Active protection system

An active protection system, or APS, protects a tank or other armoured fighting vehicle from incoming fire "before" it hits the vehicle's armour. There are two general categories: "soft kill" systems, which use jamming or decoys to confuse a missile's guidance system, and "hard kill" systems, which attempt to detect and destroy incoming projectiles.

Land vehicle APS

Soft-kill systems were (unsuccessfully) deployed by Iraq in the Gulf War. Iraqi tanks were fitted with strobe lights that masqueraded as the guidance beacon on the back of a TOW missile. The multinational force was aware of their use and adjusted the frequency of their guidance systems so they would not be confused Fact|date=May 2008. A soft-kill system currently in service is the Russian Shtora, deployed on Russian and Ukrainian tanks.

Hard-kill systems are activated when a millimetre-wavelength radar or other sensor detects an incoming projectile. In considerably less than a second, they launch a counter-projectile in an attempt to physically damage or destroy the incoming round. Examples include the TROPHY and Iron Fist from Israel, the Quick Kill system from the United States, and the Russian Drozd and Arena.

Aircraft APS

Attempts to use aircraft-mounted flak cannon as such an APS against anti-aircraft missiles proved ineffectiveFact|date=February 2007. Anti-aircraft missiles are designed for effectiveness in a near-miss shot, making APS inefficient and unreliable. Among the effective countermeasures for aircraft are ECM, flares or anti-radar chaff.

DARPA is presently developing the High Energy Liquid Laser Area Defense System, which is planned to be capable of knocking out missiles, and may be used to actively defend future combat aircraft.

Naval APS

Warships have been equipped with similar systems (more frequently known as Close-In Weapon Systems, CIWS), which use small- to medium-caliber (12.7-76mm) guns and guided missiles to destroy inbound missiles and cannon shells. Examples include the US Phalanx CIWS, Dutch Goalkeeper, Russian Kashtan, joint USA/German Rolling Airframe Missile, British Sea Wolf, Chinese Type 730 and Turkish Sea Zenith.

In popular culture

*In the film "Die Another Day", James Bond's modified Aston Martin Vanquish was portrayed with twin bonnet-mounted automatic shotguns as a hard-kill system to destroy mortar rounds.
*The computer game features a Paladin tank (as opposed to the real M109 Paladin motorised artillery) which has a turret mounted laser active kill system, effective at destroying missile projectiles. In the expansion pack for it, (Zero Hour) the U.S Air Force General's aircraft are fitted with Laser Defenses to destroy incoming missiles.
*In Battlefield 2142 by DiCE and EA, the battlewalkers, aircraft, and other vehicles possess an active defense shield system that stops any incoming large fire before it impacts the vehicle during the limited time it is active.
*In the television sci-fi series Babylon 5, Earthforce ships and stations like Babylon 5 itself have "Interceptors" which are basically gun emplacements that target and destroy incoming enemy fire.
*The popular Macross series often depicts the Variable Fighters using their gunpods or, in the case of VF-1 (and possibly other models as well), specialized laser cannons to destroy missiles before they come into contact.
*Armored Core series games also utilize this effect, either as built-in systems, or as additional functions. Although so far, the system only works against missile weaponries.
*Supreme Commander strategic PC game has several anti-missile defence systems, including anti-missile missiles, flak guns and ray defence systems. There are also jamming based anti-missile defences and missile counter-counter-measures. While futuristic, they give good range of possible (and arguably feasible) defence systems technologies.
*The Hammer's Slammers books by David Drake feature armoured fighting vehicles armed with rapid-fire energy weapons that can bring down guided missiles and artillery shells. They also have a second line of defense in the form of explosive strips bordering their hulls. These function as directional mines, capable of knocking out incoming RPGs ("buzzbombs") launched too closely for the energy weapons to deal with.

External links

* [http://www.knox.army.mil/center/ocoa/ArmorMag/mj98/3aps98.pdf Active Protective Systems: Impregnable Armor or Simply Enhanced Survivability?] — An overview of modern tank active protection systems (PDF)
* [http://www.defense-update.com/features/du-1-04/Hard-kill.htm Active Protective Systems overview - Defense Update]
* [http://www.defense-update.com/features/du-1-04/soft-kill-west.htm Soft Kill Active Protective Systems overview - Defense Update]