A guided bomb (also known as a smart bomb, guided bomb unit, or GBU) is a precision-guided munition designed to achieve a smaller circular error probable (CEP). [1] [2]
The creation of precision-guided munitions resulted in the retroactive renaming of older bombs as unguided bombs or "dumb bombs".
Guided bombs carry a guidance system which is usually monitored and controlled from an external device. A guided bomb of a given weight must carry fewer explosives to accommodate the guidance mechanisms.
The Germans were first to introduce Precision Guided Munitions (PGMs) in combat, using the 1,400-kg (3,100 lb) MCLOS-guidance Fritz X to successfully attack the Italian battleship Roma in September 1943. The closest Allied equivalents were the 1,000-lb (454 kg) AZON (AZimuth ONly), used in both Europe and the CBI Theater, and the US Navy's Bat, primarily used in the Pacific Theater of World War II which used autonomous, on-board radar guidance. In addition, the U.S. tested the rocket-propelled Gargoyle; it never entered service. [3] No Japanese remotely guided PGMs ever saw service in World War II.
The United States Army Air Forces used similar techniques with Operation Aphrodite, but had few successes; the German Mistel (Mistletoe) "parasite aircraft" was no more effective.
The U.S. programs restarted in the Korean War. In the 1960s, the electro-optical bomb (or camera bomb) was reintroduced. They were equipped with television cameras and flare sights, by which the bomb would be steered until the flare superimposed the target. The camera bombs transmitted a "bomb's eye view" of the target back to a controlling aircraft. An operator in this aircraft then transmitted control signals to steerable fins fitted to the bomb. Such weapons were used increasingly by the USAF in the last few years of the Vietnam War because the political climate was increasingly intolerant of civilian casualties, and because it was possible to strike difficult targets (such as bridges) effectively with a single mission; the Thanh Hoa Bridge, for instance, was attacked repeatedly with gravity bombs, to no effect, only to be dropped in one mission with PGMs.
Although not as popular as the newer JDAM and JSOW weapons, or even the older laser-guided bomb systems, weapons like the AGM-62 Walleye TV-guided bomb are still being used, in conjunction with the AAW-144 Data Link Pod, on US Navy F/A-18 Hornets.
In World War II, the U.S. National Defense Research Committee developed the VB-6 Felix, which used infrared to home on ships. While it entered production in 1945, it was never employed operationally. [4]
In 1962, the US Army began research into laser guidance systems and by 1967 the USAF had conducted a competitive evaluation leading to full development of the world's first laser-guided bomb, the BOLT-117, in 1968. All such bombs work in much the same way, relying on the target being illuminated, or "painted," by a laser target designator on the ground or on an aircraft. They have the significant disadvantage of not being usable in poor weather where the target illumination cannot be seen, or where it is not possible to get a target designator near the target. The laser designator sends its beam in a series of encrypted pulses so the bomb cannot be confused by an ordinary laser, and also so multiple designators can operate in reasonable proximity.
Laser-guided weapons did not become commonplace until the advent of the microchip. They made their practical debut in Vietnam, where on 13 May 1972 when they were used in the second successful attack on the Thanh Hoa Bridge ("Dragon's Jaw"). This structure had previously been the target of 800 American sorties [5] (using unguided weapons) and was partially destroyed in each of two successful attacks, the other being on 27 April 1972 using Walleyes. That first mission also had laser-guided weapons, but bad weather prevented their use. They were used, though not on a large scale, by the British forces during the 1982 Falklands War. [6] The first large-scale use of smart weapons came in 1991 during Operation Desert Storm when they were used by coalition forces against Iraq. Even so, most of the air-dropped ordnance used in that war was "dumb," although the percentages are biased by the large use of various (unguided) cluster bombs. Laser-guided weapons were used in large numbers during the 1999 Kosovo War, but their effectiveness was often reduced by the poor weather conditions prevalent in the southern Balkans.
There are two basic families of laser-guided bombs in American (and American-sphere) service: the Paveway II and the Paveway III. The Paveway III guidance system is more aerodynamically efficient and so has a longer range, however it is more expensive. Paveway II 500-pound LGBs (such as GBU-12) are a cheaper lightweight PGM suitable for use against vehicles and other small targets, while a Paveway III 2000-pound penetrator (such as GBU-24) is a more expensive weapon suitable for use against high-value targets. GBU-12s were used to great effect in the first Gulf War, dropped from F-111F aircraft to destroy Iraqi armored vehicles in a process referred to as "tank plinking."
