Editing Surface-to-air missile (section)

==General information==
Surface-to-air missiles are classified by their [[Missile guidance|guidance]], mobility, [[altitude]] and [[Trajectory of a projectile|range]].

===Mobility, maneuverability and range===
[[File:Night launch of a RIM-161 Standard SM-3.jpg|thumb|left|upright|Long-range SAMs like the [[RIM-161]] are an important part of modern naval forces.]]
[[File:Granit 2023 - 102 - FK-3.jpg|thumb|[[HQ-22|FK-3]], the export version of the Chinese HQ-22 system of the [[Serbian Air Force and Air Defence]]]]

Missiles able to fly longer distances are generally heavier, and therefore less mobile. This leads to three "natural" classes of SAM systems; heavy long-range systems that are fixed or semi-mobile, medium-range vehicle-mounted systems that can fire on the move, and short-range [[man-portable air-defense system]]s (MANPADS).
[[File:Jan. 25, 2017 David’s Sling Test-5 test series (1).jpg|thumb|The [[David's Sling]] Stunner missile is designed for super-maneuverability. A three-pulse motor activates only during the kill-stage, providing additional acceleration and maneuverability.<ref name="ReferenceA">{{citation |title=Missile-Killing Interceptors Eyed By Israel, US |work=Aviation Week's DTI |first=David A. |last=Fulghum |date=23 September 2010}}</ref>]]

Modern long-range weapons include the [[MIM-104 Patriot]] and [[S-300 missile system|S-300]] systems, which have effective ranges on the order of {{cvt|150|km}} and offer relatively good mobility and short unlimbering times. These compare with older systems with similar or less range, like the [[MIM-14 Nike Hercules]] or [[S-75 Dvina]], which required fixed sites of considerable size. Much of this performance increase is due to improved rocket fuels and ever-smaller electronics in the guidance systems. Some very long-range systems remain, notably the Russian [[S-400]], which has a range of {{cvt|400|km}}.<ref>{{Cite web |title=S-400 Triumf |url=https://missilethreat.csis.org/defsys/s-400-triumf/ |access-date=2024-10-09 |website=Missile Threat |language=en-US}}</ref>

Medium-range designs, like the [[Rapier (missile)|Rapier]] and [[2K12 Kub]], are specifically designed to be highly mobile with very fast, or zero, setup times. Many of these designs were mounted on armoured vehicles, allowing them to keep pace with mobile operations in a conventional war. Once a major group unto itself, medium-range designs have seen less development since the 1990s, as the focus has changed to unconventional warfare.

Developments have also been made in onboard maneuverability. Israel's [[David's Sling]] Stunner missile is designed to intercept the newest generation of tactical ballistic missiles at low altitude. The multi-stage interceptor consists of a solid-fuel, rocket motor booster, followed by an asymmetrical [[Projectile|kill vehicle]] with advanced steering for super-maneuverability during the kill-stage. A three-pulse motor provides additional acceleration and maneuverability during the terminal phase.<ref name="ReferenceA"/>

MANPAD systems first developed in the 1960s and proved themselves in battle during the 1970s. MANPADS normally have ranges on the order of {{cvt|3|km}} and are effective against [[attack helicopter]]s and aircraft making ground attacks. Against fixed wing aircraft, they can be very effective, forcing them to fly outside the missile's envelope and thereby greatly reducing their effectiveness in ground-attack roles. MANPAD systems are sometimes used with vehicle mounts to improve maneuverability, like the [[AN/TWQ-1 Avenger|Avenger]] system. These systems have encroached on the performance niche formerly filled by dedicated mid-range systems.

'''Ship-based anti-aircraft missiles''' are also considered to be SAMs, although in practice it is expected that they would be more widely used against [[sea skimming]] missiles rather than aircraft{{citation needed|date=January 2021}}.  Virtually all surface [[warship]]s can be armed with SAMs, and naval SAMs are a necessity for all front-line surface warships. Some warship types specialize in anti-air warfare e.g. {{sclass|Ticonderoga|cruiser|0}} cruisers equipped with the [[Aegis combat system]] or {{sclass|Kirov|battlecruiser|0}} cruisers with the [[S-300 missile system#S-300F|S-300F]] ''Fort'' missile system. Modern Warships may carry all three types (from long-range to short-range) of SAMs as a part of their multi-layered air defence.

