Aprecision-guided munition (PGM), also called asmart weapon,smart munition, orsmart bomb, is a type ofweapon system that integrates advanced guidance and control systems, such asGPS,laser guidance, orinfrared sensors, with various types ofmunitions, typicallymissiles orartillery shells, to allow for high-accuracy strikes against designatedtargets.[1][2] PGMs are designed to precisely hit a predetermined target, typically with a margin of error (orcircular error probable, CEP) that is far smaller than conventional unguided munitions.[3][4] Unlike unguided munitions, PGMs use active or passivecontrol mechanisms capable of steering the weapon towards its intended target.[5][6] PGMs are capable of mid-flight course corrections, allowing them to adjust and hit the intended target even if conditions change.[1][7] PGMs can be deployed from various platforms, including aircraft, naval ships, ground vehicles, ground-based launchers, andUAVs.[2][3] PGMs are primarily used in military operations to achieve greater accuracy, particularly in complex or sensitive environments, to reduce the risk to operators, lessen civilian harm, and minimizecollateral damage.[8][1] PGMs are considered an element of modern warfare to reduce unintended damage and civilian casualties.[9][5] It is widely accepted that PGMs significantly outperform unguided weapons, particularly against fortified or mobile targets.[3][7]
During thePersian 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.[10]
Because the damage effects ofexplosive 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 someguided bombs miss, fewer air crews are put at risk and the harm to civilians and the amount of collateral damage may be reduced.[a][b]
The advent of precision-guided munitions resulted in the renaming of older, low-technology bombs as "unguided bombs", "dumb bombs", or "iron bombs".
Some challenges of precision-guided munitions include high development and production costs and the reliance of PGMs on advanced technologies like GPS make them vulnerable toelectronic warfare andcyberattacks.[17]
The Germans were first to introduce PGMs in combat, withKG 100 deploying the 3,100 lb (1,400 kg)MCLOS-guidanceFritz X armoredglide bomb, guided by theKehl-Straßburg radio guidance system, to successfully attack the ItalianbattleshipRoma in 1943,[20] and the similarlyKehl-Straßburg MCLOS-guidedHenschel Hs 293 rocket-boosted glide bomb (also in use since 1943, but only against lightly armored or unarmored ship targets).
The closestAllied equivalents, both unpowered designs, were the 1,000 lb (450 kg) VB-1AZON (from "AZimuth ONly" control), used in both Europe and theCBI theater, and theUS Navy'sBat, primarily used in the Pacific Theater of World War II — the Navy's Bat was more advanced than either German PGM ordnance design or the USAAF's VB-1 AZON, in that it had its own on board,autonomous radar seeker system to direct it to a target. In addition, the U.S. tested the rocket-propelledGargoyle, which never entered service.[21] Japanese PGMs—with the exception of theanti-ship air-launched, rocket-powered, human-pilotedYokosuka MXY-7 Ohka, "Kamikaze" flying bomb did not see combat in World War II.[22]
Prior to the war, the British experimented with radio-controlled remotely guided planes laden with explosives, such asLarynx. TheUnited States Army Air Forces used similar techniques withOperation Aphrodite, but had few successes; the GermanMistel (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 theMistel's attack dive from the fighter.
The U.S. programs restarted in theKorean War. In the 1960s, theelectro-optical bomb (orcamera bomb) was reintroduced. They were equipped withtelevision 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 theUSAF in the last few years of theVietnam 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; theThanh Hoa Bridge, for instance, was attacked repeatedly with iron bombs, to no effect, only to be dropped in one mission with PGMs.
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.[23] The first successful electro optical guided munition was theAGM-62 Walleye during the Vietnam war. It was a family of large glide bombs which could automatically track targets using contrast differences in the video feed. The original concept was created by engineer Norman Kay while tinkering with televisions as a hobby. It was based on a device which could track objects on a television screen and place a "blip" on them to indicate where it was aiming. The first test of the weapon on 29 January 1963 was a success, with the weapon making a direct hit on the target. It served successfully for three decades until the 1990s.[24][25]
TheRaytheonMaverick is the most common electro optical guided missile. As a heavy anti-tank missile it has among its various marks guidance systems such as electro-optical (AGM-65A), imaging infrared (AGM-65D), and laser homing (AGM-65E).[26] The first two, by guiding themselves based on the visual or IR scene of the target, arefire-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 PakistaniNESCOMH-2 MUPSOW andH-4 MUPSOW is an electro-optical (IR imaging and television guided) is a drop and forget precision-guided glide bomb. The Israeli ElbitOpher is also an IR 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.[27]
In 1962, the US Army began research intolaser guidance 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 alaser 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.
