Phalanx CIWS

Phalanx CIWS

Phalanx (Block 1A) live fire test aboard the USS Monterey in November 2008.
Type Close-in weapon system
Place of origin United States
Service history
In service 1980–present
Used by See operators
Wars Persian Gulf War
Production history
Designer General Dynamics (now Raytheon)
Manufacturer General Dynamics (now Raytheon)
Produced 1978[1]
Specifications
Weight 12,500 lb (5,700 kg), later models 13,600 lb (6,200 kg)[1]
Barrel length • Block 0 & 1 (L76 gun barrel): 60 in (1,500 mm)
• Block 1B (L99 gun barrel): 78 in (2,000 mm)[2]
Height 15.5 ft (4.7 m)
Crew Automated, with human oversight
Shell • Naval: Armor-piercing tungsten penetrator rounds with discarding sabots.
• Land: High-Explosive Incendiary Tracer, Self-Destruct.
Caliber 20×102 mm
Barrels 6-barrel (progressive RH parabolic twist, 9 grooves)
Elevation • Block 0: -10°/+80°
• Block 1: -20°/+80°
(Rate of elevation: 86°/sec for Block 0/1)
• Block 1B: -25°/+85°
(Rate of elevation: 115°/sec)[2]
Traverse • 150° from either side of centerline
(Rate of traverse: 100°/sec for Block 0 & 1, 116°/sec for Block 1B)[2]
Rate of fire 4,500 rounds/minute (75 rounds/second).
Muzzle velocity 3,600 ft/s (1,100 m/s)[2]
Effective firing range 2.2 mi (3.5 km)[2]
Maximum firing range Classified[1][3]
Main
armament
 1× 20 mm (0.79 in) M61 Vulcan 6-barreled Gatling cannon[4]
Guidance
system
 Ku-band radar and FLIR[5]

The Phalanx CIWS is a close-in weapon system for defense against anti-ship missiles. It was designed and manufactured by the General Dynamics Corporation, Pomona Division[4] (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.[6]

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.[7][8]

History

The Phalanx Close-In Weapons System (CIWS) was developed as the last line of automated weapons defense (terminal defense or point defense) against anti-ship missiles (AShMs or ASMs) and attacking aircraft, including high-g and maneuvering sea-skimmers. The first prototype system was offered to the U.S. Navy for evaluation on the USS King in 1973 and it was determined that additional improvements were required to improve performance and reliability. Subsequently, the Phalanx Operational Suitability Model successfully completed its Operational Test and Evaluation (OT&E) on board the USS Bigelow in 1977. The model exceeded operational maintenance, reliability, and availability specifications. Another evaluation successfully followed, and the weapon system was approved for production in 1978. Phalanx production started with orders for 23 USN and 14 foreign military systems. The first ship fully fitted out was the aircraft carrier USS Coral Sea in 1980. The Navy began placing CIWS systems on non-combatant vessels in 1984.

Design

The basis of the system is the 20 mm M61 Vulcan Gatling gun autocannon, used since 1959 by the United States military on various tactical aircraft, linked to a Ku-band radar system for acquiring and tracking targets. This proven system was combined with a purpose-made mounting, capable of fast elevation and traverse speeds, to track incoming targets. An entirely self-contained unit, the mounting houses the gun, an automated fire-control system and all other major components, enabling it to automatically search for, detect, track, engage, and confirm kills using its computer-controlled radar system. Due to this self-contained nature, Phalanx is ideal for support ships, which lack integrated targeting systems and generally have limited sensors. The entire unit has a mass between 12,400 and 13,500 lb (5,500 to 6,100 kg).

Upgrades

Rounds from a Mk-15 Phalanx CIWS from the guided-missile destroyer USS Mitscher (DDG 57) impact the ex-USNS Saturn (T-AFS-10) during a sinking exercise (SINKEX), 2010.

