Precision-guided munition

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BOLT-117, the world's first laser-guided bomb

A precision-guided munition (PGM, smart weapon, smart munition, smart bomb) is a guided munition intended to precisely hit a specific target, to minimize collateral damage and increase lethality against intended targets.[1]

Because the damage effects of explosive weapons decrease with distance due to an inverse cube law, even modest improvements in accuracy (hence reduction in miss distance) enable a target to be attacked with fewer or smaller bombs. Thus, even if some guided bombs miss, fewer air crews are put at risk and the harm to civilians and the amount of collateral damage may be reduced.

The advent of precision-guided munitions resulted in the renaming of older bombs "unguided bombs", "dumb bombs", or "iron bombs".


A laser-guided GBU-24 (BLU-109 warhead variant) strikes its target.

Recognizing the difficulty of hitting moving ships during the Spanish Civil War,[2] the Germans were first to develop steerable munitions, using radio control or wire guidance. The U.S. tested TV-guided (GB-4),[3] semi-active radar-guided (Bat), and infrared-guided (Felix) weapons.

Radio-controlled weapons

The Germans were first to introduce PGMs in combat, with KG 100 deploying the 1,400-kg (3,100-lb) MCLOS-guidance Fritz X armored gravity ordnance, to successfully attack the Italian battleship Roma in 1943 and sink a hospital ship at Anzio[citation needed], and the similarly MCLOS-guided Henschel Hs 293 rocket-boosted glide missile (also in use since 1943, but only against lightly armored or unarmored ship targets). The closest Allied equivalents were the 1,000-lb (454-kg) VB-1 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—the Navy's Bat had its own on board, autonomous radar seeker system to direct it to a target. In addition, the U.S. tested the rocket-propelled Gargoyle, which never entered service.[4] Japanese PGMs—with the exception of the anti-ship air-launched, rocket-powered, human-piloted Ohka suicide flying bomb—did not see combat in World War II.[5]

Prior to the war, the British experimented with radio-controlled remotely guided planes laden with explosive, such as Larynx. 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, guided by the human pilot flying the single-engined fighter mounted above the unmanned, explosive-laden twin engined "flying bomb" below it, released in the Mistel's attack dive from the fighter.

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 iron 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.

Infrared-guided/electro-optical weapons

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.[6] Precision guidance has been applied to weapons other than conventional bomb warheads. The Raytheon Maverick heavy anti-tank missile has among its various marks guidance systems such as electro-optical (AGM-65A), imaging infra-red (AGM-65D), and laser homing (AGM-65E).[7] The first two, by guiding themselves based on the visual or IR scene of the target, are fire-and-forget in that the pilot can release the weapon and it will guide itself to the target without further input, which allows the delivery aircraft to manoeuvre to escape return fire. The Pakistani NESCOM H-2 MUPSOW and H-4 MUPSOW is an electro-optical (I.R imaging and Television guided) is a drop and forget precision-guided glide bomb. The Israeli Elbit Opher is also an I.R imaging "drop and forget" guided bomb that has been reported to be considerably cheaper than laser-homing bombs and can be used by any aircraft, not requiring specialized wiring for a laser designator or for another aircraft to illuminate the target. During NATO's air campaign in 1999 in Kosovo the new Italian AF AMX employed the Opher.[8]

Laser-guided weapons

Diagram showing the operation of a laser-guided ammunition round. From a CIA report, 1986.

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 a target designator cannot get near the target. The laser designator sends its beam in a coded series of 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 they were used in the second successful attack on the Thanh Hóa Bridge ("Dragon's Jaw"). This structure had previously been the target of 800 American sorties[9] (using unguided weapons) and was partially destroyed in each of two successful attacks, the other being on 27 April 1972 using Walleyes.

They were used, though not on a large scale, by the British forces during the 1982 Falklands War.[10] The first large-scale use of smart weapons came in the early 1990s 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 2,000-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."

