AIM-7 Sparrow
Overview
 
The AIM-7 Sparrow is an American, medium-range semi-active radar homing
Semi-active radar homing
Semi-active radar homing, or SARH, is a common type of missile guidance system, perhaps the most common type for longer-range air-to-air and surface-to-air missile systems. The name refers to the fact that the missile itself is only a passive detector of a radar signal – provided by an external ...

 air-to-air missile
Air-to-air missile
An air-to-air missile is a missile fired from an aircraft for the purpose of destroying another aircraft. AAMs are typically powered by one or more rocket motors, usually solid fuelled but sometimes liquid fuelled...

 operated by the United States Air Force
United States Air Force
The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...

, United States Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...

 and United States Marine Corps
United States Marine Corps
The United States Marine Corps is a branch of the United States Armed Forces responsible for providing power projection from the sea, using the mobility of the United States Navy to deliver combined-arms task forces rapidly. It is one of seven uniformed services of the United States...

, as well as various allied air forces and navies. Sparrow and its derivatives were the West's principal beyond visual range (BVR) air-to-air missile from the late 1950s until the 1990s. It remains in service, although it is being phased out in aviation applications in favor of the more advanced AIM-120 AMRAAM
AIM-120 AMRAAM
The AIM-120 Advanced Medium-Range Air-to-Air Missile, or AMRAAM , is a modern beyond-visual-range air-to-air missile capable of all-weather day-and-night operations. Designed with the same form-factor as the previous generation of semi-active guided Sparrow missiles, it is a fire-and-forget...

. The Self-Defence Forces of Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

 also employ the Sparrow missile, though it is being phased out and replaced by the Mitsubishi AAM-4
Mitsubishi AAM-4
The Mitsubishi AAM-4 is a medium-range active radar-guided air-to-air missile developed in Japan and intended to replace the semi-active radar homing AIM-7 Sparrow missile in service...

.
Encyclopedia
The AIM-7 Sparrow is an American, medium-range semi-active radar homing
Semi-active radar homing
Semi-active radar homing, or SARH, is a common type of missile guidance system, perhaps the most common type for longer-range air-to-air and surface-to-air missile systems. The name refers to the fact that the missile itself is only a passive detector of a radar signal – provided by an external ...

 air-to-air missile
Air-to-air missile
An air-to-air missile is a missile fired from an aircraft for the purpose of destroying another aircraft. AAMs are typically powered by one or more rocket motors, usually solid fuelled but sometimes liquid fuelled...

 operated by the United States Air Force
United States Air Force
The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...

, United States Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...

 and United States Marine Corps
United States Marine Corps
The United States Marine Corps is a branch of the United States Armed Forces responsible for providing power projection from the sea, using the mobility of the United States Navy to deliver combined-arms task forces rapidly. It is one of seven uniformed services of the United States...

, as well as various allied air forces and navies. Sparrow and its derivatives were the West's principal beyond visual range (BVR) air-to-air missile from the late 1950s until the 1990s. It remains in service, although it is being phased out in aviation applications in favor of the more advanced AIM-120 AMRAAM
AIM-120 AMRAAM
The AIM-120 Advanced Medium-Range Air-to-Air Missile, or AMRAAM , is a modern beyond-visual-range air-to-air missile capable of all-weather day-and-night operations. Designed with the same form-factor as the previous generation of semi-active guided Sparrow missiles, it is a fire-and-forget...

. The Self-Defence Forces of Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

 also employ the Sparrow missile, though it is being phased out and replaced by the Mitsubishi AAM-4
Mitsubishi AAM-4
The Mitsubishi AAM-4 is a medium-range active radar-guided air-to-air missile developed in Japan and intended to replace the semi-active radar homing AIM-7 Sparrow missile in service...

. NATO pilots use the brevity code
Brevity code
Multiservice tactical brevity codes are codes used by various military forces. The codes procedure words, a type of voice procedure, are designed to convey complex information with a few words.-American/NATO codes:...

 Fox One
Fox (code word)
Fox is a brevity code used by NATO pilots to signal the simulated or actual release of an air-to-air munition or other combat function. Army aviation elements may use a different nomenclature, as the nature of helicopter fired weapons is almost always air-to-surface. 'Fox' is short for 'foxtrot',...

 in radio communication to signal launch of a Semi-Active Radar Homing Missile such as the Sparrow.