Lessons learned during the first Gulf War showed the value of precision munitions, yet they also highlighted the difficulties in employing them—specifically when visibility of the ground or target from the air was degraded. [7] The problem of poor visibility does not affect satellite-guided weapons such as Joint Direct Attack Munition (JDAM) and Joint Stand-Off Weapon (JSOW), which make use of the United States' GPS system for guidance. This weapon can be employed in all weather conditions, without any need for ground support. Because it is possible to jam GPS, the guidance package reverts to inertial navigation in the event of GPS signal loss. Inertial navigation is significantly less accurate; the JDAM achieves a published circular error probable (CEP) of 13 m under GPS guidance, but typically only 30 m under inertial guidance (with free fall times of 100 seconds or less). [8] [9]
The precision of these weapons is dependent both on the precision of the measurement system used for location determination and the precision in setting the coordinates of the target. The latter critically depends on intelligence information, not all of which is accurate. According to a CIA report, the accidental bombing of the Chinese embassy in Belgrade during Operation Allied Force by NATO aircraft was attributed to faulty target information. [10] However, if the targeting information is accurate, satellite-guided weapons are significantly more likely to achieve a successful strike in any given weather conditions than any other type of precision-guided munition. Other military satellite guidance systems include: Russian GLONASS, European Galileo (satellite navigation), Chinese BeiDou Navigation Satellite System, regional Indian Regional Navigation Satellite System, Japanese regional Quasi-Zenith Satellite System.
The guided bomb had its origins in World War II. Its usage increased after the success of the weapon in the Gulf War.
In World War II, the aforementioned Fritz X and Henschel Hs 293 guided ordnance designs were used in combat by Nazi Germany against ships, as the USAAF would do with the Azon in hitting bridges and other hard-to-hit targets in both Western Europe and Burma. Later, U.S. National Defense Research Committee developed the VB-6 Felix, which used infrared to home on ships. While it entered production in 1945, it was never employed operationally. [11]
The US briefly deployed the ASM-A-1 Tarzon (or VB-13 Tarson) bomb (a Tallboy fitted with radio guidance) during the Korean War, dropping them from Boeing B-29 Superfortresses.
In 1962, the US Army began research into laser guidance systems and by 1967 the USAF had conducted a competitive evaluation leading to full development of the world's first laser-guided bomb, the BOLT-117, in 1968.
GBU-12 Paveway IIs were used to great effect in the first Gulf War, dropped from F-111F aircraft to destroy Iraqi armored vehicles in a process referred to as "tank plinking".
Lessons learned during the first Gulf War showed the value of guided bombs, with precision-guided munitions accounting for 70% of munitions expended during Operation Enduring Freedom. [12]
Responding to after-action reports from pilots who employed laser and/or satellite guided weapons, Boeing has developed a Laser JDAM (LJDAM) to provide both types of guidance in a single kit. Based on the existing JDAM configurations, a laser guidance package is added to a GPS/INS guided weapon to increase the overall accuracy of the weapons. [13] Raytheon has developed the Enhanced Paveway family, which adds GPS/INS guidance to their Paveway family of laser-guidance packages. [14] These "hybrid" laser and GPS guided weapons permit the carriage of fewer weapons types, while retaining mission flexibility, because these weapons can be employed equally against moving and fixed targets, or targets of opportunity. For instance, a typical weapons load on an F-16 flying in the Iraq War included a single 2,000-lb JDAM and two 500-lb LGBs. With LJDAM, and the new Small Diameter Bomb, these same aircraft can carry more bombs if necessary, and have the option of satellite or laser guidance for each weapon release.
The GBU-12 Paveway II is an American aerial laser-guided bomb, based on the Mk 82 500-pound (227 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 84 or BLU-117 is a 2,000-pound (900 kg) American general-purpose bomb. It is the largest of the Mark 80 series of weapons. Entering service during the Vietnam War, it became a commonly used US heavy unguided bomb to be dropped. At the time, it was the third largest bomb by weight in the US inventory behind the 15,000-pound (6,800 kg) BLU-82 "Daisy Cutter" and the 3,000-pound (1,400 kg) M118 "demolition" bomb. It is currently sixth in size due to the addition of the 5,000 lb (2,300 kg) GBU-28 in 1991, the 22,600 lb (10,300 kg) GBU-43/B Massive Ordnance Air Blast bomb (MOAB) in 2003, and the 30,000 lb (14,000 kg) Massive Ordnance Penetrator.
The Mark 83 is a 1,000-pound (450 kg) bomb, part of the Mark 80 series of low-drag general-purpose bombs in United States service.
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. 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).
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.
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 "SPICE" is an Israeli-developed, EO/GPS- guidance kit used for converting air-droppable unguided bombs into precision-guided bombs.
GBU may refer to:
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.
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.
The GBU-39/B Small Diameter Bomb (SDB) is a 250-pound (110 kg) precision-guided glide bomb that is intended to provide aircraft with the ability to carry a higher number of 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) 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.
The Umbani is a precision-guided bomb kit manufactured by Denel Dynamics in South Africa. It consists of a number of modules fitted to NATO standard Mk81, Mk82 or Mk83 low drag free-fall bombs to convert them into guided glide bombs.
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).
