View source for Active protection system

{{Short description|Type of military anti-projectile defense system}}
[[File: Arena system.svg|thumb|[[Arena (countermeasure)|Arena Active Protection System]]: <br/>
1. Protective siloes <br/>
2. Radar <br/>
3. Protective ammo <br/>
4. Incoming anti-tank guided missile <br/>
5. Tracking phase|550x550px]]
An '''active protection system''' ('''APS''') is a system designed to actively prevent certain anti-tank weapons from destroying a vehicle.

Countermeasures that either conceal the vehicle from or disrupt the guidance of an incoming [[guided missile]] threat are designated '''soft-kill''' active protection measures. Countermeasures that physically strike an incoming threat to damage or destroy it and thereby limit its ability to penetrate armor are designated '''hard-kill''' active protection measures.

==Soft-kill measures==
Soft-kill measures are designed to defeat guided weapons either by concealing the protected vehicle from them (for example, with a [[smoke screen]]) or by disrupting their guidance with radiation (for example, with a [[Dazzler (weapon)|dazzler]]). Some systems use laser dazzlers to blind the operator or sensors of [[semi-automatic command to line of sight]] (SACLOS) [[anti-tank guided missiles]] (ATGMs), such as the JD-3 of the [[Type 99 tank]]. Others use powerful infrared emitters to mask the IR tracking flare present on many SACLOS ATGMs, such as the [[Shtora-1]].

Soft-kill measures can be divided into '''on-board''' countermeasures, such as dazzlers, which are fixed to the platform and '''expendable''' countermeasures, such as smoke grenades, which are ejected upon use.

Soft-kill measures may be used preemptively, but are more commonly employed in reaction to detected threats.

==Hard-kill measures==
Hard-kill measures kinetically attack threatening missiles or other munitions, usually at very close range to the protected vehicle.
[[Explosively formed penetrators]] (EFPs) or high explosive fragmentation countermeasures are typically used. The exact mechanism of many APSs has not been published.
The action of these countermeasures may lead to:
*disturbance of the stability of a [[kinetic energy penetrator]] which will decrease its penetration ability as the deflection angle increases.
*premature initiation of a [[shaped charge]] (e.g., too great stand-off), but most likely improper initiation, thereby impeding optimum jet development of the metallic lining, usually copper, in the shaped charge.  The copper jet provides most of the anti armor capabilities of shaped charge weapons.
*destruction of the [[airframe]] of an inbound [[missile]] or [[Shell (projectile)|shell]].

[[File:Merkava4m-Windbreaker-0036a.jpg|thumb|[[Merkava]] Mk IVm Windbreaker, fitted with [[Trophy (countermeasure)|Trophy]] APS]]
There are many examples of hard kill countermeasures.  The Russian [[Arena (countermeasure)|Arena]] system utilizes a [[Doppler radar]] to detect incoming threats and fires munition to eliminate the threat.  The Israeli [[Trophy (countermeasure)|Trophy]] system fires a multiple explosively formed penetrator (MEFP) to destroy the threat. An American system known as [[Quick Kill]] detects incoming threats using an [[Active Electronically Scanned Array]], which assesses the threat, and deploys a smaller rocket countermeasure.  Another American system, known as [[Iron Curtain (countermeasure)|Iron Curtain]], utilizes two sensors to reduce false alarms and defeat threats inches from their target by firing a kinetic countermeasure designed to minimize collateral damage. The Russian [[Afganit]] active protection system of the [[Armata Universal Combat Platform|Armata]] AFVs features a millimeter-wavelength radar to detect and track incoming [[anti-tank warfare|anti-tank]] munitions. It can reportedly intercept [[armour-piercing fin-stabilized discarding sabot]] [[kinetic energy penetrator]]s in addition to [[high-explosive anti-tank]] (HEAT) munitions.<ref name=vpk>{{cite news|url=http://vpk.name/library/f/armata.html |title=Танк Т-14 "Армата" или Т-99 "Приоритет" |publisher=vpk.name |access-date=6 May 2015 |trans-title=Tank T-14 "Armata" or T-99 "priority" |language=ru}}</ref><ref name="fmso.leavenworth.army.mil">{{Cite web |url=http://fmso.leavenworth.army.mil/OEWatch/201503/201503.pdf |title=Archived copy |access-date=2017-03-26 |archive-url=https://web.archive.org/web/20150518093100/http://fmso.leavenworth.army.mil/OEWatch/201503/201503.pdf |archive-date=2015-05-18 |url-status=dead }}</ref>

