Goalkeeper CIWS

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Goalkeeper CIWS on a British Invincible class aircraft carrier

Goalkeeper is a Dutch close-in weapon system, which defends ships 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 football/soccer position. The system is made by Thales Navy Netherlands. The system can also be deployed to protect airfields.

1 Development
2 Description
- 2.1 Target selection
- 2.2 Target engagement
3 Specifications
4 Comparison to Phalanx
5 Operators
6 External links

[edit] 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.

[edit] Description

[edit] Target selection

Goalkeeper has two radar sub-systems; search and track, which operate in conjunction with one another to identify and prioritise targets before engaging the highest priority.

The 2D I band search radar, which can track up to 18 targets at once, generates a threat picture which the gun system uses to identify threats and prioritise. Once a target has been prioritised the engagement radar is slewed to the target bearing indicated by the search radar. The tracking radar operates in both I band and K band to enable quick acquisition on the threat bearing. Data from both the I band and K band return signals indicate target range and can be used to identify, and respond to the use of, electronic countermeasures (ECM). The dual band system also reduces the effect of clutter, which can mask the target at low altitude. A camera system on the assembly provides a visual fallback for the system operator.

Target hit by Goalkeeper

[edit] Target engagement

The GAU-8/A Avenger 30 mm gun, as used by the A-10 Thunderbolt II, was selected for the system. The 30mm round has a greater mass than the M61 Vulcan used in Phalanx so that it has greater stopping power despite the similar muzzle velocity and range.

The 30mm round has a discarding nylon sleeve, or sabot, with a 21mm sub-calibre tungsten penetrator. The nylon sabot reduces barrel wear.

The tracking radar is capable of monitoring the line of fire and commanding minor adjustments.

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 system's reaction time to a Mach 2 sea-skimming missile like the Russian SS-N-22 Sunburn from automatic detection to kill is reported to be 5.5 seconds with the firing synchronised to start the engagement at a range of 1500 m and ending with a kill at 300 m.

[edit] Specifications

Gun: GAU-8/A Avenger 30 mm seven-barrel Gatling gun.
Height: 3.71 m (above deck) 6.2 m (including deck penetration).
Weight: 6,372 kg with 1,190 rds of ammunition (above deck), 9,902 kg (total).
Elevation +85 to −25 degrees at 80 degrees/sec.
Muzzle velocity: 1,109 m/s (MPDS round).
Turret Speed 360° in 3.8 seconds
Rate of fire: 70 rounds/second (4,200 rounds/minute).
Maximum burst size: 300 rounds.
Ammunition: 1,190 linkless (HEI, API, TP, MPDS, FMPDS) rounds in a below-deck magazine.
Reload time: 9 minutes (loading is done below deck)
Weapons range: 350 to between 1,500 and 2,000 meters dependent on ammunition.
Search radar: I band / linear array. Beamsize 1.5 degrees horizontal, 60 degrees vertical. Rotates at 60 rpm. Range approx 30 km.
Engagement radar: I band and K band monopulse cassegrain.
Optical system: TV
100% Kill distance: 500 meters
Cost: 16 million euros

[edit] Comparison to Phalanx

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

Goalkeeper's 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's ammo drum is mounted directly on the gun, while the Goalkeeper is reloaded from below deck.
Phalanx can only track and engage one target at a time, while Goalkeeper can track 18 targets and switch to engage the greatest threat.^{[citation needed]}
Both weapons have similar maximum ranges, however Goalkeeper's kill distance is reportedly slightly further (350 to 500 meters compared to 300 meters for the Phalanx).