Close-in Weapon System Development The sinking of the Israeli destroyer Eilat in October 1967 by SS-N-2 `Styx' (qv) anti-ship missiles created great concern in the United States Navy which was at that time conducting operations off the Vietnamese coast. The concern was increased by the knowledge that the Russians had a submarine-launched missile, SS-N-7 `Starbright' (qv), which would further reduce reaction times. Consequently in 1968 a quick reaction feasibility study requirement was issued and the following year a contract was awarded to General Dynamics, Pomona (now Hughes Missile) for a closed-loop fire-control system. The concept was demonstrated at White Sands, New Mexico, in 1970 and as a result, prototypes designated Mark 90 fire-control system and Mark 72 gun mountings, were developed and delivered in January 1973 with one installed in the `Farragut' class `fleet escort' (later destroyer) USS King (DLG 10, later DDG 41) between August 1973 and March 1974. However, doubts were expressed about the capability of the system and with the end of the Indochina War, naval funding became subject to greater restriction. Problems were also encountered but in July 1974 six more systems were ordered as operational suitability models. In November 1974 a remotely operated system was installed in the hulk of the destroyer Cunningham and used in lethality testing against a wide variety of missiles including Walleye laser-guided bombs until February 1976. Another system was installed in the destroyer USS Bigelow (DD 942) for testing in a severe ECM environment. In July 1977 the system, dubbed Mark 15 Close-In Weapon System (CIWS) and named Phalanx, was approved for service use with a full production contract awarded to General Dynamics in September 1979. The first systems entered service in April 1980 in the aircraft carrier USS America (CV 66) and its use was subsequently extended to all surface warships of frigate size and above, all major amphibious warfare vessels and many important auxiliaries. The first export customer was Saudi Arabia and the system entered service in September 1981 with the commissioning of the corvette Badr. In February 1987 GE Aerospace, Ordnance Systems (now Lockheed Martin, Armament Systems Division) was awarded a second source contract for Phalanx. The Phalanx has been continually improved especially with software but in the early 1980s the threat from high-angle diving missiles led to the first major hardware improvement. A version capable of dealing with high-angle diving threats was delivered in prototype form as Block 1 in 1985 and installed in the cruiser USS Biddle (CG 34). Limited production of what became Block 1 Baseline 0 began in late 1985 (it was formally approved in March 1986) and the system entered service in the battleship USS Wisconsin (BB 64) in October 1988. Subsequently the definitive model appeared as Block 1 Baseline 1 and was phased into production from FY88 and approved for full production two years later. Production of Block 0 ceased in 1987 and in the US Navy, and many of its allies, many Block 0 systems have been, or are scheduled to be, upgraded to Block 1 standard. Plans also existed to produce a follow on system, provisionally designated CIWS-2000 and later Block 2 with full-scale development anticipated from late 1991. However, there were considerable doubts both within the US Navy and Congress about the value of a next generation gun system. Congress refused funding in January 1988 until the Signaal Goalkeeper (qv) had been evaluated, and in 1991 the programme was abandoned in favour of further incremental improvements to the Phalanx. In January 1994 Hughes Missile began to integrate improved sensors and controls to produce the Block 1 Baseline 3 version with surface engagement capability. Plans now exist for Block 1 Baseline 4 with better sensors and processing and this is scheduled to enter service in 1997. Early in 1994 Devenport Management Ltd (DML) won a Pds2.4 million contract to upgrade five Phalanx systems to Block 1 standards. The contract included a similar option for another six systems. In April 1995 it was revealed at the US Navy League convention that Hughes and Signaal will develop a high-energy laser-based CIWS based upon the Phalanx mounting. It is planned to enter service by 2005 to replace Phalanx and Goalkeeper. Hughes was also teamed with Loral Defense Systems - Akron (now Lockheed Martin Tactical Systems Company) on a similar project with at sea trials in the drone test ship Decatur in the Summer of 1995. Description The Mark 15 CIWS is a `closed-loop' (that is, tracking both the target and the stream of rounds) weapon system designed to provide the innermost layer of defence against anti-ship missiles. It consists of the Mark 16 weapon group, the Mark 339 local and Mark 340 remote-control panels as well as a remote indicator panel. The Mark 16 weapons group is based upon a barbette assembly with electronics cabinet (called an `enclosure') attached to the rear. The mount and train drive assembly are on top of it and hold the 20 mm gun assembly with the fire-control radar and servo assembly above it. The group occupies a 5.5 m{2} space on the deck and is on a 150 mm thick platform but requires no deck penetration. The Baseline 0 group is 3.1 m long, 4.7 m high and weighs 5.24 tonnes while the Baseline 1 group has the same length but is about 5 m high and weighs 6.17 tonnes. The barbette contains the hydraulic and transmitter power supplies, the environmental control unit and the seawater heat exchanger. The system uses 31.75 kg of seawater per minute for cooling, the water being supplied from ship systems. The Phalanx has demonstrated the ability to operate for 30 minutes without cooling before shutting down.