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.[9] 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.[9]

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.[10] The Block 1B is also used by other navies, such as Canada, Portugal, Japan, Egypt, Bahrain, and the UK.[11]

In May 2009, the US Navy awarded a $260 million contract to Raytheon Missile Systems to perform upgrades and other work on the Phalanx.[12]

Comparison with other CIWS

Comparison of some modern CIWS
Russia AK-630[13] United States Phalanx CIWS [14] Netherlands Goalkeeper CIWS Italy DARDO[15]
Weight 9,114 kg (20,093 lb) 6,200 kg (13,700 lb) 9,902 kg (21,830 lb) 5,500 kg (12,100 lb)
Armament 30 mm (1.2 in) 6-barreled GSh-6-30 Gatling Gun 20 mm (0.79 in) 6-barreled M61 Vulcan Gatling Gun 30 mm (1.2 in) 7-barreled GAU-8 Gatling Gun 40 mm (1.6 in) 2-barreled Bofors 40 mm
Rate of Fire 5,000 rounds per minute 4,500 rounds per minute 4,200 rounds per minute 600/900 rounds per minute
(effective/ flat-trajectory) Range 4,000 m (13,000 ft) 3,600 m (11,800 ft) 2,000 m (6,600 ft) 4,000 m (13,000 ft)
Ammunition storage 2,000 rounds 1,550 rounds 1,190 rounds 736 rounds
Muzzle velocity 900 m (3,000 ft) per second 1,100 m (3,600 ft) per second 1,109 m (3,638 ft) per second 1,000 m (3,300 ft) per second
Elevation −12 to +88 degrees −25 to +85 degrees −25 to +85 degrees −13 to +85 degrees
Traverse 360 degrees 360 degrees 360 degrees 360 degrees

Operation

The CIWS is designed to be the last line of defense against anti-ship missiles. Due to its design criteria, its effective range is very short relative to the range of modern ASMs, from 1 to 5 nautical miles (9 km). The gun mount moves at a very high speed and with great precision. The system takes minimal inputs from the ship, making it capable of functioning, despite potential damage to the ship. The only inputs required for operation are 440 V AC Three-phase electric power at 60 Hz and water (for electronics cooling). For full operation, including some non-essential functions, it also has inputs for true compass ship's heading and 115 V AC for the PASS subsystem.

A technician checks the radar transmitter and microwave assemblies of a Phalanx CIWS, most likely a Block 0. On the unit in the background, the search radar can be seen at the top left with the vertical, orange-peel shaped, tracking radar below it.

Radar subsystems

The CIWS has two antennas that work together to engage targets. The first antenna, for searching, is located inside the radome on the weapon control group (top of the white-painted portion). The search subsystem provides bearing, range, velocity, heading, and altitude information of potential targets to the CIWS computer. This information is analyzed to determine whether the detected object should be engaged by the CIWS system. Once the computer identifies a valid target (see details below), the mount moves to face the target and then hands the target over to the tracking antenna. The track antenna is extremely precise, but views a much smaller area. The tracking subsystem observes the target until the computer determines that the probability of a successful hit is maximized and then, depending on the operator conditions, the system will either fire automatically or will recommend fire to the operator. While firing, the system tracks outgoing rounds and 'walks' them onto the target.

U.S. Navy sailors load tungsten ammunition (white sabots at right) and off-load dummy ammunition (left).

Gun and ammunition handling system

The Block 0 CIWS mounts (hydraulic driven) fired at a rate of 3,000 rounds per minute and held 989 rounds in the magazine drum.[4] The Block 1 CIWS mounts (hydraulic) also fired at 3,000 rounds per minute with an extended magazine drum holding 1,550 rounds. The Block 1A and newer (pneumatic driven) CIWS mounts fire at a rate of 4,500 rounds per minute with a 1,550-round magazine. The velocity of the rounds fired is approximately 3,600 feet per second (1,100 m/s). The rounds are armor-piercing tungsten penetrator rounds or depleted uranium with discarding sabots. The Phalanx CIWS 20 mm rounds are designed to destroy a missile's airframe and make it unaerodynamic, thus keeping shrapnel from the exploding projectile to a minimum, effectively keeping collateral damage to a minimum. The ammunition handling system has two conveyor belt systems. The first takes the rounds out of the magazine drum to the gun; the second takes empty shells or non-fired rounds to the opposite end of the drum.