The Sparrow was used as the basis for a surface-to-air missile
Surface-to-air missile
A surface-to-air missile or ground-to-air missile is a missile designed to be launched from the ground to destroy aircraft or other missiles...

, the RIM-7 Sea Sparrow
RIM-7 Sea Sparrow
RIM-7 Sea Sparrow is a US ship-borne short-range anti-aircraft and anti-missile weapon system, primarily intended for defense against anti-ship missiles...

, which is used by the United States Navy for air defense of its ships.

Sparrow I

from a late-1940s United States Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...

 program to develop a guided rocket weapon for air-to-air use. In 1947
1947 in aviation
This is a list of aviation-related events from 1947:-January:* January 11 – The BOAC Douglas C-47A G-AGJX crashes into a hill at Stowting in southeast England, killing eight of the 16 people on board and injuring all eight survivors...

 the Navy contracted Sperry
Sperry Corporation
Sperry Corporation was a major American equipment and electronics company whose existence spanned more than seven decades of the twentieth century...

 to build a beam riding
Beam riding
Beam-riding, also known as beam guidance, is a technique of directing a missile to its target by means of radar or a laser beam. The name refers to the way the missile flies down the guidance beam, which is aimed at the target...

 version of a standard 5 inches (127 mm) HVAR
Hvar
- Climate :The climate of Hvar is characterized by mild winters and warm summers. The yearly average air temperature is , 686 mm of precipitation fall on the town of Hvar on average every year and the town has a total of 2800 sunshine hours per year. For comparison Hvar has an average of 7.7...

, the standard unguided aerial rocket, under Project Hotshot. The weapon was initially dubbed KAS-1, then AAM-2, and, from 1948
1948 in aviation
This is a list of aviation-related events from 1948:- Events :* Publication of Nevil Shute's novel No Highway set in the world of research into air safety.-January:...

 on, AAM-N-2. The airframe was developed by Douglas Aircraft Company
Douglas Aircraft Company
The Douglas Aircraft Company was an American aerospace manufacturer, based in Long Beach, California. It was founded in 1921 by Donald Wills Douglas, Sr. and later merged with McDonnell Aircraft in 1967 to form McDonnell Douglas...

. The diameter of the HVAR proved to be inadequate for the electronics, leading Douglas to expand the missile's airframe to 8 inches (203.2 mm) diameter. The prototype weapon began unpowered flight-tests in 1947, and made its first aerial interception in 1952
1952 in aviation
This is a list of aviation-related events from 1952:- Events :* The Royal Navy conducts the worlds first trials of an angled flight deck, aboard the aircraft carrier HMS Triumph. It had been invented by Royal Navy Captain Dennis R. F. Campbell,* The Royal Navy conducts the worlds first trials of a...

.

After a protracted development cycle the initial AAM-N-2 Sparrow entered service in 1956
1956 in aviation
This is a list of aviation-related events from 1956:-February:* February 18 – An engine fire breaks out on a Scottish Airlines Avro York just after takeoff from Malta International Airport, Luqa, Malta...

, carried by the F3H-2M Demon
F3H Demon
The McDonnell F3H Demon was a subsonic swept-wing United States Navy carrier-based jet fighter aircraft. After severe problems with Westinghouse J40 engine that was ultimately abandoned, the successor to the McDonnell F2H Banshee served starting in 1956 redesigned with the J71 engine...

 and F7U Cutlass
F7U Cutlass
The Vought F7U Cutlass was a United States Navy carrier-based jet fighter and fighter-bomber of the early Cold War era. It was a highly unusual, semi-tailless design, allegedly based on aerodynamic data and plans captured from the German Arado company at the end of World War II, though Vought...

 fighter aircraft
Fighter aircraft
A fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets...

. Compared to the modern versions, the Sparrow I was more streamlined
Streamliner
A streamliner is a vehicle incorporating streamlining in a shape providing reduced air resistance. The term is applied to high-speed railway trainsets of the 1930s to 1950s, and to their successor "bullet trains". Less commonly, the term is applied to fully faired recumbent bicycles...

 and featured a bullet-shaped airframe with a long pointed nose.

