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Encyclopedia > Missile guidance
A guided bomb strikes an underground facility
A guided bomb strikes an underground facility

Missile guidance technologies of missile systems use a variety of methods to guide a missile to its intended target. These can generally be classified into a number of categories, with the broadest categories being active vs. passive vs. preset. Image File history File linksMetadata Download high resolution version (400x945, 211 KB) Source: 3 separate images from http://www. ... Image File history File linksMetadata Download high resolution version (400x945, 211 KB) Source: 3 separate images from http://www. ... Exocet missile in flight A missile (see also pronunciation differences) is a projectile propelled as a weapon at a target. ...


Passive systems use signals generated by the target itself as a signal on which to "home in". A number of such systems have been developed, but by far the most common are sound in the case of torpedoes and infrared in the case of air-to-air missiles. A modern torpedo, historically called a locomotive torpedo, is a self-propelled projectile that (after being launched above or below the water surface) operates underwater and is designed to detonate on contact or in proximity to a target. ... Image of a small dog taken in mid-infrared (thermal) light (false color) Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of radio waves. ... A US Navy VF-103 Jolly Rogers F-14 Tomcat fighter launchers an AIM-54 Phoenix long-range air-to-air missile. ...


Active systems use some "input" signal instead. One common sort of signal is a controller who watches the missile and sends corrections to its flight path. Another common system is to use radar signals or radio control. The semi-active radar homing is a crossover, homing passively on a reflected active radar signal generated by some other system. This long range RADAR antenna, known as ALTAIR, is used to detect and track space objects in conjunction with ABM testing at the Ronald Reagan Test Site on the Kwajalein atoll[1]. RADAR is a system that uses radio waves to detect, determine the direction and distance and/or speed... This radio control airplane is carrying a scale model of X-33 and is taking part in NASA research. ... Semi-active radar homing, or SARH, is a common type of missile guidance system, perhaps the most common type for longer range air-to-air and ground-to-air missile systems. ...


Preset systems are used to attack targets at fixed locations, such as military bases and cities.