CIWS contact target identification

The CIWS does not recognize identification friend or foe, also known as IFF. The CIWS only has the data it collects in real time from the radars to decide if the target is a threat and to engage it. A contact has to meet multiple criteria for it to be considered a target. Some of the criteria are listed below:

A sailor sits at a CIWS Local Control Panel (LCP) during a general quarters drill.
  1. Is the range of the target increasing or decreasing in relation to the ship? The CIWS search radar will see contacts that are out-bound and discard them. The CIWS will engage a target only if it is approaching the ship.
  2. Is the contact capable of maneuvering to hit the ship? If a contact is not heading directly at the ship, the CIWS looks at its heading in relation to the ship and its velocity. It then decides if the contact can still perform a maneuver to hit the ship.
  3. Is the contact traveling between the minimum and maximum velocities? The CIWS has the ability to engage targets that travel in a wide range of speeds; however, it is not an infinitely wide range. The system has a target maximum-velocity limit. If a target exceeds this velocity, the CIWS will not engage it. It also has a target minimum-velocity limit. Any contact below that velocity will also not be engaged by the CIWS. The operator also has the option to adjust the minimum and maximum limits within the limits of the system.

There are many other subsystems that together ensure proper operation, such as environmental control, transmitter, mount movement control, power control and distribution, and so on. It takes six to eight months to train a technician to maintain, operate, and repair the CIWS.

Incidents

Drone exercise catastrophic accidents

On 10 February 1983, the USS Antrim was conducting a live-fire exercise off the East Coast of the United States using the Phalanx against a target drone. Although the drone was successfully engaged at close range, the target debris bounced off the sea surface and struck the ship. This caused significant damage and fire from the drone's residual fuel, which also killed a civilian instructor aboard this ship.[16][17]

On 11 October 1989, the USS El Paso was conducting a live-fire exercise off the East Coast of the United States using the Phalanx against a target drone. The drone was successfully engaged, but as the drone fell to the sea, the CIWS re-engaged it as a continued threat to the El Paso. Rounds from the Phalanx struck the bridge of the USS Iwo Jima, killing one officer and injuring a petty officer.[18]

Iraqi missile attack in 1991 Gulf War

On 25 February 1991, during the first Gulf War, the Phalanx-equipped frigate USS Jarrett was a few miles from the US battleship USS Missouri and the British destroyer HMS Gloucester. The ships were attacked by an Iraqi Silkworm missile (often referred to as the Seersucker), at which time the Missouri fired its SRBOC chaff. The Phalanx system on Jarrett, operating in the automatic target-acquisition mode, fixed on Missouri's chaff, releasing a burst of rounds. From this burst, four rounds hit Missouri which was two to three miles (about 5 km) from Jarrett at the time. There were no injuries.[19] A Sea Dart missile was then launched from Gloucester in a 'tail end' engagement; destroying the Iraqi missile as it passed between Gloucester and Missouri, achieving the first successful engagement of a missile by a missile during combat at sea.

JMSDF mounted Phalanx CIWS

Accidental downing of US aircraft by the Japanese destroyer Yūgiri

On 4 June 1996, a Japanese Phalanx accidentally shot down a US A-6 Intruder from the USS Independence that was towing a radar target during gunnery exercises about 1,500 miles west of the main Hawaiian island of Oahu. A Phalanx aboard the Asagiri class destroyer Yūgiri locked onto the Intruder instead of the target. Both pilots ejected safely.[20] A post-accident investigation concluded that the Yūgiri's gunnery officer gave the order to fire before the A-6 was out of the CIWS engagement envelope.[21][22]

21st century

Centurion C-RAM

Centurion C-RAM

Seeking a solution to constant rocket and mortar attacks on bases in Iraq, the United States Army requested a quick-to-field anti-projectile system in May 2004, as part of its Counter-Rocket, Artillery, Mortar initiative.[23] The end result of this program was 'Centurion'. For all intents and purposes, a terrestrial version of the Navy's CIWS, the Centurion was rapidly developed,[24] with a proof-of-concept test in November that same year. It began deployment to Iraq in 2005,[23][25] where it was set up to protect forward operating bases and other high-value sites in and around the capital, Baghdad.[26] Israel has purchased a single system for testing purposes, and was reported[27] to have considered buying the system to counter rocket attacks and defend point military installations. However, the swift and effective development and performance of Israel's indigenous Iron dome system has ruled out any purchase or deployment of Centurion.