Sparrow I was a limited and rather primitive weapon. The limitations of beam-riding guidance (which was slaved to an optical sight, requiring visual identification of the target) restricted the missile to visual-range attacks and made it essentially useless against a maneuvering target. Only about 2,000 rounds were produced to this standard.

Sparrow II

As early as 1950 Douglas examined equipping the Sparrow with an active radar seeker, initially known as XAAM-N-2a Sparrow II, the original retroactively becoming Sparrow I. In 1952 it was given the new code AAM-N-3. The active radar made the Sparrow II a "fire and forget" weapon, allowing several to be fired at separate targets at the same time.

By 1955
1955 in aviation
This is a list of aviation-related events from 1955:- Events :* The United Kingdoms first atomic bomber unit, the Royal Air Forces No. 138 Squadron, becomes operational, flying Vickers Valiants.-January:...

 Douglas proposed going ahead with development, intending it to be the primary weapon for the F5D Skylancer
F5D Skylancer
|-See also:-References:NotesBibliography* Angelucci, Enzo. The American Fighter. Sparkford, Somerset, UK: Haynes Publishing Group, 1987. ISBN 0-85429-635-2....

 interceptor
Interceptor aircraft
An interceptor aircraft is a type of fighter aircraft designed specifically to prevent missions of enemy aircraft, particularly bombers and reconnaissance aircraft. Interceptors generally rely on high speed and powerful armament in order to complete their mission as quickly as possible and set up...

. It was later selected, with some controversy, to be the primary weapon for the Canadian Avro Arrow supersonic interceptor, along with the new Astra fire-control system. For Canadian use and as a second source for US missiles, Canadair
Canadair
Canadair Ltd. was a civil and military aircraft manufacturer in Canada. It was a subsidiary of other aircraft manufacturers, then a nationalized corporation until privatized in 1986, and became the core of Bombardier Aerospace....

 was selected to build the missiles in Quebec
Quebec
Quebec or is a province in east-central Canada. It is the only Canadian province with a predominantly French-speaking population and the only one whose sole official language is French at the provincial level....

.

However, the small size of the missile forebody and the K-band AN/APQ-64-radar limited performance, and it was never able to work in testing. After considerable development and test firings in the U.S. and Canada, Douglas abandoned development in 1956. Canadair continued development until the Arrow was cancelled in 1958
1958 in aviation
This is a list of aviation-related events from 1958:- Events :* Gulfstream Aerospace is founded in Savannah, Georgia, in the United States.* The Argentine Navy acquires its first aircraft carrier by purchasing HMS Warrior from the United Kingdom....

.

Sparrow X

A subvariant of the Sparrow I armed with the same nuclear warhead as the MB-1 Genie
AIR-2 Genie
The Douglas AIR-2 Genie was an unguided air-to-air rocket with a 1.5kt W25 nuclear warhead. It was deployed by the United States Air Force and Canada during the Cold War...

 was proposed in 1958, but was cancelled shortly thereafter.

Sparrow III

Concurrently with the development of the Sparrow I, in 1951
1951 in aviation
This is a list of aviation-related events from 1951:-Events:* Three aerial refueling points are installed on a modified United States Air Force B-29 Superfortress, making it the worlds first triple-point aerial tanker...

, Raytheon
Raytheon
Raytheon Company is a major American defense contractor and industrial corporation with core manufacturing concentrations in weapons and military and commercial electronics. It was previously involved in corporate and special-mission aircraft until early 2007...

 began work on the semi-active radar homing
Semi-active radar homing
Semi-active radar homing, or SARH, is a common type of missile guidance system, perhaps the most common type for longer-range air-to-air and surface-to-air missile systems. The name refers to the fact that the missile itself is only a passive detector of a radar signal – provided by an external ...

 version of Sparrow family of missiles, the AAM-N-6 Sparrow III. The first of these weapons entered United States Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...

 service in 1958
1958 in aviation
This is a list of aviation-related events from 1958:- Events :* Gulfstream Aerospace is founded in Savannah, Georgia, in the United States.* The Argentine Navy acquires its first aircraft carrier by purchasing HMS Warrior from the United Kingdom....

.

