Precision-guided munition


A precision-guided munition, also called a smart weapon, smart munition, or smart bomb, is a type of weapon system that integrates advanced guidance and control systems, such as GPS, laser guidance, or infrared sensors, with various types of munitions, typically missiles or artillery shells, to allow for high-accuracy strikes against designated targets. PGMs are designed to precisely hit a predetermined target, typically with a margin of error that is far smaller than conventional unguided munitions. Unlike unguided munitions, PGMs use active or passive control mechanisms capable of steering the weapon towards its intended target. PGMs are capable of mid-flight course corrections, allowing them to adjust and hit the intended target even if conditions change. PGMs can be deployed from various platforms, including aircraft, naval ships, ground vehicles, ground-based launchers, and UAVs. 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 minimize collateral damage. PGMs are considered an element of modern warfare to reduce unintended damage and civilian casualties. It is widely accepted that PGMs significantly outperform unguided weapons, particularly against fortified or mobile 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.
Because the damage effects of explosive weapons decrease with distance due to an inverse cube law, even modest improvements in accuracy 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, 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 to electronic warfare and cyberattacks.

Types

Recognizing the difficulty of hitting moving ships during the Spanish Civil War, the Germans were first to develop steerable munitions, using radio control or wire guidance. The U.S. tested TV-guided, semi-active radar-guided, and infrared-guided weapons.

Radio-controlled

The Germans were first to introduce PGMs in combat, with KG 100 deploying the MCLOS-guidance Fritz X armored glide bomb, guided by the Kehl-Straßburg radio guidance system, to successfully attack the Italian battleship Roma in 1943, and the similarly Kehl-Straßburg MCLOS-guided Henschel Hs 293 rocket-boosted glide bomb.
The closest Allied equivalents, both unpowered designs, were the VB-1 AZON, 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 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-propelled Gargoyle, which never entered service. Japanese PGMs—with the exception of the anti-ship air-launched, rocket-powered, human-piloted Yokosuka MXY-7 Ohka, "Kamikaze" flying bomb did not see combat in World War II.
Prior to the war, the British experimented with radio-controlled remotely guided planes laden with explosives, such as Larynx. The United States Army Air Forces used similar techniques with Operation Aphrodite, but had few successes; the German Mistel "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 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 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

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. The first successful electro optical guided munition was the AGM-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.
The Raytheon Maverick 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, imaging infrared, and laser homing. 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 is a drop and forget precision-guided glide bomb. The Israeli Elbit Opher 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.

Laser-guided

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.
Originally the project began as a surface to air missile seeker developed by Texas 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 and greatly exceeded the design requirements. The system was sent to Vietnam and performed well. Without the existence of targeting pods they had to be aimed using a hand held laser from the back seat of an F-4 Phantom aircraft, but still performed well. Eventually over 28,000 were dropped during the war.
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. This structure had previously been the target of 800 American sorties and was partially destroyed in each of two successful attacks, the other being on 27 April 1972 using AGM-62 Walleyes.
They were used, though not on a large scale, by the British forces during the 1982 Falklands War. 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 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.
  • Paveway is a series of laser-guided bombs made in the United States. Paveway II LGBs are a cheaper lightweight precision-guided munition suitable for use against vehicles and other small targets, while a Paveway III penetrator 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 first Gulf War, dropped from F-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 the United States Navy. The Skipper was intended as an anti-ship weapon, capable of disabling the largest vessels with a impact-fuzed warhead. It was composed of a Mark 83 bomb fitted with a Paveway 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-56 Joint Direct Attack Munitions, or "Laser JDAMs", which add a laser seeker to the nose of a JDAM-equipped bomb, enabling it to engage moving targets. The laser seeker is a cooperative development between Boeing's Defense, Space and Security unit and Israel's Elbit Systems.
  • Sudarshan is an Indian laser-guided bomb kit, developed by Aeronautical Development Establishment, a DRDO lab with technological support from another DRDO lab Instruments Research and Development Establishment, for the Indian Air Force.
  • 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 also known as Laser, infrared Guided Rocket is a design conversion of Hydra 70 unguided rockets with a laser guidance kit to turn them into precision-guided munitions.
  • Ugroza 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. 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.
  • The Roketsan Cirit is a Turkish semi-active laser laser guided missile.
  • 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 "dumb fire" gravity bombs, making them into laser-guided smart bombs. Initial development completed in 1990.