Laser-guided bomb

Last updated September 06, 2024

A laser-guided bomb (LGB) is a guided bomb that uses semi-active laser guidance to strike a designated target with greater accuracy than an unguided bomb. First developed by the United States during the Vietnam War, laser-guided bombs quickly proved their value in precision strikes of difficult point targets. These weapons use on-board electronics to track targets that are designated by laser, typically in the infrared spectrum, and adjust their glide path to accurately strike the target. Since the weapon is tracking a light signature, not the object itself, the target must be illuminated from a separate source, either by ground forces, by a pod on the attacking aircraft, or by a separate support aircraft.

Data from the 28,000 laser guided bombs dropped in Vietnam showed that laser-guided bombs achieved direct hits nearly 50% of the time, despite the laser having to be aimed out the side window of the back seat of another aircraft in flight. Unguided bombs had an accuracy rate of just 5.5% per mission, which usually included large numbers of the munitions. Because of this dramatically higher precision, laser-guided munitions can carry less explosive and cause less collateral damage than unguided munitions. Today, laser-guided bombs are one of the most common and widespread guided bombs, used by many of the world's air forces.^[1]

Development

Laser-guided weapons (LGW) were first developed in the United States in the early 1960s. The United States Air Force (USAF) issued the first development contracts in 1964, leading to the development of the Paveway series, which was used operationally in the Vietnam War starting in 1968.^[2]

Originally the project began as a surface-to-air missile seeker developed by Texas Instruments. When TI executive Glenn E. Penisten attempted to sell the new technology to the Air Force, Col. Joe Davis Jr. inquired if it could instead be used as a ground attack system to overcome problems US aircraft were having with the accuracy of bombing in Vietnam. Davis had already witnessed a test of the Army's new laser target designator made by Martin Marietta, but no seeker existed to make use of the system. Davis had already performed tests from the back seat of an F-4 Phantom and proved that it was possible to accurately target objects from a moving aircraft. His mock testing proved correct, and during further testing with live seekers, it took just six attempts to improve the seeker's accuracy from 148 feet (45 m) to within 10 feet (3.0 m) of the target. This greatly exceeded the design requirements. It was commissioned by the USAF in 1967 and two different types, the BOLT-117, and the Paveway I completed a combat evaluation in Vietnam from May to August 1968. Without the existence of tracking pods the Weapon Systems Officer (WSO) in the back seat of an F-4 Phantom II fighter bomber used a hand-held Airborne Laser Designator to guide the bombs, but half of the LGBs still hit their targets despite the difficulties inherent in keeping the laser on the target.^[3] 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. The LGB proved particularly effective against difficult fixed targets like bridges, which previously had required huge loads of "dumb" ordnance to destroy.

It was determined that 48% of Paveways dropped during 1972–73 around Hanoi and Haiphong achieved direct hits, compared with only 5.5% of unguided bombs dropped on the same area a few years earlier.^[4] The average Paveway landed within 23 feet (7.0 m) of its target, as opposed to 447 feet (136 m) for gravity bombs.^[4] 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 (110 km) south of Hanoi, a critical crossing point over the Red River. 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.^[4]

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.

In October 2010, India developed its first Sudarshan laser-guided bomb with the help of IRDE, a lab of DRDO.^[5]

The USAF and other air forces are now seeking to upgrade their LGBs with GPS guidance as a backup. 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 a GPS receiver for backup 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.

Related Research Articles

The GBU-10 Paveway II is an American Paveway-series laser-guided bomb, based on the Mk 84 general-purpose bomb, but with laser seeking capabilities and wings for guidance. Introduced into service c. 1976, it is used today by the USAF, US Navy, US Marine Corps, Royal Australian Air Force and various NATO air forces.

The GBU-12 Paveway II is an American aerial laser-guided bomb, based on the Mk 82 500 lb (230 kg) general-purpose bomb, but with the addition of a nose-mounted laser seeker and fins for guidance. A member of the Paveway series of weapons, Paveway II entered into service c. 1976. It is currently in service with the U.S. Air Force, U.S. Navy, U.S. Marine Corps, and various other air forces.

The Mark 82 is a 500-pound (230 kg) unguided, low-drag general-purpose bomb, part of the United States Mark 80 series. The explosive filling is usually tritonal, though other compositions have sometimes been used.

The Joint Direct Attack Munition (JDAM) is a guidance kit that converts unguided bombs, or "dumb bombs", into all-weather precision-guided munitions (PGMs). JDAM-equipped bombs are guided by an integrated inertial guidance system coupled to a Global Positioning System (GPS) receiver, giving them a published range of up to 15 nautical miles (28 km). JDAM-equipped bombs range from 500 to 2,000 pounds. The JDAM's guidance system was jointly developed by the United States Air Force and United States Navy, hence the "joint" in JDAM. When installed on a bomb, the JDAM kit is given a GBU identifier, superseding the Mark 80 or BLU nomenclature of the bomb to which it is attached.

A glide bomb or stand-off bomb is a standoff weapon with flight control surfaces to give it a flatter, gliding flight path than that of a conventional bomb without such surfaces. This allows it to be released at a distance from the target rather than right over it, allowing a successful attack without exposing the launching aircraft to anti-aircraft defenses near the target. Glide bombs can accurately deliver warheads in a manner comparable to cruise missiles at a fraction of the cost—sometimes by installing flight control kits on simple unguided bombs—and they are very difficult for surface-to-air missiles to intercept due to their tiny radar signatures and short flight times. The only effective countermeasure in most cases is to shoot down enemy aircraft before they approach within launching range, making glide bombs very potent weapons where wartime exigencies prevent this.