Each system consists of a modified Phalanx 1B CIWS, powered by an attached generator and mounted on a trailer for mobility. Armed with a 20 mm M61A1 Gatling gun, the unit is capable of firing 4,500 20 mm rounds per minute.[6][28] In 2008, there were more than 20 CIWS systems protecting bases in the U.S. Central Command area of operations. A Raytheon spokesman told Navy Times that 105 attacks were defeated by the systems, most of those involved mortars. Based on the success of Centurion, 23 additional systems were ordered in September 2008.[29]

Like the naval (1B) version, Centurion uses Ku-band radar and FLIR[30] to detect and track incoming projectiles, and is also capable of engaging surface targets, with the system able to reach a minus-25-degree elevation.[30] The Centurion is reportedly capable of defending a 0.5 mi square area.[31] One major difference between the land- and sea-based variants is the choice of ammunition. Whereas naval Phalanx systems fire tungsten armor-piercing rounds, the C-RAM uses the 20 mm HEIT-SD (High-Explosive Incendiary Tracer, Self-Destruct) ammunition, originally developed for the M163 Vulcan Air Defense System.[24][32] These rounds explode on impact with the target, or on tracer burnout, thereby greatly reducing the risk of collateral damage should any rounds fail to hit their target.[24]<ref name="aviationweek.com"/

SeaRam

SeaRAM

Utilizing the armament of the RIM-116 Rolling Airframe Missile, and based on the mounting and targeting systems of the Phalanx, SeaRAM was developed in response to concerns about the performance of gun-based systems against modern, supersonic, sea-skimming, anti-ship missiles. Designed as a companion self-defense system to Phalanx,[33] the SeaRAM is equipped with an 11-cell RAM launcher, and provides defense at a longer range. Due to the common mounting, SeaRAM inherits the relatively easy installation characteristics of its gun-based sibling, with Raytheon stating that "[SeaRAM] fits the exact shipboard installation footprint of the Phalanx, uses the same power and requires minimal shipboard modification."[33] Currently in the trial stages, SeaRAM is fitted to the Independence Class Littoral Combat Ship.[33]

Operators

Map of Phalanx CIWS operators in blue

Current operators

Specifications (Block 1A/B)

Raytheon Missile Systems Phalanx Block 1B close-in weapon system (CIWS) on board the Royal Navy Type 45 destroyer HMS Daring.

