Missile guidance refers to a variety of methods of guiding a missile

Missile

Though a missile may be any thrown or launched object, it colloquially almost always refers to a self-propelled guided weapon system.-Etymology:The word missile comes from the Latin verb mittere, meaning "to send"...

 or a guided bomb

Guided bomb

A guided bomb is a precision-guided munition intended to precisely hit a specific target, and to minimize damage to things other than the target....

 to its intended target. The missile's target accuracy is a critical factor for its effectiveness. Guidance systems improve missile accuracy by improving its "Single Shot Kill Probability" (SSKP), which is part of combat survivability calculations associated with salvo combat model

Salvo combat model

The salvo combat model provides a mathematical representation of missile battles between modern warships. It was developed by Wayne Hughes at the U.S. Naval Postgraduate School in Monterey . The salvo model describes the basic elements of modern missile combat in a very simple way...

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These guidance technologies can generally be divided up into a number of categories, with the broadest categories being "active," "passive" and "preset" guidance.