRS), air combat mode (ACM), velocity search with ranging (VSR) and combined radar mode (CRM). In track-while-scan mode the radar has the ability to acquire and lock/track multiple targets while simultaneously providing a view of the surrounding airspace, which in turn aids the pilot and or operator in maintaining better situational awareness. Background Early airborne radar systems generally operated purely as tracking systems, with a dedicated radar operator manually "tuning" the system to locate targets in a relatively narrow field-of-view in front of the aircraft. The searching area could be moved using a variety of methods, typically phase-shifting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fire-control Radar
A fire-control radar (FCR) is a radar that is designed specifically to provide information (mainly target azimuth, elevation, range and range rate) to a fire-control system in order to direct weapons such that they hit a target. They are sometimes known as narrow beam radars, targeting radars, tracking radars, or in the UK, gun-laying radars. If the radar is used to guide a missile, it is often known as a target illuminator or illuminator radar. A typical fire-control radar emits a narrow, intense beam of radio waves to ensure accurate tracking information and to minimize the chance of losing track of the target. This makes them less suitable for initial detection of the target, and FCRs are often partnered with a medium-range search radar to fill this role. In British terminology, these medium-range systems were known as tactical control radars. Most modern radars have a track-while-scan capability, enabling them to function simultaneously as both fire-control radar and se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar
Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track aircraft, ships, spacecraft, guided missiles, motor vehicles, map weather formations, and terrain. The term ''RADAR'' was coined in 1940 by the United States Navy as an acronym for "radio detection and ranging". The term ''radar'' has since entered English and other languages as an anacronym, a common noun, losing all capitalization. A radar system consists of a transmitter producing electromagnetic waves in the radio or microwave domain, a transmitting antenna, a receiving antenna (often the same antenna is used for transmitting and receiving) and a receiver and processor to determine properties of the objects. Radio waves (pulsed or continuous) from the transmitter reflect off the objects and return to the receiver, giving ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moscow
Moscow is the Capital city, capital and List of cities and towns in Russia by population, largest city of Russia, standing on the Moskva (river), Moskva River in Central Russia. It has a population estimated at over 13 million residents within the city limits, over 19.1 million residents in the urban area, and over 21.5 million residents in Moscow metropolitan area, its metropolitan area. The city covers an area of , while the urban area covers , and the metropolitan area covers over . Moscow is among the world's List of largest cities, largest cities, being the List of European cities by population within city limits, most populous city entirely in Europe, the largest List of urban areas in Europe, urban and List of metropolitan areas in Europe, metropolitan area in Europe, and the largest city by land area on the European continent. First documented in 1147, Moscow became the capital of the Grand Principality of Moscow, which led the unification of the Russian lan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windmill
A windmill is a machine operated by the force of wind acting on vanes or sails to mill grain (gristmills), pump water, generate electricity, or drive other machinery. Windmills were used throughout the high medieval and early modern periods; the horizontal or panemone windmill first appeared in Persia during the 9th century, and the vertical windmill first appeared in northwestern Europe in the 12th century. Regarded as an icon of Dutch culture, there are approximately 1,000 windmills in the Netherlands today. Forerunners Wind-powered machines have been known earlier, the Babylonian emperor Hammurabi had used wind mill power for his irrigation project in Mesopotamia in the 17th century BC. Later, Hero of Alexandria (Heron) in first-century Roman Egypt described what appears to be a wind-driven wheel to power a machine.Dietrich Lohrmann, "Von der östlichen zur westlichen Windmühle", ''Archiv für Kulturgeschichte'', Vol. 77, Issue 1 (1995), pp. 1–30 (10f.) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propeller
A propeller (often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon a working fluid such as water or air. Propellers are used to pump fluid through a pipe or duct, or to create thrust to propel a boat through water or an aircraft through air. The blades are shaped so that their rotational motion through the fluid causes a pressure difference between the two surfaces of the blade by Bernoulli's principle which exerts force on the fluid. Most marine propellers are screw propellers with helical blades rotating on a propeller shaft (ship), propeller shaft with an approximately horizontal axis. History Early developments The principle employed in using a screw propeller is derived from stern sculling. In sculling, a single blade is moved through an arc, from side to side taking care to keep presenting the blade to the wat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S-400 Missile System
The S-400 Triumf ( – Triumf; translation: Triumph; NATO reporting name: SA-21 Growler), previously known as the S-300 PMU-3, is a mobile surface-to-air missile (SAM) system developed in the 1990s by Russia's NPO Almaz as an upgrade to the S-300 missile system, S-300 family of missiles. The S-400 was approved for service on 28 April 2007 and the first battalion of the systems assumed combat duty on 6 August 2007. The system is complemented by its successor, the S-500 missile system, S-500. Development The development of the S-400 began in the early 1980s to replace the S-200 missile system, S-200 missile system, but was rejected by a state commission due to high cost and inability to address the threat of cruise missiles. In the late 1980s, the programme was revived in under the codename Triumf as a system capable of engaging aircraft at long range plus cruise missiles and stealth aircraft. The Soviet government approved the Truimf programme on 22 August 1991, but the collap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