The AAM-N-6a was similar to the -6, but used a new Thiokol
Thiokol
Thiokol is a U.S. corporation concerned initially with rubber and related chemicals, and later with rocket and missile propulsion systems...

 liquid-fuel rocket engine for improved performance. It also included changes to the guidance electronics to make it effective at higher closing speeds. The -6a was also selected to arm the Air Force's F-110A Spectre(F-4 Phantom) fighters in 1962
1962 in aviation
This is a list of aviation-related events from 1962:- Events :* Early 1962 – In Operation High Jump, the United States Navy McDonnell F4H-1 Phantom II fighter sets a number of world climb-to altitude records: 34.523 seconds to 3,000 meters , 48.787 seconds to 6,000 meters , 61.629 seconds to...

, known to them as the AIM-101. It entered production in 1959, with 7500 being built.

Another upgrade reverted to a Rocketdyne solid-fuel motor for the AAM-N-6b, which started production in 1963
1963 in aviation
This is a list of aviation-related events from 1963:- Events :* Violating a 1959 requirement that all aircraft operating from the aircraft carrier Minas Gerais - which never has operated aircraft - belong to the Brazilian Air Force, the Brazilian Navy establishes an air group of its own for the...

. The new motor significantly increased maximum range to 35 kilometres (21.7 mi) for head-on attacks.

During this year the Navy and Air Force agreed on standardized naming conventions for their missiles. The Sparrows became the AIM-7 series. The original Sparrow I and aborted Sparrow II became the AIM-7A and AIM-7B, despite both being out of service. The -6, -6a and -6B became the AIM-7C, AIM-7D and AIM-7E respectively.

25,000 AIM-7Es were produced, and saw extensive use during the Vietnam War
Vietnam War
The Vietnam War was a Cold War-era military conflict that occurred in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. This war followed the First Indochina War and was fought between North Vietnam, supported by its communist allies, and the government of...

, where its performance was generally considered disappointing. The mixed results were a combination of reliability problems (exacerbated by the tropical climate), limited pilot training in fighter-to-fighter combat, and restrictive rules of engagement that generally prohibited BVR (beyond visual range) engagements. The Pk (kill probability) of the AIM-7E was less than 10%; US fighter pilots shot down 55 aircraft using the Sparrow.

In 1969
1969 in aviation
This is a list of aviation-related events from 1969:- Events :* The Canadian Snowbirds aerobatic team is formed.* A fifth annual Harmon Trophy is created to honor the worlds outstanding astronaut of the year and is awarded for the first time, honoring the outstanding astronauts of 1968.-January:*...

 an improved version, the E-2, was introduced with clipped wings and various changes to the fuzing. Considered a "dogfight Sparrow", the AIM-7E-2 was intended to be used at shorter ranges where the missile was still travelling at high speeds, and in the head-on aspect, making it much more useful in the visual limitations imposed on the engagements. Even so, its kill rate was only 13% in actual combat in 1972, leading to a practice of ripple-firing all four at once in hopes of increasing kill probability. Its worst tendency was that of detonating prematurely, approximately a thousand feet in front of the launching aircraft, but it also had many motor failures, erratic flights, and fuzing problems. An E-3 version included additional changes to the fuzing, and an E-4 featured a modified seeker for use with the F-14 Tomcat
F-14 Tomcat
The Grumman F-14 Tomcat is a supersonic, twin-engine, two-seat, variable-sweep wing fighter aircraft. The Tomcat was developed for the United States Navy's Naval Fighter Experimental program following the collapse of the F-111B project...

.

Improved versions of the AIM-7 were developed in the 1970s in an attempt to address the weapon's limitations. The AIM-7F, which entered service in 1976
1976 in aviation
This is a list of aviation-related events from 1976:-January:*January 1 - Middle East Airlines Flight 438, a Boeing 720, aircraft over Saudi Arabia when bomb exploded in the forward baggage compartment, aircraft destroyed killing 81.-March:...

, had a dual-stage rocket motor for longer range, solid-state electronics for greatly improved reliability, and a larger warhead. Even this version had room for improvement, leading British Aerospace
British Aerospace
British Aerospace plc was a UK aircraft, munitions and defence-systems manufacturer. Its head office was in the Warwick House in the Farnborough Aerospace Centre in Farnborough, Hampshire...

 and the Italian firm Selenia to develop advanced versions of Sparrow with better performance and improved electronics as the Skyflash
Skyflash
The British Aerospace Skyflash was a medium-range semi-active radar homing air-to-air missile derived from the US AIM-7 Sparrow missile and carried by Royal Air Force F-4 Phantoms and Tornado F3s, Italian Aeronautica Militare and Royal Saudi Air Force Tornados and Swedish Flygvapnet Viggens...

 and Selenia Aspide, respectively.

