Air Defense Systems

Man-portable air-defense systems

Man-portable air-defense systems (MANPADS) are shoulder-launched surface-to-air missiles (SAMs). They typically use infra-red guidance and are a threat to low-flying aircraft, especially helicopters.

Overview

MANPADS were originally developed in the late 1950s to provide military ground forces protection from enemy aircraft. They are receiving a great deal of attention as potential terrorist weapons that might be used against commercial airliners. These missiles, affordable and widely available through a variety of sources, have been used successfully over the past three decades both in military conflicts, as well as by terrorist organizations. They can be purchased on the black market anywhere from a few hundred dollars (USD) for older models to upwards of almost a quarter million dollars for newer, more capable models. Twenty-five countries, including the United States, produce man-portable air defense systems. Possession, export, and trafficking in such weapons is officially tightly controlled, due to the threat they pose to civil aviation, although such efforts have not always been successful.

The missiles are about 5 to in length and weigh about 35 to , depending on the model. Shoulder-fired SAMs generally have a target detection range of about and an engagement range of about , so aircraft flying at (3.8 miles) or higher are relatively safe.

Missile types

Unguided

In 1944, Nazi Germany was desperately short of mobile air-defense weapons. Borrowing from the concept of the simple and effective anti-tank Panzerfaust, an unguided multibarreled 20mm rocket launcher, the Fliegerfaust, was developed. The weapon never reached mass production due to the end of World War II.

Following the end of World War II, Soviet designers also experimented with unguided multibarreled rocket launchers but this design concept was abandoned in favor of guided missiles equipped with an infrared sensor.

Infrared

Infrared shoulder-fired missiles are designed to home in on a heat source on an aircraft, typically the engine exhaust plume, and detonate a warhead in or near the heat source to disable the aircraft. These missiles use passive guidance, meaning that they do not emit signals to detect a heat source, which makes them difficult to detect by targeted aircraft employing countermeasure systems.

First generation

The first missiles deployed in the 1960s were IR missiles. First generation shoulder-fired SAMs such as the U.S. Redeye, early versions of the Soviet SA-7, and the Chinese HN-5 are considered "tail chase weapons" as their seekers can only acquire and engage a high performance aircraft after it has passed the missile’s firing position. In this flight profile, the aircraft’s engines are fully exposed to the missile’s seeker and provide a sufficient thermal signature for engagement. First generation IR missiles are also highly susceptible to interfering thermal signatures from background sources, including the sun, which many experts feel makes them somewhat unreliable.

Second generation

Second generation IR missiles such as early versions of the U.S. Stinger, the Soviet SA-14, and the Chinese FN-6 use improved coolants to cool the seeker head which enables the seeker to filter out most interfering background IR sources as well as permitting head-on and side engagement profiles. These missiles also employ technologies to counter decoy flares that might be deployed by targeted aircraft and also have backup target detection modes such as the ultraviolet (UV) mode found on the Stinger missile.

Third generation

Third generation IR shoulder-fired SAMs such as the French Mistral, the Russian SA-18, and the U.S. Stinger B use single or multiple detectors to produce a quasi-image of the target and also have the ability to recognize and reject flares dispensed from aircraft.

Fourth generation

Fourth generation missiles such as the U.S. Stinger Block 2, and missiles believed to be under development in Russia, Japan, France, and Israel could incorporate focal plane array guidance systems and other advanced sensor systems which will permit engagement at greater ranges.

Command line-of-sight

Command line-of-sight (CLOS) missiles do not home in on a particular aspect (heat source or radio or radar transmissions) of the targeted aircraft. Instead, the missile operator or gunner visually acquires the target using a magnified optical sight and then uses radio controls to "fly" the missile into the aircraft. One of the benefits of such a missile is that it is virtually immune to flares and other basic countermeasure systems which are designed primarily to defeat IR missiles. The major drawback of CLOS missiles is that they require highly trained and skilled operators. Numerous reports from the Soviet-Afghan War in the 1980s cite Afghan mujahedin as being disappointed with the British-supplied Blowpipe CLOS missile because it was too difficult to learn to use and highly inaccurate, particularly when employed against fast moving jet aircraft. Given these considerations, many experts believe that CLOS missiles are not as ideally suited for terrorist use as are IR missiles, which sometimes are referred to as "fire and forget" missiles.

Later versions of CLOS missiles, such as the British Javelin, use a solid state television camera in lieu of the optical tracker to make the gunner's task easier. The Javelin’s manufacturer, Thales Air Defence claims that their missile is virtually impervious to countermeasures. Even more advanced CLOS versions, such as the British Starburst, use a laser data link in lieu of earlier radio guidance links to fly the missile to the target.

Laser guided

Laser guided shoulder-fired SAMs use lasers to guide the missiles to the target. The missile flies along the laser beam and strikes the aircraft where the missile operator or gunner aims the laser. Missiles such as Sweden’s RBS-70 and Britain’s Starstreak can engage aircraft from all angles and only require the operator to continuously track the target using a joystick to keep the laser aim point on the target. Because there are no data links from the ground to the missile, the missile cannot be effectively jammed after it is launched. Future laser guided SAMs may require the operator to designate the target only once and not manually keep a continuous laser aimpoint on the aircraft. Even though laser guided missiles require relatively extensive training and skill to operate, many experts consider these missiles particularly menacing in the hands of terrorists due to the missiles’ resistance to most conventional countermeasures in use today.

Notable uses against military aircraft

Notable uses against civilian aircraft

Countermeasures

Military countermeasures

  • AN/ALQ-144, AN/ALQ-147 and AN/ALQ-157 are U.S.-produced systems, developed by Sanders Associates in the 1970s.

With the growing number of MANPADS attacks on civilian airliners, number of different countermeasure systems have been developed specifically to protect aircraft against the missiles.

Civilian countermeasures

Missile models

See also

References

Portions of this article were taken from Homeland Security: Protecting Airliners from Terrorist Missiles, CRS Report for Congress RL31741, February 16, 2006 by the Congressional Research Service, division of The Library of Congress which as a work of the Federal Government exists in the public domain.

External links

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