E Band (NATO)
The NATO E band is a designation given to the radio frequencies from 2000 to 3000 MHz (equivalent to wavelength In physics and mathematics, wavelength or spatial period of a wave or periodic function is the distance over which the wave's shape repeats. In other words, it is the distance between consecutive corresponding points of the same ''phase (waves ...s between 15 and 10 cm) during the cold war period. Since 1992, detailed frequency allocations, allotment and assignments are in line with the NATO Joint Civil/Military Frequency Agreement (NJFA). However, in order to generically identify military radio spectrum requirements, e.g. for crisis management planning, training, electronic warfare activities, radar or in military operations, the NATO band system is often used. References {{EMSpectrum Radio spectrum Military equipment of NATO ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3D Radar
3D radar provides for radar ranging and direction in three dimensions. In addition to range, the more common two-dimensional radar provides only azimuth for direction, whereas the 3D radar also provides elevation. Applications include weather radar, weather monitoring, air defense, and surveillance. The information provided by 3D radar has long been required, particularly for air defence and Ground-controlled interception, interception. Interceptors must be told the altitude to climb to before making an intercept. Before the advent of single unit 3D radars, this was achieved with separate search radars (giving range and azimuth) and separate height finding radars that could examine a target to determine altitude. These had little search capability, so were directed to a particular azimuth first found by the primary search radar. Techniques Steered beam radars steer a narrow beam through a scan pattern to build a 3-D picture. Examples include NEXRAD Pulse-Doppler radar, Doppler ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Generator
In electricity generation, a generator, also called an ''electric generator'', ''electrical generator'', and ''electromagnetic generator'' is an electromechanical device that converts mechanical energy to electrical energy for use in an external circuit. In most generators which are rotating machines, a source of kinetic power rotates the generator's shaft, and the generator produces an electric current at its output terminals which flows through an external circuit, powering electrical loads. Sources of mechanical energy used to drive generators include steam turbines, gas turbines, water turbines, internal combustion engines, wind turbines and even hand cranks. Generators produce nearly all of the electric power for worldwide electric power grids. The first electromagnetic generator, the Faraday disk, was invented in 1831 by British scientist Michael Faraday. The reverse conversion of electrical energy into mechanical energy is done by an electric motor, and motors and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analog Computer
An analog computer or analogue computer is a type of computation machine (computer) that uses physical phenomena such as Electrical network, electrical, Mechanics, mechanical, or Hydraulics, hydraulic quantities behaving according to the mathematical principles in question (''analog signals'') to Scientific modelling, model the problem being solved. In contrast, digital computers represent varying quantities symbolically and by discrete values of both time and amplitude (digital signals). Analog computers can have a very wide range of complexity. Slide rules and nomograms are the simplest, while naval gunfire control computers and large hybrid digital/analog computers were among the most complicated. Complex mechanisms for process control and protective relays used analog computation to perform control and protective functions. Analog computers were widely used in scientific and industrial applications even after the advent of digital computers, because at the time they were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stratosphere
The stratosphere () is the second-lowest layer of the atmosphere of Earth, located above the troposphere and below the mesosphere. The stratosphere is composed of stratified temperature zones, with the warmer layers of air located higher (closer to outer space) and the cooler layers lower (closer to the planetary surface of the Earth). The increase of temperature with altitude is a result of the absorption of the Sun's ultraviolet (UV) radiation by the ozone layer, where ozone is exothermically photolyzed into oxygen in a cyclical fashion. This temperature inversion is in contrast to the troposphere, where temperature decreases with altitude, and between the troposphere and stratosphere is the tropopause border that demarcates the beginning of the temperature inversion. Near the equator, the lower edge of the stratosphere is as high as , at mid-latitudes around , and at the poles about . Temperatures range from an average of near the tropopause to an average of ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
B-52 Stratofortress
The Boeing B-52 Stratofortress is an American long-range, subsonic aircraft, subsonic, jet-powered strategic bomber. The B-52 was designed and built by Boeing, which has continued to provide support and upgrades. It has been operated by the United States Air Force (USAF) since 1955 and was flown by NASA from 1959 to 2007. The bomber can carry up to of weapons and has a typical Range (aeronautics), combat range of around without aerial refueling. After Boeing won the initial contract in June 1946, the aircraft's design evolved from a straight wing, straight-wing aircraft powered by six turboprop engines to the final prototype YB-52 with eight turbojet engines and swept wings. The B-52 took its maiden flight in April 1952. Built to carry nuclear weapons for Cold War Nuclear strategy, deterrence missions, the B-52 Stratofortress replaced the Convair B-36 Peacemaker. The bombers flew under the Strategic Air Command (SAC) until it was disestablished in 1992 and its aircraft abso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