The gun assembly is suspended between the supports of the mount and
train drive assembly. It consists of a 20 mm M61A1 Vulcan
Gatling-principle gun in an open box assembly suspended beneath which
is a cylindrical magazine and feeding mechanism. The rounds are moved
in a belt from the lower end of the magazine's front along its right
side to enter the lower part of the gun on the left side (when viewed
from the front) through a chute conveyor system. The ammunition
magazine takes up to 30 minutes to reload. The M61A1 Vulcan is a
six-barrelled weapon capable of phenomenally high rates of fire and is
powered by a T48 electric gun drive. The 1.52 m long barrels are made
of chromium-moly-vanadium and weigh 7.93 kg with nine rifling grooves
featuring a 7° twist extending for 1.42 m.
The Lockheed Electronics AN/UPS-2 radar is a 12 to 18 GHz (J-band) pulse Doppler sensor with a vertical tracking antenna at the front and a search antenna at the top. The shared transmitter, the receiver and servo mechanisms are all in the same housing. The system is capable of search, detection, threat evaluation, acquisition, track and fire modes which can be conducted automatically through a digital computer with manual override. In search mode the radar uses unambiguous Doppler/ambiguous range and switches PRF to achieve range resolution in three range-coverage zones. It uses unambiguous Doppler/ambiguous range as well as a derived search range to acquire the target as well as bearing and speed to search the range, angle, speed envelope provided by the search radar. Angle tracking is monopulse with PRF switching to track across blind ranges. Target data is correlated according to range, range rate and angular position relative to the mounting. When the target is evaluated as a threat the tracking antenna, which has a rate integrating gyro, is adjusted to the target's elevation so there will be no delay between target handover and track acquisition. An error signal between the gun's existing position and the target's location provides gun control. The Mark 339 local-control panel is attached to the ship's structure in a shock-proof mounting and includes all the controls required for operational maintenance and emergency operational control in the event of battle damage. The Mark 340 remote-control panel is used for target allocation through a multiple battery control system which supervises up to four mountings. It operates in conjunction with the individual Mark 339 panels. The bridge-mounted remote indicator panel is used to display the status of the ship's Mark 16 weapons groups and there are two below-deck gun-control panels. In addition to the normal, `bolt-on', configuration Phalanx may also be installed in two other specialised configurations for environmental or operational reasons. The low-profile Electronics Enclosure (ELX) has the barbette lowered into a carrier sponson. The deck-mounted maintenance enclosure installation features the barbette in a metal housing which enhances mounting accessibility to maintenance personnel. The electronics enclosure tends to be a little distance from the barbette while the train platform is raised to allow the installation of a waterproof seal. These enclosures are normally associated with Block 0 mountings and were introduced when sea corrosion problems were encountered. Phalanx is normally set up to scan a particular sector and will automatically engage fast air targets unless the `hold fire' button is pressed. Targets can be detected at 3 n miles (5.6 km) and acquired at 2.3 n miles (4.3 km). When the gun fires, the radar tracks the centroid of six outgoing projectiles, predicts their point of closest approach to the target and corrects the aim of the following bursts. This technique uses variable PRF with selected spectral frequency line tracking to measure the stream of projectiles' angular error. Firing