Wikipedia

Guided bomb

"Smart bomb" redirects here. For other uses, seeSmart bomb (disambiguation).

Aguided bomb(also known as asmart bomb,guided bomb unit,orGBU) is aprecision-guided munitiondesigned to achieve a smallercircular error probable(CEP).[1][2]

BOLT-117,the world's firstlaser-guided bomb

The creation of precision-guided munitions resulted in the retroactive renaming of older bombs asunguided bombsor "dumb bombs".

Guidance

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Main article:Missile guidance
A laser-guidedGBU-24(BLU-109warhead variant) strikes its target.

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.

Radio

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Main article:Command guidance

The Germans were first to introduce Precision Guided Munitions (PGMs) in combat, using the 1,400-kg (3,100 lb)MCLOS-guidanceFritz Xto successfully attack the ItalianbattleshipRomain September 1943. The closestAlliedequivalents were the 1,000-lb (454 kg)AZON(AZimuth ONly), used in both Europe and theCBI Theater,and theUS Navy'sBat,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-propelledGargoyle;it never entered service.[3]No Japanese remotely guided PGMs ever saw service in World War II.

TheUnited States Army Air Forcesused similar techniques withOperation Aphrodite,but had few successes; the GermanMistel(Mistletoe) "parasite aircraft"was no more effective.

The U.S. programs restarted in theKorean War.In the 1960s, theelectro-opticalbomb(orcamera bomb) was reintroduced. They were equipped withtelevisioncamerasand 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 theUSAFin the last few years of theVietnam Warbecause 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; theThanh 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 newerJDAMandJSOWweapons, or even the olderlaser-guided bombsystems, weapons like theAGM-62 WalleyeTV-guided bomb are still being used, in conjunction with theAAW-144Data Link Pod, onUS NavyF/A-18 Hornets.

Infrared

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Main article:Infrared homing

In World War II, the U.S.National Defense Research Committeedeveloped theVB-6 Felix,which used infrared to home on ships. While it entered production in 1945, it was never employed operationally.[4]

Laser

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Main article:Laser guidance
GBU-10 shortly before it impacts a small boat during a training exercise

In 1962, the US Army began research intolaserguidance systems and by 1967 the USAF had conducted a competitive evaluation leading to full development of the world's firstlaser-guided bomb,theBOLT-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 ofencryptedpulses 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 usingWalleyes.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 1982Falklands War.[6]The first large-scale use of smart weapons came in 1991 during OperationDesert Stormwhen they were used by coalition forces againstIraq.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 1999Kosovo 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: thePavewayII 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 firstGulf War,dropped fromF-111Faircraft to destroy Iraqi armored vehicles in a process referred to as "tank plinking."

Satellite

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AnF-22releases aJDAMfrom its center internal bay while flying at supersonic speed

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 asJoint Direct Attack Munition(JDAM) andJoint Stand-Off Weapon(JSOW), which make use of the United States'GPSsystem for guidance. This weapon can be employed in all weather conditions, without any need for ground support. Because it is possible tojamGPS, the guidance package reverts toinertial navigationin 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]

HOPE/HOSBOof theLuftwaffewith a combination of GPS/INS and electro-optical guidance

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 accidentalbombing of the Chinese embassy in BelgradeduringOperation Allied Forceby NATO aircraft was attributed to faulty target information.[10]However, if the targeting informationisaccurate, 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: RussianGLONASS,EuropeanGalileo,ChineseBeiDou Navigation Satellite System,Indian Regional Navigation Satellite System,Japanese regionalQuasi-Zenith Satellite System.

History

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The guided bomb had its origins inWorld War II.Its usage increased after the success of the weapon in the Gulf War.

World War II

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ABAT guided bomb

In World War II, the aforementioned Fritz X andHenschel Hs 293guided ordnance designs were used in combat by Nazi Germany against ships, as theUSAAFwould 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 Committeedeveloped theVB-6 Felix,which used infrared to home on ships. While it entered production in 1945, it was never employed operationally.[11]

Korean War

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The US briefly deployed theASM-A-1 Tarzon(or VB-13 Tarson) bomb (aTallboyfitted with radio guidance) during theKorean War,dropping them fromBoeing B-29 Superfortresses.

Vietnam War

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In 1962, the US Army began research intolaserguidance systems and by 1967 the USAF had conducted a competitive evaluation leading to full development of the world's firstlaser-guided bomb,theBOLT-117,in 1968.

Gulf War

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GBU-12 Paveway IIswere used to great effect in the firstGulf War,dropped fromF-111Faircraft to destroy Iraqi armored vehicles in a process referred to as "tank plinking".

War on Terror

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Lessons learned during the first Gulf War showed the value of guided bombs, with precision-guided munitions accounting for 70% of munitions expended duringOperation Enduring Freedom.[12]

Advanced guidance concepts

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Responding to after-action reports from pilots who employed laser and/or satellite guided weapons,Boeinghas developed a Laser JDAM (LJDAM) to provide both types of guidance in a single kit. Based on the existingJDAMconfigurations, 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 theIraq Warincluded a single 2,000-lb JDAM and two 500-lb LGBs. With LJDAM, and the newSmall Diameter Bomb,these same aircraft can carry more bombs if necessary, and have the option of satellite or laser guidance for each weapon release.

See also

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Notes

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  1. ^Hamilton, Richard (1995)."Precision guided munitions and the new era of warfare".Air Power Studies Centre, Royal Australian Air Force.Retrieved2009-02-02.
  2. ^"Bomb With A Brain".British Pathénewsreel 52/51A, June 23, 1952. Accessed 2013-04-04.
  3. ^Fitzsimons,op. cit.,Volume 10, p.1090, "Gargoyle".
  4. ^Fitzsimons,op. cit.,Volume 9, p.926, "Felix".
  5. ^Thanh Hoa BridgeArchived2005-11-09 at theWayback Machine
  6. ^Britain's Small WarsArchived2011-01-20 at theWayback Machine
  7. ^JDAM continues to be warfighter's weapon of choice
  8. ^U.S. Air ForceFactsheets: Joint Direct Attack Munition
  9. ^JDAM Specifications
  10. ^DCI Statement on the Belgrade Chinese EmbassyArchived2006-10-04 at theWayback Machine
  11. ^Fitzsimons,op. cit.,Volume 9, p.926, "Felix".
  12. ^Lambeth, Benjamin S. (2005)."Air Power Against Terror: America's Conduct of Operation Enduring Freedom"(PDF).RAND Corporation.Archived(PDF)from the original on 2014-10-21.
  13. ^Boeing Laser JDAMArchived2006-05-22 at theWayback Machine
  14. ^Raytheon Enhanced PavewayArchived2008-03-07 at theWayback Machine
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