Similar systems

References

Notes
  1. 1 2 3 4 "The US Navy – Fact File". Navy.mil. 2009-11-09. Retrieved 2010-04-13.
  2. 1 2 3 4 5 Tony DiGiulian (2010-06-16). "USA 20 mm Phalanx Close-in Weapon System (CIWS)". NavWeaps.com. Retrieved 2010-10-26.
  3. ↑ John Pike (2005-04-27). "MK 15 Phalanx Close-In Weapons System (CIWS)". Globalsecurity.org. Retrieved 2010-04-13.
  4. 1 2 3 4 Thomas, Vincent C. The Almanac of Seapower 1987 Navy League of the United States (1987) ISBN 0-9610724-8-2 p.191
  5. ↑ Archived October 7, 2009 at the Wayback Machine
  6. 1 2 "Murdoc online March 20, 2006 CIWS now does surface targets, too". Murdoconline.net. Retrieved 2010-04-13.
  7. ↑ "Spacewar.com". Spacewar.com. Retrieved 2010-04-13.
  8. ↑ "TELUS, news, headlines, stories, breaking, canada, canadian, national". Home.mytelus.com. Retrieved 2010-04-13.
  9. 1 2 "Raytheon Company: Phalanx". Raytheon.com. Retrieved 2010-04-13.
  10. ↑ Navy Overhauls Phalanx Ship Defense Weapon - Defensetech.org, 21 August 2013
  11. ↑ "Raytheon Awarded Phalanx 1B Upgrade Order for Royal Navy". Prnewswire.com. Retrieved 2010-04-13.
  12. ↑ Arizona Daily Star, May 16, 2009. "Navy Awards $260 Million In Additional Work On Ship Weapons System To Raytheon"
  13. ↑ "AK-630 Gatling Gun Close in Weapon System". Indian-military.org. 2010-03-12. Retrieved 2012-08-04.
  14. ↑ Dan Petty. "The US Navy – Fact File:". Navy.mil. Retrieved 2012-08-04.
  15. ↑ Tony DiGiulian. "Italy 40 mm/70 (1.57") Breda". Navweaps.com. Retrieved 2012-08-04.
  16. ↑ "USS Antrim (FFG 20)". Navysite.de. Retrieved 2012-08-04.
  17. ↑ "USS Antrim FFG-20". Historycentral.com. Retrieved 2012-08-04.
  18. ↑ Plunkett, A.J. (October 12, 1989). "Iwo Jima Officer Killed In Firing Exercise". Daily Press. Retrieved 2013-08-16.
  19. ↑ "Tab-H Friendly-fire Incidents". Gulflink.osd.mil. Retrieved 2010-04-13.
  20. ↑ Cable News Network. Japan apologizes for gunning down U.S. plane. June 4, 1996.
  21. ↑ The Virginian-Pilot. Human Error Cited In Downing Of Navy Plane By Japanese. October 24, 1996.
  22. ↑ Transcript of the DoD investigation of the incident
  23. 1 2 "Army C-RAM Intercepts 100th Mortar Bomb in Iraq". Defense-update.com. 2007-06-07. Retrieved 2010-04-13.
  24. 1 2 3 "Navy News, news from Iraq". Navy Times. 2005-06-27. Retrieved 2010-04-13.
  25. ↑ "First C-RAM joint intercept battery organizes for combat. – Free Online Library". Thefreelibrary.com. Retrieved 2010-04-13.
  26. ↑ http://www.timripley.co.uk/articles/jdw_uk_deploys_c_ram.pdf
  27. ↑ "BMD Focus: Barak dithered on Phalanx". Spacewar.com. Retrieved 2010-04-13.
  28. ↑ "Israel may buy rapid-fire cannon" Jerusalem Post Dec 20, 2007
  29. ↑ Analyst: DDGs without CIWS vulnerable. Navy Times. September 16, 2008
  30. 1 2
  31. ↑ 23-Apr-2009 13:20 EDT (2009-04-23). "A Laser Phalanx?". Defenseindustrydaily.com. Retrieved 2010-04-13.
  32. ↑ "Counter-RAM Systems Target Rockets". Aviation Week. 2009-08-27. Retrieved 2010-04-13.
  33. 1 2 3 Raytheon. SeaRAM datasheet. (PDF)
  34. 1 2 3 4 5 6 7 8 9 10 "Mk 15 Phalanx Block 0 / CIWS, Close-In Weapon System". Deagel.com. 2010-03-07. Retrieved 2010-04-13.
  35. ↑ "World Navies Today: india". Hazegray.org. 2002-03-24. Retrieved 2010-04-13.
  36. 1 2 3 4 5 "Mk 15 Phalanx Block 1B / CIWS, Close-In Weapon System". Deagel.com. Retrieved 2010-04-13.
  37. ↑ "INS Jalashwa". bharat-rakshak.com. Retrieved 2015-04-16.
  38. ↑ "Mexico Missile Boats". HAARETZ.com. 2003-12-23. Retrieved 2013-04-10.
  39. ↑ "Raytheon to deliver 9 Phalanx CIWS to Republic of Korea Navy". February 25, 2014.
  40. ↑ "World Navies Today: Thailand". Hazegray.org. 2002-03-25. Retrieved 2010-04-13.
  41. ↑ "FY97 Annual Report - PHALANX CLOSE-IN WEAPON SYSTEM (CIWS)". Globalsecurity.org. Retrieved 2016-01-05.

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