Originally the project began as a surface to air missile seeker developed byTexas Instruments. When Texas Instruments executive Glenn E. Penisten attempted to sell the new technology to the Air Force they inquired if it could instead be used as a ground attack system to overcome problems they were having with accuracy of bombing in Vietnam. After 6 attempts the weapon improved accuracy from 148 to 10 ft (50 to 3 m) and greatly exceeded the design requirements. The system was sent to Vietnam and performed well. Without the existence oftargeting pods they had to be aimed using a hand held laser from the back seat of anF-4 Phantom aircraft, but still performed well. Eventually over 28,000 were dropped during the war.[10]
Diagram showing the operation of a laser-guided ammunition round. From a CIA report, 1986.
Laser-guided weapons did not become commonplace until the advent of themicrochip. They made their practical debut in Vietnam, where on 13 May 1972 they were used in the second successful attack on theThanh Hóa Bridge ("Dragon's Jaw"). This structure had previously been the target of 800 American sorties[28] (using unguided weapons) and was partially destroyed in each of two successful attacks, the other being on 27 April 1972 usingAGM-62 Walleyes.
They were used, though not on a large scale, by the British forces during the 1982Falklands War.[29] The first large-scale use of smart weapons came in the early 1990s during OperationDesert Storm when 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.
Paveway is a series of laser-guided bombs made in the United States. Paveway II 500 lb (230 kg) LGBs (such asGBU-12) are a cheaper lightweight precision-guided munition (PGM) suitable for use against vehicles and other small targets, while a Paveway III 2,000 lb (910 kg) penetrator (such asGBU-24) is a more expensive weapon with improved aerodynamic efficiency suitable for use against high-value targets. GBU-12s were used to great effect in the firstGulf War, dropped fromF-111F aircraft to destroy Iraqi armored vehicles in a process informally referred to by pilots as "tank plinking."
AGM-123 Skipper II was a short-range laser-guided missile developed by theUnited States Navy. The Skipper was intended as ananti-ship weapon, capable of disabling the largest vessels with a 1,000 lb (450 kg) impact-fuzed warhead. It was composed of aMark 83 bomb fitted with aPaveway guidance kit and two Mk 78 solid propellant rockets that fire upon launch.
Some of the most commonly used laser-guided bombs are the family of GBU-54, GBU-55, and GBU-56Joint Direct Attack Munitions, or "Laser JDAMs" (LJDAMs), which add alaser seeker to the nose of a JDAM-equipped bomb, enabling it to engage moving targets. The laser seeker is a cooperative development betweenBoeing's Defense, Space and Security unit and Israel'sElbit Systems.[30]
Ugroza (Russian:Угроза, meaning "menace") is a precision-guided weapons system made inRussian Federation. It is an upgrade for standard Russian "dumb" rockets, including theS-5,S-8, andS-13 rockets.[39][40] The system upgrades the "dumb" rockets withlaser guidance, very significantly increasing their accuracy. It requires alaser target designator, from either an airborne or land based source, to "paint" a target.
The Lockheed-MartinHellfire II light-weight anti-tank weapon in one mark uses the radar on theBoeingAH-64D Apache Longbow to provide fire-and-forget guidance for that weapon.
AF-22 releases aJDAM from its center internal bay while flying at supersonic speed.HOPE/HOSBO of theLuftwaffe 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.[43] 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'GPS system for guidance. This weapon can be employed in all weather conditions, without any need for ground support. Because it is possible tojam GPS, the guidance package reverts toinertial navigation in the event of GPS signal loss. Inertial navigation is significantly less accurate; the JDAM achieves a publishedCircular Error Probable (CEP) of 43 ft (13 m) under GPS guidance, but typically only 98 ft (30 m) under inertial guidance (with free fall times of 100 seconds or less).[44][45]
TheJoint Direct Attack Munition (JDAM) is a guidance kit that convertsunguided bombs, or "dumb bombs", into all-weather "smart" munitions. JDAM-equipped bombs are guided by an integratedinertial guidance system coupled to aGlobal Positioning System (GPS) receiver, giving them a published range of up to 17 mi (28 km). JDAM-equipped bombs range from 500 to 2,000 pounds (230 to 910 kg).[46] When installed on a bomb, the JDAM kit is given a GBU (Guided Bomb Unit) nomenclature, superseding theMark 80 orBLU (Bomb, Live Unit) nomenclature of the bomb to which it is attached.
Wind Corrected Munitions Dispenser (WCMD) is aGPS/INS-guided US tail kit for use with the TMD (Tactical Munitions Dispenser) family of cluster bombs to convert them to precision-guided munitions.
