A laser-guided bomb (LGB) is a precision-guided munition (PGM) that uses semi-active laser homing to strike a designated target with greater accuracy than a free-fall bomb. Laser guidance is a technique of guiding a missile or other projectile or vehicle to a target by means of a laser beam LGBs are one of the most common and widespread PGMs, used by a large number of the world's air forces.
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Overview
Laser-guided munitions use a laser designator to mark (illuminate) a target. The Texas Instruments BOLT-117 (BOmb Laser Terminal-117 also known as the GBU-1/B was the world's first Laser guided bomb (LGB A laser designator is a Laser light source which is used to illuminate a target The reflected laser light ("sparkle") from the target is then detected by the seeker head of the weapon, which sends signals to the weapon's control surfaces to guide it toward the designated point. Laser-guided bombs are generally unpowered, using small wings to glide towards their targets. Powered laser-guided missiles, such as some variants of the US AGM-65 Maverick and the French AS. The United States of America —commonly referred to as the The AGM-65 Maverick is an air-to-ground tactical missile (AGM designed for close air support This article is about the country For a topic outline on this subject see List of basic France topics. 30L, use the same guidance system, but have greater range and maneuverability because they are not limited to unpowered flight. Some LGBs have been fitted with strap-on rocket motors to increase their range; one such weapon is the USAF AGM-123 Skipper. A rocket engine is a Jet engine that uses only Propellant mass for forming its high speed propulsive jet.
The earliest laser guidance seekers measured the intensity of the reflected laser light at four corners of the seeker window. The seeker then actuated the control fins to steer the weapon in the direction of the strongest signal return, thereby keeping the weapon centered on the laser sparkle. Later weapons have more sensitive seekers and more sophisticated control systems that waste less energy with course corrections, improving accuracy and range, but the principle remains essentially the same. The first such weapon to be developed was the Texas Instruments BOLT-117. The Texas Instruments BOLT-117 (BOmb Laser Terminal-117 also known as the GBU-1/B was the world's first Laser guided bomb (LGB
Most laser-guided bombs are produced in the form of strap-on kits: seeker heads, steering fins, and wings that can be attached to a standard general-purpose bomb or penetration bomb. A general-purpose bomb is an air-dropped Bomb intended as a compromise between blast damage penetration and fragmentation in explosive effect Such kits are modular, allowing relatively easy upgrades, and are considerably cheaper than purpose-built weapons.
Development
Laser-guided weapons were first developed in the United States in the early 1960s. The 1960s decade refers to the years from the beginning of 1960 to the end of 1969 The USAF issued the first development contracts in 1964, leading to the development of the Paveway series, which was used operationally in Vietnam starting in 1968. For the year see 1964 This is a list of Aviation -related events from 1964: Events January January Paveway is a trademark of Raytheon Company which identifies its variants of Laser Guided Bombs (LGB The Vietnam War, also known as the Second Indochina War, or the Vietnam Conflict, occurred in Vietnam, Laos and Cambodia This is a list of Aviation -related events from 1968: Events January January 21 - a US Air Force B-52 Stratofortress Although there were a variety of technical and operational problems, the results were generally positive. LGBs proved to offer a much higher degree of accuracy than unguided weapons, but without the expense, complexity, and limitations of guided air-to-ground missiles like the AGM-12 Bullpup. An air-to-surface missile (also air-to-ground missile, AGM, ASM or ATGM) is a Missile designed to be launched from Military The AGM-12 Bullpup is an air-to-ground missile which was used on the A-4 Skyhawk, A-6 Intruder and F-4 Phantom among others The LGB proved particularly effective against difficult fixed targets like bridges, which previously had required huge loads of "dumb" ordnance, and large numbers of sorties, to destroy.
It was determined that 48 percent of Paveways dropped during 1972–73 around Hanoi and Haiphong achieved direct hits, compared with only 5. Hanoi ( Vietnamese: Hà Nội Hán Tự: 河[[wikt 内|内]], estimated population 3398889 (2007, is the Capital of Vietnam 5 percent of unguided bombs dropped on the same area a few years earlier. [1] The average Paveway landed within 23 feet of its target, as opposed to 447 feet for gravity bombs. [1] The leap in accuracy brought about primarily by laser guidance made it possible to take out heavily defended, point objectives that had eluded earlier air raids. The most dramatic example was the Thanh Hoa Bridge, 70 miles south of Hanoi, a critical crossing point over the Red River. The Thanh Hoa Bridge, spanning the Song Ma river is situated north east of Thanh Hóa, the capital of Thanh Hoa Province in Vietnam. There are also other rivers named Red River. The Red River, also known as the Hong - Red Song Cai, Song Ca Starting in 1965, U. S. pilots had flown 871 sorties against it, losing 11 planes without managing to put it out of commission. In 1972 the “Dragon’s Jaw” bridge was attacked with Paveway bombs, and 14 jets managed to do what the previous 871 had not: drop the span, and cut a critical North Vietnamese supply artery. [1]
In the wake of this success, other nations, specifically the Soviet Union, France, and Great Britain, began developing similar weapons in the late 1960s and early 1970s, while US weapons were refined based on combat experience. This article is about the Decade 1970-1979 For the Year 1970 see 1970.