usually begins at 1 n mile (1.85 km) with a maximum probable kill at 460 m. System reaction time is reported to be 3 seconds. Although designed for autonomous missile engagement, Phalanx targets may be designated by other ship sensors through the command and weapon control system. It may also be used for surface-to-surface engagements through another fire-control system or an optical/electro-optical designator. In SSDS (qv) the Phalanx radar can be used to cue the RIM-116A Rolling Airframe Missile (qv). Two major versions and four models of Phalanx have been planned: Block 0 Description This version features a 16-bit Control Data Corporation (CDC, now Computer Development Inc or CDI) Model 469E parallel word, general purpose computer with AN/AYK-14 style core memory and has a 980-round magazine and the hydraulically driven gun drive provides a rate of fire of 3,000 rds/min. The search radar uses a horizontal antenna slaved to a vertical gyro to compensate for deck pitching. It has only a limited elevation coverage and in evaluating threats it is turned in the target's direction. Block 1 Description Baseline 0: This model also has the CDC/CDI Model 469E computer together with a new search radar antenna consisting of a four-plate, back-to-back array to provide nominal hemispheric coverage. The introduction of Very Large Scale Integrated (VSLI) circuitry, especially in the transmitter mode control unit, greatly improved reliabilty. The gun assembly features a positive ceasefire function which matches burst lengths to target characteristics and to ensure that when firing ceases there are no live rounds in the breech. The whole mounting weighs 6.18 tonnes. Baseline 1: The gun assembly in this model has a pneumatic gun drive which increases rate of fire to 4,500 rds/min and a 1,470-round magazine with tungsten penetrators replacing the depleted uranium ones from circa 1990. The radar has improved sensitivity. Baseline 2: This version was to have had a new loading system with a second ammunition drum on the electronics enclosure feeding the main magazine. It was also scheduled to receive a Thomson-CSF radar transmitter. The radar was cancelled on cost grounds. Instead it received a higher order computer language and the ability to interface with Aegis or SSDS while a muzzle brake was also added to the gun. It entered service in FY95. Block 1A Description This mounting, which was scheduled for fleet release in 1996, has a 32-bit CDI Mips-based R3000 RISC microprocessor and Ada-language software to introduce Kalman filtering for gun aiming. It also incorporates the ability to interface with SSDS. Block 1B Description
This is an upgraded Block 1A and adds a surface engagement mode
capability with reduced gun dispersion (by lengthening the gun barrels
to 482 mm and introducing a new mounting for the gun) and a new
electromagnetic interference mitigation feature into the radar.
Added to the system is a Pilkington Optronics HDTI (High Definition
Termal Imager) and SRT Electro-Optics video tracker as well as manual
acquisition controls. The HDTI, which is mounted on the left of the
radome, weighs 6 kg and operates in the 8 to 12 µm range with fields
of view of 9 x 6° and 3 x 2°. Contraves Inc will supply the
stabilisation system while Hughes Missile Systems will provide the
engagement controller. The system is scheduled to enter service in
FY98. Status By June 1994 some 792 Phalanx systems had been delivered or ordered, including some 250 for export, of which 346 were dedicated Block 1. Hughes Missile Systems Company/General Dynamics produced 734 of the total while Lockheed Martin/General Electric produced 58 Block 1s. Phalanx is in service with, or ordered for, Gearing and Amazon class ships in Pakistan Navy have this system . SPECIFICATIONS :
Gun Mounting
Weight: 5.42 t (Block 0), 6.18 t (Block 1) COMPANY NAME : Hughes Missile Systems Company
|