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 verticaltop attack profile. IAI publishes acircular error probable figure for the weapon of 5 metres.[50]
TheGBU-57A/BMassiveOrdnance Penetrator (MOP) is aU.S. Air Force, precision-guided, 30,000-pound (14,000 kg) "bunker buster"bomb.[51] This is substantially larger than the deepest penetrating bunker busters previously available, the 5,000-pound (2,300 kg)GBU-28 andGBU-37.
TheSMKB (Smart-MK-Bomb) is a Brazilian guidance kit that turns a standard 500-pound (230 kg)Mk 82 or 1,000-pound (450 kg)Mk 83 into a precision-guided weapon, respectively called SMKB-82 and SMKB-83. The kit provides extended range up to 31 mi (50 km) and are guided by an integratedinertial guidance system coupled to three satellites networks (GPS,Galileo andGLONASS), relying on wireless to handle the flow of data between the aircraft and the munition.
FT PGB is a family of Chinese satellite andInertial, 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 accidentalUnited States bombing of the Chinese embassy in Belgrade duringOperation Allied Force by NATO aircraft was attributed to faulty target information.[52] However, if the targeting informationis 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.
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 existingJoint Direct Attack Munition configurations, a laser guidance package is added to a GPS/INS-guided weapon to increase its overall accuracy.[53] Raytheon has developed the Enhanced Paveway family, which adds GPS/INS guidance to their Paveway family of laser-guidance packages.[54] 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 War included a single 2,000-pound (910 kg) JDAM and two 1,000-pound (450 kg) LGBs. With LJDAM, and the new GBU-39Small 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 IsraeliEO/GPS-guided guidance kit for converting air-droppable unguidedbombs 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 willactually engage may then be selected, inflight, by an aircrewman.
The U.S. Navy leads development for a new 155 mm (6.1 in) artillery round called Moving Target Artillery Round, capable of destroying moving targets in GPS-denied environments". The Office of Naval Research (ONR), the Naval Surface Warfare Center Dahlgren Division (NSWC Dahlgren), and theU.S. Army Research Laboratory (ARL) have been coordinating MTAR, with final development scheduled for 2019.[60]
Key features of the MTAR shell include extended range against moving targets, precision guidance and navigation without GPS, subsystem modularity, subsystem maturity, weapon system compatibility, restricted altitude, all-weather capability, reduced time of flight, and affordability. The new munition is intended for the Army or Marine Corps M777A1 howitzer, the M109A6 Paladin, and M109A7 Paladin Integrated Management (PIM) self-propelled 155 mm (6.1 in) artillery systems. The shell also would be for the Navy's Advanced Gun System (AGS) aboard the Zumwalt-class destroyer, and other future naval gun systems.[61]
Precision Guidance Kit – Modernization (PGK-M)
The U.S. Army is planning for GPS-denied environments with the new Precision Guidance Kit – Modernization (PGK-M). An enhancement of previous technologies, PGK-M will give U.S. forces the ability to continue launching precision strikes when GPS is compromised by the enemy.[62]
Picatinny Arsenal engineers are leading the development of a GPS alternative using image navigation for precision guidance of munitions, under the Armament Research, Development and Engineering Center (ARDEC). Other research partners include Draper Labs,U.S. Army Research Laboratory,Air Force Research Laboratory and the Aviation and Missile Research, Development, and Engineering Center.[63]
The enhanced munition can navigate to a desired location, through a reference image used by the technology to reach the target.[63] The PGK-M includes a collection of ad hoc software programmable radio networks, various kinds of wave-relay connectivity technologies and navigational technology.[62]
PBK-500U Drel is a Russian guided jamming-resistant stealth glide bomb.
M982 Excalibur, GPS-guided munitions (XM982) for 155 mm artillery was developed in a collaborative effort betweenU.S. Army Research Laboratory (ARL) and the Armaments Research and Development Center (ARDEC). Research included developing GPS and microelectromechanical systems (MEMS) Inertial Sensor Technology. Excalibur was fielded in Operation Iraqi Freedom in the summer of 2007. Technology developed on the Excalibur is also applied in the Army's Precision Guidance Kit (PGK) for use on existing conventional projectiles and the Mortar Guidance Kit (MGK) for use on conventional mortars.[66]
30F39 Krasnopol is a Russian 152 / 155 mm (6.0 / 6.1 in)cannon-launched, fin-stabilized,base bleed-assisted, semi-automaticlaser-guided,explosiveprojectile. It automatically 'homes' on a point illuminated by a laser designator, typically operated by a ground-based artillery observer.
