The Phalanx Close-In Weapon System is a rapid-fire, computer-controlled, radar-guided gun system designed to defeat anti-ship missiles and other close-in air and surface threats. The Phalanx CIWS was designed and manufactured by the General Dynamics Corporation, Pomona Division (now a part of Raytheon). Consisting of a radar-guided 20 mm Gatling gun mounted on a swiveling base, the Phalanx has been used by multiple navies around the world, notably the United States Navy on every class of surface combat ship, by the British Royal Navy in its older escorts (where weight limits the use of the heavier Dutch Goalkeepers 30 mm CIWS), by the United States Coast Guard aboard its Hamilton-class and Legend-class cutters, and the navies of 16 allied nations.
A land based variant, known as C-RAM, has recently been deployed in a short range missile defense role, to counter incoming rockets and artillery fire.
Because of their distinctive barrel-shaped radome and their automated nature of operation, Phalanx CIWS units are sometimes nicknamed “R2-D2” after the famous droid character from the Star Wars films.
Due to the continuing evolution of both threats and computer technology, the Phalanx system has, like most military systems, been developed through a number of different configurations. The basic (original) style is the Block 0, equipped with first-generation, solid-state electronics and with marginal capability against surface targets. The Block 1 (1988) upgrade offered various improvements in radar, ammunition, computing power, rate of fire, and an increase in maximum engagement elevation to +70 degrees. These improvements were intended to increase the system’s capability against emerging Russian supersonic anti-ship missiles. Block 1A introduced a new computer system to counter more maneuverable targets. The Block 1B PSuM (Phalanx Surface Mode, 1999) adds a forward-looking infrared (FLIR) sensor to allow the weapon to be used against surface targets. This addition was developed to provide ship defense against small vessel threats and other “floaters” in littoral waters and to improve the weapon’s performance against slower low-flying aircraft. The FLIR’s capability is also of use against low-observability missiles and can be linked with the RIM-116 Rolling Airframe Missile (RAM) system to increase RAM engagement range and accuracy. The Block 1B also allows for an operator to visually identify and target threats.
As the system model manager, the U.S. Navy is in the process of upgrading all their Phalanx systems to the Block 1B configuration. All Phalanx systems in use by the U.S. Navy are scheduled to be upgraded to Block 1B by the end of FY 2015. In addition to the FLIR sensor, the Block 1B incorporates an automatic acquisition video tracker, optimized gun barrels (OGB), and Enhanced Lethality Cartridges (ELC) for additional capabilities against asymmetric threats such as small maneuvering surface craft, slow-flying fixed and rotary-winged aircraft, and unmanned aerial vehicles. The FLIR sensor improves performance against anti-ship cruise missiles, while the OGB and ELC provide tighter dispersion and increased “first-hit” range; the Mk 244 ELC is specifically designed to penetrate anti-ship missiles with a 44-percent-heavier tungsten penetrator round and an aluminum nose piece. Another system upgrade is the Phalanx 1B Baseline 2 radar to improve detection performance, increase reliability, and reduce maintenance. It also has a surface mode to track, detect, and destroy threats closer to the water’s surface, increasing the ability to defend against fast-attack boats and low-flying missiles; the Baseline 2 radar upgrade is to be installed on all U.S. Navy Phalanx system-equipped vessels by FY 2019. The Block 1B is also used by other navies, such as Canada, Portugal, Japan, Egypt, Bahrain, and the UK.
In May 2009, the US Navy awarded a $260 million contract to Raytheon Missile Systems to perform upgrades and other work on the Phalanx.