The "Phalanx Close-In Weapons System":[https://en.wikipedia.org/wiki/Phalanx_CIWS] is a modern last line of defense system, generally used on warships but available land-based as well. A radar-aimed autonomous 6-barrel 20mm gatling autocannon fires bursts at up to 4,500 rounds per minute to disable or destroy incoming threats including missiles and attack aircraft.