The USAF and other air forces are now seeking to upgrade their LGBs with GPS guidance as a back-up. Basic concept of GPS operation A GPS receiver calculates its position by carefully timing the signals sent by the constellation of GPS Satellites high above the Earth These weapons, such as the USAF Enhanced Guided Bomb Unit (part of the Paveway family), use laser designation for precision attacks, but contain an inertial navigation system with GPS receiver for back-up, so that if the target illumination is lost or broken, the weapon will continue to home in on the GPS coordinates of the original target. An Inertial Navigation System (INS is a Navigation aid that uses a Computer and motion sensors to continuously track the position orientation and Velocity
Problems and Limitations
While LGBs are highly accurate under ideal conditions, they present several challenges for successful use, making them somewhat less than the "silver bullet" sometimes suggested.
The first problem is designation. To ensure accurate guidance, the target must be illuminated for several seconds before launch, allowing the weapon's seeker to obtain a positive lock, and the target must remain illuminated during much of the weapon's transit time. If the designator's "sparkle" is turned off, blocked, or moved, the weapon's accuracy will be greatly reduced.
For an accurate attack against a small target, uninterrupted designation is essential. But, the guidance controls of many LGBs (such as the American Paveway II) cause large deflections (visible as a noticeable wobble) which reduce the bomb's range. To compensate, crews will often release their weapons in an unguided, ballistic arc, activating the designator only to refine the bomb's final impact point. This is more demanding of crew and aircraft, requiring a high standard of basic, unguided bombing accuracy and more attention to the bomb's flight.
Laser designation is very sensitive and vulnerable to weather conditions. Cloud cover, rain, and smoke often make reliable designation impossible. In war conditions, many attacks have been aborted due to poor visibility.
In the 1970s and 1980s it was common for aircraft to rely on a separate designator, either carried by ground forces, operated by the forward air controller, or carried by another aircraft in the strike group. This article is about the Decade 1970-1979 For the Year 1970 see 1970. The 1980s was the decade spanning from January 1 1980 to December 31 1989. It was often deemed more practical for one aircraft to designate for its comrades. Modern conflicts and a growing emphasis on precision-guided weapons have pointed to the need for autonomous designation, and many fighter-bomber aircraft are now being fitted with designator pods to self-designate for laser-guided munitions. Ground-attack aircraft are military aircraft designed to attack targets on the ground and are often deployed as Close air support for and in proximity to their own ground forces
Even if the launch aircraft is capable of autonomous designation, problems remain. Laser illumination can be interrupted by smoke, fog, or clouds, limiting the usefulness of LGBs in poor weather or very dusty conditions. In desert warfare, such as the 1991 Gulf War, laser designation sometimes reflected off the sand, causing weapons to home on false targets. Furthermore, the need to provide designation may leave the aircraft dangerously exposed to ground fire or enemy air support.
An additional concern is the limited "launch envelope" of an unguided weapon. The reflected laser "sparkle" can be described as a basket into which the weapon must be steered to hit the target. If the weapon is released too low or to far from the target, or in a trajectory that puts the weapon outside the seeker's field of view, it is likely to miss. Optimum altitude for an effective LGB attack is relatively high, increasing the aircraft's vulnerability to surface-to-air missile (SAM) attacks. A surface to air missile ( SAM) or ground-to-air missile ( GTAM) is a Missile designed to be launched from the ground to destroy Aircraft
For these reasons, while all modern air forces have put an increasing emphasis on LGBs and other precision-guided munitions, some tacticians still see an important role for the accurate delivery of unguided bombs. During their 1981 raid on the Iraqi nuclear reactor at Osirak, the Israeli Air Force chose to use unguided Mark 84 bombs rather than laser-guided weapons because they felt the need to designate the target would leave the attackers unacceptably vulnerable. Year 1981 ( MCMLXXXI) was a Common year starting on Thursday (link displays the 1981 For a topic outline on this subject see List of basic Iraq topics. This article is a subarticle of Nuclear power. A nuclear reactor is a device in which Nuclear chain reactions are initiated controlled Osirak, also spelled Osiraq, (French Osirak Iraqi Tammuz 1 was a 40 MW light-water nuclear materials testing reactor (MTR in The Israeli Air Force ( IAF; Hebrew: זרוע האויר והחלל Zroa HaAvir VeHahalal, "Air and Space Arm" commonly known as חיל The Mark 84 is an American General-purpose bomb, the largest of the Mark 80 series of weapons
See also
External links
References
Overview The JDAM is not a weapon rather it is a "bolt-on" upgrade for unguided gravity bombs installed during build up of the munition by Naval Ordnancemen or Air Force The KAB-500L is a Laser-guided bomb developed by the Soviet Air Force. Laser guidance is a technique of guiding a missile or other projectile or vehicle to a target by means of a laser beamDapyx Software network: MP3 Explorer | Ebook Manager | Zenithic