Paveway is a series of laser-guided bombs (LGBs).

Missile guidance refers to a variety of methods of guiding a missile or a guided bomb to its intended target. The missile's target accuracy is a critical factor for its effectiveness. Guidance systems improve missile accuracy by improving its Probability of Guidance (Pg).

LANTIRN is a combined navigation and targeting pod system for use on the United States Air Force fighter aircraft—the F-15E Strike Eagle and F-16 Fighting Falcon manufactured by Martin Marietta. LANTIRN significantly increases the combat effectiveness of these aircraft, allowing them to fly at low altitudes, at night and under-the-weather to attack ground targets with a variety of precision-guided weapons.

The Ford Aerospace AN/AVQ-10 Pave Knife was an early targeting pod developed by the USAF and US Navy to designate and guide laser-guided bombs.

A general-purpose bomb is an air-dropped bomb intended as a compromise between blast damage, penetration, and fragmentation in explosive effect. They are designed to be effective against enemy troops, vehicles, and buildings.

The Texas Instruments BOLT-117, retrospectively redesignated as the GBU-1/B was the world's first laser-guided bomb (LGB). It consisted of a standard M117 750-pound (340 kg) bomb case with a KMU-342 laser guidance and control kit. This consisted of a gimballed laser seeker on the front of the bomb and tail and control fins to guide the bomb to the target. The latter used the bang-bang method of control where each control surface was either straight or fully deflected. This was inefficient aerodynamically, but reduced costs and minimized demands on the primitive onboard electronics.

The GBU-16 Paveway II is an American Paveway-series laser-guided bomb, a modified 1,000-pound (450 kg) Mk 83 general-purpose bomb, but with laser seeker and wings for guidance. The GBU-16 was introduced into service around 1976 and is used by the U.S. Air Force, U.S. Navy, U.S. Marine Corps, and various NATO air forces.

<span class="mw-page-title-main">Guided bomb</span> Bomb controllable from an external device

A guided bomb is a precision-guided munition designed to achieve a smaller circular error probable (CEP).

The GBU-44/B Viper Strike glide bomb was a GPS-aided laser-guided variant of the Northrop Grumman Brilliant Anti-Tank (BAT) munition which originally had a combination acoustic and infrared homing seeker. The system was initially intended for use from UAVs, and it was also integrated with the Lockheed AC-130 gunship, giving that aircraft a precision stand-off capability. The Viper Strike design is now owned by MBDA.

LT PGB is an abbreviation for a family of Chinese built precision guided munitions named Fury Precision-guided munition Development CASC. Alternatively, LT PGB is also referred by its laser guidance, as Fury laser-guided bomb, or LT LGB.

<span class="mw-page-title-main">LS PGB</span> Chinese precision bombs

LS is an abbreviation for a family of Chinese built precision-guided munitions (PGM) named Thunder Stone Precision Guided Bomb developed by China Aerospace Science and Technology Corporation (CASC). Alternatively, the LS PGB is also referred to by its gliding capability, as Thunder Stone Gliding Guided Bomb, or LS GGB. The guidance design of LS PGB is also adopted for another family of Chinese PGM, the YZ series, such as YZ-102 series. These PGMs are referred to in China as precision guided bombs (PGB).

A precision-guided munition (PGM), also called a smart weapon, smart munition, or smart bomb, is a guided munition intended to hit a specific target, to minimize collateral damage and increase lethality against intended targets. During the Persian Gulf War guided munitions accounted for only 9% of weapons fired, but accounted for 75% of all successful hits. Despite guided weapons generally being used on more difficult targets, they were still 35 times more likely to destroy their targets per weapon dropped.

The Griffin Laser Guided Bomb is a laser-guided bomb system made by Israel Aerospace Industries' MBT missile division. It is an add-on kit which is used to retrofit existing Mark 82, Mark 83, and Mark 84 and other unguided bombs, making them into laser-guided smart bombs. Initial development completed in 1990.

<span class="mw-page-title-main">GBU-39 Small Diameter Bomb</span> American precision-guided glide bomb

The GBU-39/B Small Diameter Bomb (SDB) is a 250-pound (110 kg) precision-guided glide bomb that is intended to allow aircraft to carry a greater number of smaller, more accurate bombs. Most US Air Force aircraft will be able to carry a pack of four SDBs in place of a single 2,000-pound (910 kg) Mark 84 bomb. It first entered service in 2006. The Ground Launched Small Diameter Bomb (GLSDB) was later developed to enable the SDB to be launched from a variety of ground launchers and configurations.

Sudarshan is an Indian laser-guided bomb kit, developed by Aeronautical Development Establishment (ADE), a DRDO lab with technological support from another DRDO lab Instruments Research and Development Establishment (IRDE), for the Indian Air Force (IAF).

References

Citations

Bibliography

Clancy, Tom (1996). "Ordnance: How Bombs Got 'Smart'". Fighter Wing. London: HarperCollins, 1995. ISBN 0-00-255527-1.

External links

Laser-guided bombs page – FAS

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[1] "Bursts of Brilliance - The Washington Post". The Washington Post .

[2] "Paveway Laser-Guided Bombs - en".

[3] "Bursts of Brilliance - The Washington Post". The Washington Post .

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[5] India develops its first Laser-Guided Bomb

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