The most common version of the Sparrow today, the AIM-7M, entered service in 1982
1982 in aviation
This is a list of aviation-related events from 1982:-January:* January 8 - The Airbus A300 is certified, becoming the first wide-body airliner with cockpit accommodations for only two to be certified....

 and featured a new inverse monopulse seeker (matching the capabilities of Skyflash), active radar fuse, digital controls, improved ECM
Electronic countermeasures
An electronic countermeasure is an electrical or electronic device designed to trick or deceive radar, sonar or other detection systems, like infrared or lasers. It may be used both offensively and defensively to deny targeting information to an enemy...

 resistance, and better low-altitude performance. It was used to good advantage in the 1991 Gulf War
Gulf War
The Persian Gulf War , commonly referred to as simply the Gulf War, was a war waged by a U.N.-authorized coalition force from 34 nations led by the United States, against Iraq in response to Iraq's invasion and annexation of Kuwait.The war is also known under other names, such as the First Gulf...

, where it scored many USAF air-to-air kills; however its kill probability, overall, is still less than 40%.

The AIM-7P is similar in most ways to the M versions, and was primarily an upgrade program for existing M-series missiles. The main changes were to the software, improving low-level performance. A follow-on Block II upgrade added a new rear receiver allowing the missile to receive mid-course correction from the launching aircraft. Plans initially called for all M versions to be upgraded, but currently P's are being issued as required to replace M's lost or removed from the inventory.

The final version of the missile was to have been the AIM-7R, which added an infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...

 seeker to an otherwise unchanged AIM-7P Block II. A general wind-down of the budget led to it being cancelled in 1997.

Sparrow is now being phased out with the availability of the active-radar AIM-120 AMRAAM
AIM-120 AMRAAM
The AIM-120 Advanced Medium-Range Air-to-Air Missile, or AMRAAM , is a modern beyond-visual-range air-to-air missile capable of all-weather day-and-night operations. Designed with the same form-factor as the previous generation of semi-active guided Sparrow missiles, it is a fire-and-forget...

, but is likely to remain in service for a number of years.

Canada

As part of the Avro Arrow program, Canadair partnered with Douglas in the development of the Sparrow II (AIM-7B). After Douglas dropped out of this program, Canadair
Canadair
Canadair Ltd. was a civil and military aircraft manufacturer in Canada. It was a subsidiary of other aircraft manufacturers, then a nationalized corporation until privatized in 1986, and became the core of Bombardier Aerospace....

 continued on with it until the termination of the Arrow.

Italy

The Italian company Finmeccanica, Alenia Difesa licensed the AIM-7E Sparrow technology from US, and produced its own improved version called Aspide.

UK

British Aerospace
British Aerospace
British Aerospace plc was a UK aircraft, munitions and defence-systems manufacturer. Its head office was in the Warwick House in the Farnborough Aerospace Centre in Farnborough, Hampshire...

 (BAe) licensed the AIM-7E2 technology in the 1970s, producing the Skyflash missile. Skyflash used a Marconi XJ521 monopulse Semi-Active seeker together with improvements to the electronics. It was powered by the Aerojet Mk52 mod 2 rocket engine (later by the Rocketdyne Mk38 mod 4). Skyflash entered service with the Royal Air Force
Royal Air Force
The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...

 (RAF) on their Phantom FG.1/FGR.2
F-4 Phantom II
The McDonnell Douglas F-4 Phantom II is a tandem two-seat, twin-engined, all-weather, long-range supersonic jet interceptor fighter/fighter-bomber originally developed for the United States Navy by McDonnell Aircraft. It first entered service in 1960 with the U.S. Navy. Proving highly adaptable,...

 in 1976, and later on the Tornado F3
Panavia Tornado ADV
The Panavia Tornado Air Defence Variant is a long-range, twin-engine interceptor version of the swing-wing Panavia Tornado. The aircraft's first flight was on 27 October 1979, and it entered service in 1986. It was retired on 22 March 2011 by the Royal Air Forceand is now only in service with the...