STRIX is fired like a conventional mortar round. The round contains aninfrared imaging sensor that it uses to guide itself onto anytank orarmoured fighting vehicle in the vicinity where it lands. The seeker is designed to ignore targets that are already burning.[69]
Precision-guidedsmall arms prototypes have been developed which use a laser designator to guide anelectronically actuated bullet to a target.[82] 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.[83]
In 2008 theEXACTO program began underDARPA to develop a "fire and forget" smart sniper rifle system including a guided smart bullet and improved scope. The exact technologies of this smart bullet have not been released. EXACTO was test fired in 2014 and 2015 and results showing the bullet altered course to correct its path to its target were released.[84]
In 2012Sandia National Laboratories announced a self-guided bullet prototype that could track a target illuminated with alaser designator. The bullet is capable of updating its position 30 times a second and hitting targets over a mile away.[85]
In mid-2016, Russia revealed it was developing a similar "smart bullet" weapon designed to hit targets at a distance of up to 6 mi (10 km).[86][87]
Pike[88] is a precision-guided mini-missile fired from an underslung grenade launcher.
Air burst grenade launchers are a type of precision-guided weapons. Such grenade launchers can preprogram their grenades using afire-control system to explode in the air above or beside the enemy.[89][90][91]
Precision-guided munitions (PGMs) with multiple modeguidance systems[92][93] use multiple targeting technologies to enhance accuracy and adaptability.[94] The multiple guidance systems merge long-range precision, mid-course correction, and final-phase strike accuracy using a combination of guidance technologies such asGPS,inertial navigation systems (INS),[95]laser,infrared (IR),radar andartificial intelligence (AI).[96][97][98][94] Multiple mode guidance systems address the limitations of single-mode guidance, such as adverse weather, challenging terrain, blocked GPS signals, and enemycountermeasures, to ensure effective operation.[1][2] Their adaptability ensures that PGMs can still hit their target, even when one component of the system has been compromised.[4] Types of guidance used in Multiple Mode Guidance System PGMs include Global Positioning System (GPS) that give precise geolocation and long-range targeting capabilities crucial for accurate initial targeting using external satellite signals, Inertial Navigation Systems (INS) that independently tracks the munition's position usinggyroscopes andaccelerometers, Laser Guidance using directlaser beam for target guidance, Infrared (IR) Guidance sensors that detect and trackheat signatures (heat emitted by vehicles, people, or equipment), Radar Guidance fortargeting and tracking and Artificial Intelligence (AI)[99] for real-time sensor data analysis,target recognition, and decision-making.
^"During Russia's participation in the Syrian Civil War, only one of its aircraft, the Su-34 fighter-bomber, regularly used precision-guided munitions, Bronk explained, and even that aircraft often used unguided bombs and rockets.".[11]
^Connectivity toGLONASS may be a factor in the lack of Russian PGM availability,[12] and the use of 3G/4G cell towers for Russian encrypted communications (Era)[13] during the2022 Russian invasion of Ukraine. This weakness was unearthed during the use of open communication ("Russian commanders are sometimes piggybacking on Ukrainian cell phone networks to communicate")[14] when FSB was discussing the deaths of their generals: Vitaly Gerasimov, killed 7 Mar 2022;[15]Andrei Sukhovetsky, killed 28 Feb 2022.[16][12]
^MEHUL SRIVASTAVA, MADHUMITA MURGIA, AND HANNAH MURPHY, FT (3/9/2022, 8:33 AM)The secret US mission to bolster Ukraine's cyber defences ahead of Russia's invasion European official: "instead of communicating solely through encrypted military-grade phones, Russian commanders are sometimes piggybacking on Ukrainian cell phone networks to communicate, at times simply by using their Russian cell phones.'The Ukrainians love it—there is so much data in simply watching these phones, whether or not they are using encrypted apps,' he said.The Ukrainians then block Russian phones from their local networks at key moments, further jamming their communications. 'Then you suddenly see Russian soldiers grabbing cell phones off Ukrainians on the street, raiding repair shops for sims,' he said. 'This is not sophisticated stuff. It's quite puzzling."
^Fioravanzo, Giuseppe (1971).La Marina italiana nella seconda guerra mondiale – Volume XV – La Marina dall'8 settembre 1943 alla fine del conflitto [The Italian Navy in the Second World War – Volume XV – The Navy from 8 September 1943 to the End of the Conflict] (in Italian). Rome: Italian Navy Historical Branch. pp. 8–34.
^Fitzsimons,op. cit., Volume 10, p. 1090, "Gargoyle".
^Martin Caidin (1956). "Japanese Guided Missiles in World War II".Journal of Jet Propulsion.26 (8):691–694.doi:10.2514/8.7117.
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