Goalkeeper CIWS

From Free net encyclopedia

Image:Goalkeeper.jpg Goalkeeper is a Dutch close-in weapon system, the purpose of which is to defend a ship against incoming missiles and ballistic shells. The system consists of an autocannon and an advanced radar which tracks incoming fire, determines its trajectory, then aims the gun and fires in a matter of seconds. The system is fully automatic, needing no human input once activated. The name comes from the Soccer position. The system is made by Thales Navy Netherlands, and over 50 have been produced. The system can also be deployed to protect airfields.

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Development

Development of the system began in 1975 with Signaal (now Thales Nederland) working with General Electric, who supplied the GAU-8 gun. A prototype, the EX-83 was first demonstrated to the Royal Netherlands Navy in 1979. The system entered service with the Royal Netherlands Navy in 1980. Goalkeeper is fitted in two Royal Navy vessels; HMS Illustrious and HMS Invincible.

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Description

The system first acquires a target using the 2D X-Band search radar, which can track up to 18 targets at once. The engagement radar is then slewed to the heading indicated by the search radar. The engagement radar operates in both X-Band and Ka-Band, this enables the engagement radar to use the search radars signal to find the target quickly without additional searching, also data from the X-Band and Ku-Band return signals can be compared to increase resistance to ECM and clutter. The engagement radar is also backed up by an optical system.

The GAU-8/A Avenger 30 mm gun, as used by the A-10 Thunderbolt II was selected for the system, primarily because although the muzzle velocity and range are similar to the M61 Vulcan the projectiles are much heavier (430 grams compared to 100 grams). This is critical because supersonic missiles that are damaged may still have enough momentum to hit the ship—the only way to ensure the protection of the ship is either detonate the warhead of the missile or obliterate the missile.

The systems reaction time to a Mach 2 sea-skimming missile from automatic detection to kill is reported to be 5.5 seconds with the engagement starting at a range of 1500 m and ending with a kill at 300 m.

The Chinese appear to have developed a very similar weapon, possibly a copy, called the Type 730.

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Specifications

Gun: GAU-8/A Avenger/77 30 mm seven-barrel Gatling gun.
Height: 3.71 m (above deck) 6.2 m (including deck pentration).
Weight: 6372 kg (mount with ammunition) 9902 kg (total).
Elevation +85 to -25 degrees at 80 degrees/sec.
Traverse 360 degrees at 100 degrees/sec.
Muzzle velocity: 1109 m/s (MPDS round).
Rate of fire: 70 or 75 round/second (4200 round/minute).
Maximum burst size: 300 rounds.
Ammunition: 1190 linkless (HEI,API,TP,MPDS) rounds in a below deck magazine.
Reload time: 9 minutes (loading is done below deck)
Weapons range: 350 to between 1500 and 2000 meters dependant on ammunition.
Search radar: X-band / linear array. Beamsize 1.5 degrees horizontal, 60 degrees vertical. Rotates at 60 rpm. Range approx 30 km.
Engagement radar: X-band and Ka-Band monopulse cassegrain.
Optical system: TV
Kill distance: 500 meters
Cost: £8 Million

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Comparison to Phalanx

The Phalanx CIWS system is another system that is widely used in the same role, there are several key differences between the two systems:

Goalkeepers projectiles are much larger (30 mm versus 20 mm) and have greater Kinetic energy.
Goalkeeper is twice as expensive as the Phalanx.
Phalanx can be welded to any section of deck and plugged in, while Goalkeeper requires significant 'deck penetration' and integration.
Phalanx can only track and engage one target at a time, while Goalkeeper can track 18 targets and switch to engage the greatest threat.
Both weapons have similar maximum ranges, however Goalkeepers kill distance is reportedly a slightly further (500 to 350 meters compared to 300 meters for the Phalanx).
Phalanx ammo drum is mounted directly on the gun, the Goalkeeper is reloaded from below deck.

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