AGM-123 Skipper II is a short-range laser-guided missile developed by the United States Navy. The Skipper was intended as an anti-ship weapon, capable of disabling the largest vessels with a 1,000-lb (450-kg) impact-fuzed warhead. It is composed of a Mark 83 bomb fitted with a Paveway guidance kit and two Mk 78 solid propellant rockets that fire upon launch.

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),[11][12] for the Indian Air Force (IAF).[13][14][15]

KAB-1500L and KAB-500L are Russian laser-guided bombs.

LT PGB is a family of Chinese laser-guided munitions.

LS PGB is a family of Chinese GPS+INS or laser guided munitions.

The Advanced Precision Kill Weapon System (APKWS) also known as Laser, infrared Guided Rocket (LiGR) is a design conversion of Hydra 70 unguided rockets with a laser guidance kit to turn them into precision-guided munitions (PGMs).[16][17][18]

Ugroza (Russian: Угроза, meaning "menace") is a precision-guided weapons system made in Russian Federation. It is an upgrade for standard Russian "dumb" rockets, including the S-5, S-8, and S-13 rockets.[19][20] The system upgrades the "dumb" rockets with laser guidance, very significantly increasing their accuracy. It requires a laser target designator, from either an airborne or land based source, to "paint" a target. Circular error probable (CEP) is about 0.8 to 1.8 m,[19] while maximum ranges of rockets varies from the rockets used 1.5–8 km.[19] Ugroza allows rockets to be ripple-fired up to 7 at a time. The notable novelty is that the system does not use aerodynamic flight control (e.g. tail fins), but impulse steering with mini-thrusters.[19] It has been dubbed as the Russian concept of impulse corrections (RCIC).[19]


The Lockheed-Martin Hellfire II light-weight anti-tank weapon in one mark uses the radar on the Boeing AH-64D Apache Longbow to provide fire-and-forget guidance for that weapon.

Satellite-guided weapons

A F-22 releases a JDAM from its center internal bay while flying at supersonic speed
HOPE/HOSBO of the Luftwaffe with a combination of GPS/INS and electro-optical guidance

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.[21] 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).[22][23]

Wan chien - Taiwanese indigenous version of JDAM.[24]

The Griffin Laser Guided Bomb (Griffin LGB) 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 "dumb fire" gravity bombs, making them into laser-guided smart bombs (with the option of GPS guidance). Initial development completed in 1990. The Griffin conversion kit consists of a front "seeker" section and a set of steerable tailplanes. The resulting guided munition features "trajectory shaping", which allows the bomb to fall along a variety of trajectories – from a shallow angle to a vertical top attack profile. IAI publishes a circular error probable figure for the weapon of 5 metres.[25]

The 'GBU-57A/B Massive Ordnance Penetrator (MOP) is a U.S. Air Force, precision-guided, 30,000-pound (14,000 kg) "bunker buster" bomb.[26] This is substantially larger than the deepest penetrating bunker busters previously available, the 5,000-pound (2,300 kg) GBU-28 and GBU-37.

The SMKB (Smart-MK-Bomb) is a Brazilian guidance kit that turns a standard Mk 82 (500 lbs) and Mk 83 (1.000 lbs) into a Precision-guided weapon, respectively called SMKB-82 and SMKB-83. The kit provides extended range up to 50 kilometres (27 nmi) and are guided by an integrated inertial guidance system coupled to three satellites networks, relying on wireless to handle the flow of data between the aircraft and the munition.

FT PGB is a family of Chinese satellite and Inertial, guided munitions.

LS PGB is a family of Chinese GPS+INS or laser guided munitions.

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 United States bombing of the Chinese embassy in Belgrade during Operation Allied Force by NATO aircraft was attributed to faulty target information.[27] 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.