  • command guided, an active system in which signals are sent to the missile using radio control or some similar system. more specifically the term is typically used to describe anti-aircraft systems in which the tracking and guidance systems are all ground-based.
  • MCLOS, manually command to line of sight, the operator watches the missile flight and uses some sort of signaling system to command the missile back into the straight line between the operator and the target (the "line of sight"). Typically useful only for slower targets where significant "lead" is not required. MCLOS is a subtype of command guided systems. In the case of glide bombs missiles against ships or the supersonic Wasserfall against slow-moving B-17 bombers this system worked fine, but as speeds increased MCLOS was quickly rendered useless for most roles.
  • SACLOS, semi-automatic command to line of sight, is similar to MCLOS but some automatic system positions the missile in the line of sight while the operator simply tracks the target. SACLOS has the advantage of allowing the missile to start in a position invisible to the user, as well as generally being considerable easier to operate. SACLOS is the most common form of guidance against ground targets such as tanks and bunkers.
  • beam riding, in which a "beam" of some sort, typically radio or laser, is pointed at the target and detectors on the rear of the missile keep it centered in the beam. Beam riding systems are often SACLOS, but don't have to be, in other systems the beam is part of an automated radar tracking system.
  • active radar homing uses a radar on the missile to provide a guidance signal. Typically electronics in the missile keep the radar pointed directly at the target, and the missile then looks at this "angle off" its own centerline to guide itself. Radar resolution is based on the size of the antenna, so in a smaller missile these systems are useful for attacking only large targets, ships or large bombers for instance. Active radar systems remain in widespread use in anti-shipping missiles, and in "fire and forget" air-to-air missile systems such as AMRAAM and R-77
  • semi-active radar homing (SARH) systems combine a radar receiver on the missile with a radar broadcaster located "elsewhere". Since the missile is typically being launched after the target was detected using a powerful radar system, it makes sense to use that same radar system to track the target, thereby avoiding problems with resolution or power. SARH is by far the most common "all weather" guidance solution for anti-aircraft systems, both ground and air launched. SALH is a similar system using a laser as a signal.
  • Infrared homing, a passive system in which heat generated by the target is detected and homed on. Typically used in the anti-aircraft role to track the heat of jet engines, it has also been used in the anti-vehicle role with some success. This means of guidance is sometimes also referred to as "heatseeking".
  • inertial guidance uses sensitive measurement devices to calculate the location of the missile due to the acceleration put on it after leaving a known position. Early mechanical systems were not very accurate, and required some sort of external adjustment to allow them to hit targets even the size of a city. Modern systems use solid state ring gyros that are accurate to within metres over ranges of 10,000km, and no longer require additional inputs. Gyroscope development has culminated in the highly accurate 'baryllium baby' floating gyro found on the MX missile, allowing for an accuracy of less than 100m at intercontinental ranges. Many civilian aircraft use inertial guidance using the ring laser gyro, which is less accurate than the mechanical systems found in ICBMs, but which provide an inexpensive means of attaining a fairly accurate fix on location (when most airliners such as Boeing's 707 and 747 were designed, GPS was not the widely commercially available means of tracking that it is today). Today guided weapons can use a combination of INS, GPS and radar terrain mapping to achieve extremely high levels of accuracy such as that found in modern cruise missiles.
  • Stellar-inertial guidance was first used in the American Poseidon missile and uses star positioning to fine-tune the accuracy of the inertial guidance system after launch. As the accuracy of a ballistic missile is dependent upon the guidance system knowing the exact position of the rocket at any given moment during its boost phase, the fact that stars are a fixed reference point from which to calculate that position makes this a potentially very effective means of improving accuracy. In the Polaris system this was achieved by a single camera that was trained to spot just one star in its expected position (it is believed that the missiles from Soviet submarines would track two separate stars to achieve this), if it was not quite aligned to where it should be then this would indicate that the inertial system was not precisely on target and a correction would be made. Apparently this system is sufficiently sensitive to detect stars in daylight.
  • TERCOM, for "terrain contour matching", uses altitude maps of the strip of land from the launch site to the target, and compares them with information from a radar altimeter onboard. More sophisticated TERCOM systems allow the missile to fly a complex route over a full 3D map, instead of flying directly to the target. TERCOM is the typical system for cruise missile guidance, but is being supplanted by GPS systems and by DSMAC, Digital Scene-Matching Area Correlator, which employs a camera to view an area of land, digitizes the view, and compares it to stored scenes in an onboard computer to guide the missile to its target.
  • Contrast seekers use a television camera, typically black and white, to image a field of view in front of the missile, which is presented to the operator. When launched, the electronics in the missile look for the spot on the image where the contrast changes the fastest, both vertically and horizontally, and then attempts to keep that spot at a constant location in its view. Contrast seekers have been used for air-to-ground missiles, including the famous AGM-65 Maverick, because most ground targets can be distinguished only by visual means. However they rely on there being strong contrast changes to track, and even traditional camouflage can render them unable to "lock on".

