Sentry gun

Weapon that automatically aims and fires at targets

A sentry gun is a weapon that is automatically aimed and fired at targets that are detected by sensors. The earliest functioning military sentry guns were the close-in weapon systems point-defense weapons, such as the Phalanx CIWS, used for detecting and destroying short range incoming missiles and enemy aircraft, first used exclusively on naval assets, and now also as land-based defenses.

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