Advanced guidance concepts

Responding to after-action reports from pilots who employed laser or satellite guided weapons, Boeing developed a Laser JDAM (LJDAM) to provide both types of guidance in a single kit. Based on the existing Joint Direct Attack Munition configurations, a laser guidance package is added to a GPS/INS-guided weapon to increase its overall accuracy.[28] Raytheon has developed the Enhanced Paveway family, which adds GPS/INS guidance to their Paveway family of laser-guidance packages.[29] 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 1,000-lb LGBs. With LJDAM, and the new GBU-39 Small Diameter Bomb (SDB), these same aircraft can carry more bombs if necessary, and have the option of satellite or laser guidance for each weapon release.

Spice (munition) is an Israeli EO/GPS-guided guidance kit for converting air-droppable unguided bombs into precision guided bombs. Spice can be preprogrammed, with up to 100 different targets it may have to engage during a mission. The one target it will actually engage may then be selected, inflight, by an aircrewman.

The HGK guidance kit (HGK), Turkish: Hassas Güdüm Kiti / Precision Guidance Kit), developed by TÜBİTAK-SAGE, is a GPS/INS guidance kit that converts 2000-lb Mark 84 bombs into smart weapons. It enables precision strike capability in all weather conditions with long range at a dispersion of 6 m (20 ft).[30]

Armement Air-Sol Modulaire (AASM)[31][32] is a French equivalent to JDAM. AASM comprises a frontal guidance kit and a rear-mounted range extension kit matched to a dumb bomb. The weapon is modular because it can integrate different types of guidance units and different types of bombs. It uses hybrid inertial navigation system (INS) / Global Positioning System (GPS) guidance. Other variants add infrared homing or laser guidance to increase accuracy.

Paveway IV is a dual mode GPS/INS and laser-guided bomb manufactured by Raytheon UK (formerly Raytheon Systems Limited).[33] It is the latest iteration of the Paveway series.

DRDO Smart Anti-Airfield Weapon is an Indian precision-guided guided Anti-Airfield Weapon with the range up to 100 km.

Cannon and mortar-launched guided projectiles

A cannon-launched guided projectile (CLGP), a precursor to modern PGMs, is fired from artillery, ship's cannon, or armored vehicles. Several agencies and organizations sponsored the CLGP programs. The United States Navy sponsored the Deadeye program, a laser-guided shell for its 5" guns[34] and a program to mate a Paveway guidance system to an 8" shell[35] for the 8"/55 caliber Mark 71 gun in the 1970s (Photo). Other Navy efforts include the BTERM, ERGM, and LRLAP shells.

The U.S. Army's MGM-51 Shillelagh missile can be considered a type of CLGP. Intended for use on the M551 Sheridan light tank, the Shillelagh missile was fired out of the Sheridan's cannon to provide robust anti-tank capability. The Army's M712 Copperhead laser guided artillery round was used in Desert Storm. Army CLGPs include the M982 Excalibur 155mm artillery shell, the XM395 Precision Guided Mortar Munition, and the XM1156 Precision Guidance Kit to refit existing 155mm shells with precision guidance, as the Air Force's JDAM program converts dumb bombs into precision munitions.

30F39 Krasnopol is a Russian 152/155 mm cannon-launched, fin-stabilized, base bleed-assisted, semi-automatic laser-guided, explosive projectile. It automatically 'homes' on a point illuminated by a laser designator, typically operated by a ground-based artillery observer.

Pansarsprängvinggranat m/94 STRIX is a Swedish endphase-guided projectile fired from a 120 mm mortar currently manufactured by Saab Bofors Dynamics. STRIX is fired like a conventional mortar round. The round contains an infrared imaging sensor that it uses to guide itself onto any tank or armoured fighting vehicle in the vicinity where it lands. The seeker is designed to ignore targets that are already burning.