. The Skyflash was also exported to Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....

 for use on their Viggen
Viggen
Viggen can refer to three distinct vehicles:*Saab 37 Viggen, the original Swedish name for the Saab 37 fighter aircraft*The name of a special version of a Saab 9-3 automobile*The Rutan VariViggen, a homebuilt aircraft kit designed by Burt Rutan...

 fighters.

An upgraded version with active radar seeker, called Active Sky Flash was proposed by BAe and Thomson-CSF
Thomson-CSF
Thomson-CSF was a major electronics and defence contractor. In December 2000 it was renamed Thales Group.-History:In 1879 Elihu Thomson and Edwin Houston formed the Thomson-Houston Electric Company in the United States....

, but did not receive funding because the RAF opted for other missiles.

People's Republic of China

The LY-60/FD-60/PL-10 is a family of PRC missiles developed by the Shanghai Academy of Science and Technology, largely based on the Italian Aspide missile - itself a version of the Sparrow. There are four versions of the basic design, three of which are surface-to-air and one air-to-air.

Design

The Sparrow has four major sections: guidance section, warhead
Warhead
The term warhead refers to the explosive material and detonator that is delivered by a missile, rocket, or torpedo.- Etymology :During the early development of naval torpedoes, they could be equipped with an inert payload that was intended for use during training, test firing and exercises. This...

, control, and rocket motor (currently the Hercules MK-58 solid-propellant rocket motor). It has a cylindrical body with four wings at mid-body and four tail fins. Although the external dimensions of the Sparrow remained relatively unchanged from model to model, the internal components of newer missiles represent major improvements, with vastly increased capabilities. The warhead is of the continuous-rod
Continuous-rod warhead
A continuous-rod warhead is a specialized munition that exhibits an annular blast fragmentation pattern. It is used in anti-aircraft and anti-missile missiles.-Early anti-aircraft munitions:...

 type.

As with other semi-active radar guided missiles, the missile does not generate radar signals, but instead homes in on reflected continuous-wave signals from the launch platform's radar. The receiver also senses the guidance radar to enable comparisons that enhance the missile's resistance to passive jamming.

Principle of guidance (semi-active version)

The launching aircraft will illuminate the target with its radar. In radars of the 1950s these were single target tracking devices using a nutating
Nutation
Nutation is a rocking, swaying, or nodding motion in the axis of rotation of a largely axially symmetric object, such as a gyroscope, planet, or bullet in flight, or as an intended behavior of a mechanism...

 horn as part of its antenna. This caused the beam to be swept in a small cone. Signal processing would be applied to determine the direction of maximum illumination and so develop a signal to steer the antenna toward the target. The missile detects the reflected signal from the target with a high gain antenna in a similar fashion and steers the entire missile toward closure with the target. The missile guidance also samples a portion of the illuminating signal via rearward pointing waveguide
Waveguide
A waveguide is a structure which guides waves, such as electromagnetic waves or sound waves. There are different types of waveguides for each type of wave...

s. The comparison of these two signals enabled logic circuits to determine the true target reflection signal, even if the target were to eject radar-reflecting chaff
Chaff (radar countermeasure)
Chaff, originally called Window by the British, and Düppel by the Second World War era German Luftwaffe , is a radar countermeasure in which aircraft or other targets spread a cloud of small, thin pieces of aluminium, metallized glass fibre or plastic, which either appears as a cluster of secondary...

.

See also

  • AIM-9 Sidewinder
    AIM-9 Sidewinder
    The AIM-9 Sidewinder is a heat-seeking, short-range, air-to-air missile carried mostly by fighter aircraft and recently, certain gunship helicopters. The missile entered service with United States Air Force in the early 1950s, and variants and upgrades remain in active service with many air forces...

  • AIM-54 Phoenix
    AIM-54 Phoenix
    The AIM-54 Phoenix is a radar-guided, long-range air-to-air missile , carried in clusters of up to six missiles on F-14 Tomcats, its only launch platform. The Phoenix was the United States' only long-range air-to-air missile. The weapons system based on Phoenix was the world's first to allow...

  • Brazo (missile)
  • Vympel R-27
  • List of missiles
  • Missile designation
    Missile designation
    The U.S. Department of Defense established a missile and rocket designation sequence, which is used in all weapons of the kind produced in the USA.-Explanation:The basic designation of every guided missile is based in a set of letters, which are in sequence...


External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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