===Guidance systems===
{{main|Missile guidance}}
[[File:2019 Sacred Defence Week parade (310).jpg|thumb|Fire control radar of Iranian [[Bavar 373]] SAM system]]
[[File:Arrow-3 Jan-03-2013 (c).jpg|thumb|Israel's [[Arrow 3]] missiles use a [[gimbal]]ed seeker for [[Hemispherical|hemispheric]] coverage. By measuring the seeker's [[line-of-sight propagation]] relative to the vehicle's motion, they use [[proportional navigation]] to divert their course and line up exactly with the target's flight path.<ref name=arr3new>{{cite web |first=David |last=Eshel |url=http://www.aviationnow.com/aw/generic/story.jsp?id=news/awst/2010/02/08/AW_02_08_2010_p44-200503.xml&headline=Israel%20%20Upgrades%20Its%20Antimissile%20Plans&channel=defense |work=[[Aviation Week & Space Technology]] |title=Israel upgrades its antimissile plans |date=2010-02-12 |access-date=2010-02-13}}</ref>]]
SAM systems generally fall into two broad groups based on their guidance systems, those using [[radar]] and those using some other means.

Longer range missiles generally use radar for early detection and guidance. Early SAM systems generally used tracking radars and fed guidance information to the missile using [[radio control]] concepts, referred to in the field as [[command guidance]]. Through the 1960s, the [[semi-active radar homing]] (SARH) concept became much more common. In SARH, the reflections of the tracking radar's broadcasts are picked up by a receiver in the missile, which homes in on this signal. SARH has the advantage of leaving most of the equipment on the ground, while also eliminating the need for the ground station to communicate with the missile after launch.

Smaller missiles, especially MANPADS, generally use [[infrared homing]] guidance systems. These have the advantage of being "fire-and-forget", once launched they will home on the target on their own with no external signals needed. In comparison, SARH systems require the tracking radar to illuminate the target, which may require them to be exposed through the attack. Systems combining an infrared seeker as a [[terminal guidance]] system on a missile using SARH are also known, like the [[MIM-46 Mauler]], but these are generally rare.

Some newer short-range systems use a variation of the SARH technique, but based on [[laser]] illumination instead of radar. These have the advantage of being small and very fast acting, as well as highly accurate. A few older designs use purely optical tracking and command guidance, perhaps the best known example of this is the British ''[[Rapier (missile)|Rapier]]'' system, which was initially an all-optical system with high accuracy.

All SAM systems from the smallest to the largest generally include [[identification friend or foe|identified as friend or foe]] (IFF) systems to help identify the target before being engaged. While IFF is not as important with MANPADs, as the target is almost always visually identified prior to launch, most modern MANPADs do include it.

===Target acquisition===
[[File:JASDF Type91 SAM, in Alaska(USAF photo 080613-F-4127S-012).jpg|thumb|right|A JASDF soldier uses the optical sight on the Type 91 Kai MANPADS to acquire a mock airborne target. The prominent vertical metal devices on the left are the [[identification friend or foe|IFF antennas.]] ]]
[[File:USMC-090212-M-6603L-077.jpg|thumb|right|A [[U.S. Marine]] antiaircraft gunner aims his ''Stinger'' at a location indicated by a spotter.]]

Long-range systems generally use radar systems for target detection, and depending on the generation of system, may "hand off" to a separate tracking radar for attack. Short range systems are more likely to be entirely visual for detection.

Hybrid systems are also common. The [[MIM-72 Chaparral]] was fired optically, but normally operated with a short range early warning radar that displayed targets to the operator. This radar, the [[AN/MPQ-49 Forward Area Alerting Radar|FAAR]], was taken into the field with a [[Gama Goat]] and set up behind the lines. Information was passed to the ''Chaparral'' via a [[data link]]. Likewise, the UK's Rapier system included a simple radar that displayed the rough direction of a target on a series of lamps arranged in a circle. The missile operator would point his telescope in that rough direction and then hunt for the target visually.