Basir is an Iranian artillery fired laser-guided, 155 mm explosive projectile designed to destroy enemy tanks, vehicles and other moving or non-moving targets with high precision.[36] This weapon is similar in function with Russian Kransnopol or American M712 Copperhead. Basir put Iran among the five countries in the world with laser targeting technology.[37]

SMArt 155 is a German 155 mm artillery round, designed for a long range, indirect fire top attack role against armoured vehicles. The SMArt carrier shell contains two submunitions with infrared sensor and millimeter wave radar, which descend over the battlefield on ballutes and attack hardened targets with explosively formed penetrator warheads. Built with multiple redundant self-destruct mechanisms, these submunitions were specifically designed[dubious ] to fall outside the category of submunition weapons prohibited by the 2008 Convention on Cluster Munitions.

Guided small arms

Precision-guided small arms prototypes have been developed which use a laser designator to guide an electronically actuated bullet to a target.[38] Another system in development uses a laser range finder to trigger an explosive small arms shell in proximity to a target. The U.S. Army plans to use such devices in the future.[39]

See also


  1. Hamilton, Richard (1995). "Precision guided munitions and the new era of warefare". Air Power Studies Centre, Royal Australian Air Force. Retrieved 2009-02-02.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  2. Fitzsimons, Bernard, editor. The Illustrated Encyclopedia of 20th Century Weapons and Warfare (London: Phoebus, 1978), Volume 10, p.1037, "Fritz-X".
  3. Fitzsimons, op. cit., Volume 10, p.1101, "GB-4".
  4. Fitzsimons, op. cit., Volume 10, p. 1090, "Gargoyle".
  5. Martin Caidin (1956). "Japanese Guided Missiles in World War II". Journal of Jet Propulsion. 26 (8): 691–694.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  6. Fitzsimons, op. cit., Volume 9, p. 926, "Felix".
  7. Raytheon AGM-65 Maverick
  8. "Opher bomb deployed in Kosovo" FLIGHT Daily News, 17 June 1999
  9. Thanh Hoa Bridge
  10. Britain's Small Wars
  11. Dehradun, Oct 20 (PTI). "India develops first Laser Guided Bomb". Retrieved 2012-02-19.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  12. Nitsi (2010-10-21). "India invents 1st Laser Guided Bomb". Retrieved 2012-02-19.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  13. "India conducts flight trials of laser-guided bombs". 2010-01-21. Retrieved 2012-02-19.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  14. India develops first laser guided bomb, MSN News<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  15. "India successfully develops advanced laser guided bomb". 2010-10-20. Retrieved 2012-02-19.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  17. U.S. Army Plans First Deployment of Laser-Guided Rocket -, 14 October 2015
  19. 19.0 19.1 19.2 19.3 19.4 Cite error: Invalid <ref> tag; no text was provided for refs named nvo
  20. Cite error: Invalid <ref> tag; no text was provided for refs named nf
  21. JDAM continues to be warfighter's weapon of choice
  22. U.S. Air Force Factsheets: Joint Direct Attack Munition
  23. John Pike. "Joint Direct Attack Munition (JDAM)". Retrieved 1 April 2015.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  24. "Taiwan develops 'anti-invasion' munitions against China". Fox News. 2013-09-21. Retrieved 2017-03-09.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  25. "Laser-Guided Bomb Kits". Israel Aerospace Industries. Retrieved 20 February 2013.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  26. B-2/Massive Ordnance Penetrator (MOP) GBU-57A/B. FedBizOpps
  27. DCI Statement on the Belgrade Chinese Embassy
  28. "Weapons" (PDF). Retrieved 1 April 2015.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  29. Raytheon Enhanced Paveway
  33. "Paveway IV". Royal Air Force. Retrieved 7 January 2015.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  34. "USA 5"/54 (12.7 cm) Mark 42". Retrieved 1 April 2015.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  35. "USA 8"/55 (20.3 cm) Mark 71". Retrieved 1 April 2015.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  36. Mashregh news
  38. "Sandia's self-guided bullet prototype can hit target a mile away".<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  39. Kleiner, Kurt (2009-06-06). "Radio-controlled bullets leave no place to hide". New Scientist. Retrieved 2009-06-14.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>

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