==Potential performance problems==

===Clutter===
Mountains and neighboring vehicles reflect [[radio wave]]s, thus creating [[Clutter (radar)|radar clutter]], which adversely affects radar-detection and radar-lock performance.{{citation needed|date=February 2013}}

===Top attack munitions===
The trajectories of [[top attack]] ATGMs like the [[FGM-148 Javelin]] (US) and [[Trigat]] (Germany) plunge down onto their targets. Not all active protection systems are designed to fire at the extreme elevations necessary to protect against such munitions. RPGs fired at a steep downward angle from elevated positions can pose a similar threat.

==Examples by country of origin==
<!-- New links in alphabetical order please -->

===Hard-kill measures===
[[File:FCS Quick Kill.webm|thumb|right|American [[Quick Kill]] system takes out an RPG in a test October 2007]]
; {{flag|China}}
:* [[GL5 Active Protection System|GL5]]
; {{flag|France}}
:* [[Thales DIAMANT|DIAMANT]]
; {{flag|Germany}}
:* [[AMAP-ADS]]
; {{flag|Israel}}
:* [[Iron Fist (countermeasure)|Iron Fist]]
:* [[Trophy (countermeasure)|Trophy]]
; {{flag|Russia}}
:* [[Afganit]]
:* [[Arena (countermeasure)|Arena]]
:* [[Drozd]]
; {{flag|South Africa}} / {{flag|Sweden}}
:* [[LEDS-150]]
; {{flag|South Korea}}
:* [[KAPS (countermeasure)|KAPS]]
; {{flag|United States}}
:* [[Iron Curtain (countermeasure)|Iron Curtain]]
:* [[Quick Kill]]
; {{flag|Ukraine}}
:* [[Zaslin Active Protection System|Zaslin]]

===Soft-kill measures===
; {{flag|Germany}}
:* [[MUSS (countermeasure)|MUSS]]
; {{flag|Poland}}
:* [[Obra-3]]
; {{flag|Russia}}
:* [[Shtora-1]]
; {{flag|Ukraine}}
:* [[Guard (countermeasure)|Guard]]
; {{flag|South Korea}}
:* [[K2_Black_Panther#Active_protection_systems|MSSG]]
; {{flag|Syria}}
:* [[Sarab Active Protection System|Sarab]]
; {{flag|United States}}
:* [[AN/VLQ-6 MCD]]

==See also==
<!-- New links in alphabetical order please -->
*[[Anti-aircraft]]
*[[Anti-ballistic missile]]
*[[B-52_Stratofortress#Overview|B-52]]/[[Convair_B-58_Hustler#Weapons_systems|B-58]] Turret
*[[Close-in weapon system]]
*[[Digital Radio Frequency Memory]]
*[[Electronic countermeasures]]
*[[Flare (countermeasure)]]
*[[Infrared countermeasures]]
*[[National Missile Defense]]
*[[Reactive armor]]
*[[Strategic Defense Initiative]]
*[[Sentry gun]]

==References==
{{Reflist}}
*[https://web.archive.org/web/20100829044326/http://www.diehl-bgt-defence.de/index.php?id=547&L=1 DIRCM and AVePS ]

== External links ==
*[http://www.fas.org/man/dod-101/sys/land/docs/3aps98.pdf. Access on Jan 11, 2011. Active Protective Systems: Impregnable Armor or Simply Enhanced Survivability?] &mdash; An overview of modern tank active protection systems (PDF)
*[https://web.archive.org/web/20060426013156/http://www.defense-update.com/features/du-1-04/Hard-kill.htm Active Protective Systems overview - Defense Update]
*[https://web.archive.org/web/20090310041758/http://www.defense-update.com/features/du-1-04/soft-kill-west.htm Soft Kill Active Protective Systems overview - Defense Update]

== Further reading ==
	
*{{cite report |last1= Feickert |first1=Andrew |date=30 August 2016 |title=Army and Marine Corps Active Protection System (APS) Efforts |url=https://apps.dtic.mil/sti/pdfs/AD1015880.pdf |publisher=Congressional Budget Office |access-date= 20 September 2023}}
{{APS}}

{{DEFAULTSORT:Active Protection System}}
[[Category:Armoured fighting vehicle equipment]]
[[Category:Weapons countermeasures]]
[[Category:Soviet inventions]]