Editing Surface-to-air missile (section)

===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.