Command guidance is a type of missile guidance in which a ground station or aircraft relay signals to a guided missile via radio (or possibly through a wire connecting the missile to the launcher) and tell the missile where to steer in order to intercept its target. ... This radio control airplane is carrying a scale model of X-33 and is taking part in NASA research. ... MCLOS (short for Manual Command to Line of Sight) is a first-generation method for guiding guided missiles. ... A glide bomb is an aerial bomb that is modified with aerodynamic surfaces to modify its flight path from a purely ballistic one, to a flatter, gliding, one. ... It has been suggested that hypersonic be merged into this article or section. ... Wasserfall (German for Waterfall) was a German surface-to-air missile developed during World War II. It never reached operational status although it was well developed and likely ready for operation, and the project was cancelled in February 1945. ... A B_17 nicknamed Sally B in England in 2001 The B_17 Flying Fortress was the first mass_produced, four_engine heavy bomber. ... SACLOS (short for Semi-Automatic Command to Line-Of-Sight) is a second-generation method of missile guidance. ... Beam-riding guidance leads a missile to its target by means of radar or a laser beam. ... // Experiment using a (likely argon) laser. ... Active radar homing is a type of missile guidance where a guided missile contains a radar transceiver and the electronics necessary for it to find and track its target autonomously. ... Angular resolution describes the resolving power of any optical device such as a telescope, a microscope, a camera, or an eye. ... The AIM-120 Advanced Medium-Range, Air-to-Air Missile, or AMRAAM (pronounced am-ram), commonly known to air crews as the Slammer, is a new generation air-to-air missile, developed as the result of an agreement between the United States and other NATO countries (see below). ... The Russian R-77RVV-AE Missile (NATO designation: AA-12 Adder) is a medium range, air-to-air, radar-guided missile system. ... Semi-active radar homing, or SARH, is a common type of missile guidance system, perhaps the most common type for longer range air-to-air and ground-to-air missile systems. ... Sarh (formerly Fort Archambault) is the largest city in southern Chad, the capital of Moyen-Chari region and the department of Barh Köh. ... SALH may stand for: Semi-active laser homing, a form of laser guidance The South Alberta Light Horse This is a disambiguation page — a navigational aid which lists pages that might otherwise share the same title. ... Track-via-missile (or TVM) refers to a missile guidance technique which combines many of the best features of semi-active radar homing (SARH) and radio command guidance. ... Command guidance is a type of missile guidance in which a ground station or aircraft relay signals to a guided missile via radio (or possibly through a wire connecting the missile to the launcher) and tell the missile where to steer in order to intercept its target. ... Semi-active radar homing, or SARH, is a common type of missile guidance system, perhaps the most common type for longer range air-to-air and ground-to-air missile systems. ... Active radar homing is a type of missile guidance where a guided missile contains a radar transceiver and the electronics necessary for it to find and track its target autonomously. ... Infra-red homing refers to a guidance system which uses the infra-red light emission from a target to track it. ... American troops man an anti-aircraft gun near the Algerian coastline in 1943 Anti-aircraft, or air defense, is any method of combating military aircraft from the ground. ... An inertial navigation system measures the position and altitude of a vehicle by measuring the accelerations and rotations applied to the systems inertial frame. ... In electronics, solid state circuits are those that do not contain vacuum tubes. ... Terrain Contour Matching (TERCOM) navigation system uses an on-board contour map of the terrain that a cruise missile will be flying over. ... A Radar Altimeter measures altitude above the terrain presently beneath the aircraft. ... A Tomahawk cruise missile A cruise missile is a guided missile which uses a lifting wing and most often a jet propulsion system to allow sustained flight. ... Over fifty GPS satellites such as this NAVSTAR have been launched since 1978. ... A professional video camera (often called a television camera even though the use has spread) is a high-end device for recording electronic moving images (as opposed to a movie camera, that records the images on film). ... The AGM-65 Maverick is an air-to-surface tactical missile (ASM) designed for close air support, prohibition, and forceful prevention. ... Anolis caroliensis showing blending camouflage and counter-shading. ...

See also


  Results from FactBites:
 
Missile guidance - Wikipedia, the free encyclopedia (1195 words)
Missile guidance technologies of missile systems use a variety of methods to guide a missile to its intended target.
Stellar-inertial guidance was first used in the American Poseidon missile and uses star positioning to fine-tune the accuracy of the inertial guidance system after launch.
TERCOM is the typical system for cruise missile guidance, but is being supplanted by GPS systems and by DSMAC, Digital Scene-Matching Area Correlator, which employs a camera to view an area of land, digitizes the view, and compares it to stored scenes in an onboard computer to guide the missile to its target.
missile: Definition and Much More from Answers.com (1411 words)
Missiles are often used in warfare as a means of delivering destructive force (usually in the form of an explosive warhead) upon a target.
Aside from explosives, other possible types of destructive missile payloads are various forms of chemical or biological agents, nuclear warheads, or simple kinetic energy (where the missile destroys the target by the force of striking it at high speed).
Missiles which spend most of their trajectory in unpowered flight, and which don't use aerodynamics to alter their course, are known as ballistic missiles (because their motion is largely governed by the laws of ballistics).
  More results at FactBites »

 
 

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