"Smart Weapon" redirects here. For the weapon systems customized to a single
person, see personalized gun. A precision-guided munition is a guided
munition intended to precisely hit a specific target, and to minimize
collateral damage. 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 bombs
"unguided bombs", "dumb bombs", or "iron bombs".
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 weapons = The Germans were first to introduce PGMs
in combat, with the 1,400-kg MCLOS-guidance Fritz X armored gravity
ordnance, to successfully attack the Italian battleship Roma in 1943 and sink
a hospital ship at Anzio, and the similarly MCLOS-guided Henschel Hs 293
rocket-boosted glide missile. The closest Allied equivalents were the
1,000-lb 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
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 Ohka suicide 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
explosive, 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
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. 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, imaging
infra-red, 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
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. = Laser-guided weapons =
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 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 Hoa 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 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. 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 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 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 are
a cheaper lightweight PGM suitable for use against vehicles and other small
targets, while a Paveway III 2,000-pound penetrator 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."
= Radar = 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 =
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. The problem of poor visibility does not affect satellite-guided weapons
such as Joint Direct Attack Munition and Joint Stand-Off Weapon, 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 of 13
m under GPS guidance, but typically only 30 m under inertial 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 accidental United States bombing of the Chinese embassy in
Belgrade during Operation Allied Force by NATO aircraft was attributed to
faulty target information. 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 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. Raytheon has developed the Enhanced Paveway
family, which adds GPS/INS guidance to their Paveway family of laser-guidance
packages. 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 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. = Cannon-launched guided projectiles =
A cannon-launched guided projectile, 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 and a
program to mate a Paveway guidance system to an 8" shell for the 8"/55
caliber Mark 71 gun in the 1970s. 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. = 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. 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. See also
AASM Cruise missile
Circular error probable Cannon-launched guided projectile
GB-4 GB-8
GBU-15 GBU-28
GBU-39 Small Diameter Bomb GBU-57 Massive Ordnance Penetrator
Barq H-4 MUPSOW
H-2 MUPSOW HOPE/HOSBO
Joint Direct Attack Munition M712 Copperhead
McDonnell LBD Gargoyle MGM-51 Shillelagh
Missile guidance Point target
Range Extension Kit(REK) by Global Industrial Defence Solutions
SOM Spice
Strix mortar round VB-6 Felix
Wire-guided missile Small Diameter Bomb
Notes External links
A Brief History of Precision Guided Weapons
How Smart Bombs Work BBC: "Smart bombs missed Iraqi targets"
— on the first employment of the JSOW, guidance failures from a software error
subsequently fixed. "Fact File: Smart Bombs - not so Smart"
BBC story discussing the limitations of guided munition employment.
Janes.com: "Ukraine develops indigenous guided airborne weapons" — 2006 article
about Ukrainian guided bomb development. "World War II Glide Bombs"
"World War II Glide Bombs" "World War II Glide Bombs"
"Soviet/Russian Guided Bombs" by Air Power Australia
Induction Rocket Systems "TELSON" with "Aculeus" laser-guided rocket by TDA
ARMEMENTS SAS. Induction Rockets Systems About the
induction rockets that arm the attack helicopter Tiger