From Wikipedia, the free encyclopedia

The Aegis combat system is an integrated missile guidance system used by the United States Navy. It is both an integrated single ship system and a ship to ship network. It is also used by the Japanese Navy, Spanish Navy, and Norwegian Navy. The Royal Australian Navy and the South Korean Navy have selected the Aegis system for their new destroyers.

Contents 1 Development 2 Iran Air Flight 655 3 Aegis in other navies 3.1 Alleged Aegis clones 4 References 5 See also 6 External links

By the late 1960s, the U.S. Navy recognized that reaction time, firepower, and operational availability in all environments did not match the anti-ship missile threat. As a result, an operational requirement for an Advanced Surface Missile System (ASMS) was promulgated and a comprehensive engineering development program was initiated to meet that requirement. ASMS was re-named "Aegis" in December 1969 after the aegis, the shield of the Greek god Zeus.

The name is sometimes spelled AEGIS, supposedly an acronym for phrases such as "Advanced Electronic Guidance Information System." However, such attributions seem to be backronyms or fake etymologies. (It is also possible there has been some confusion with the EGIS software used by some AWACS aircraft.) The main manufacturer of the Aegis combat system, Lockheed Martin, makes no mention of it being an acronym.

The heart of the system is an advanced, automatic detect-and-track, multi-function three-dimensional passive electronically scanned array radar, the AN/SPY-1. Known as "the Shield of the Fleet", the Aegis high-powered (four megawatt) radar is able to perform search, tracking, and missile guidance functions simultaneously with a track capacity of over 100 targets at more than 100 nautical miles.^[1] The first Engineering Development Model (EDM-1) was installed in the test ship, USS Norton Sound, in 1973. The Aegis system uses missile uplink using the AN/SPY-1 radar for midcourse guidance of Standard missiles during engagements, but still requires the AN/SPG-62 radar for terminal guidance. This means that with proper scheduling of intercepts, a large number of targets can be engaged simultaneously.

The computer-based command-and-decision element is the core of the Aegis combat system. This interface makes the Aegis combat system capable of simultaneous operation against a multi-mission threat: anti-air, anti-surface and anti-submarine warfare. The Aegis system is being enhanced to act in a Theater Missile Defense role, to counter short- and medium-range ballistic missiles of the variety typically employed by rogue states (see Aegis Ballistic Missile Defense System).

The Navy built the first Aegis-equipped cruisers using the hull and machinery designs of Spruance-class destroyers. The first cruiser of this class was the Ticonderoga, which uses two twin-armed Mark-26 missile launchers, fore and aft. The commissioning of the sixth ship of the class, the Bunker Hill opened a new era in surface warfare as the first Aegis ship outfitted with the Martin Marietta Mark-41 Vertical Launching System (VLS), allowing a wider missile selection, more firepower, and survivability. The improved AN/SPY-1B radar went to sea in the Princeton, ushering in another advance in Aegis capabilities. The Chosin introduced the AN/UYK-43/44 computers, which provide increased processing capabilities.

In 1980, a destroyer was designed using an improved sea-keeping hull form, reduced infrared, and radar cross-section and upgrades to the Aegis Combat System. The first ship of the Arleigh Burke class, the USS Arleigh Burke, was commissioned in 1991. Because the Aegis system dominates the ship's architecture, ships equipped with it are sometimes mistakenly called Aegis class ships.

Flight II of the Arleigh Burke class, introduced in 1992, incorporates improvements to the SPY radar, and to the Standard missile, active electronic countermeasures, and communications. Flight IIA, introduced in 2000, added a helicopter hangar with one anti-submarine helicopter and one armed attack helicopter. The Aegis program has also projected reducing the cost of each Flight IIA ship by at least $30 million.

The Aegis system was involved in an incident in which USS Vincennes shot down Iran Air Flight 655 in 1988 resulting in 290 civilian fatalities.

Using the Aegis system, Vincennes's captain believed the Iran Air Airbus A300B2 was a much smaller Iran Air Force F-14A Tomcat jet fighter descending on an attack vector, when in fact the Airbus was climbing on its normal civilian flight path.^[2] This was attributed to the fact that the Aegis radar system had temporarily lost Flight 655 and reassigned its track number to a F-14A Tomcat fighter that it had previously seen. The Vincennes fired two missiles at the aircraft, later found to be Iran Air Flight 655.

• Australia, under its Sea 4000 project to acquire three Air Warfare Destroyers, decided in August 2004 that the Aegis warfare system would be the core of the combat system for the new ships. In 2007 the Australian government is expected to decide between the Arleigh Burke design and the Alvaro de Bazán class design.
• Japan operates four Kongo-class destroyers of a modified Arleigh Burke design. Two improved units knowns as the Atago class are currently under construction.
• Norway is procuring five ships of Spanish manufacture which include a U.S. sourced Aegis system integrated onto the ships, as the Fridtjof Nansen class. The first unit of this type, Fridtjof Nansen, was launched on June 3, 2004.
• South Korea is building Aegis variants of its KDX destroyers, called KDX-III.
• Spain is currently operating five Alvaro de Bazán class Aegis frigates, with at least four in commission.

India has recently been offered the Aegis system.

• People's Republic of China currently operates two Type 052C Lanzhou guided missile destroyers, supposedly derived from Aegis.

• CIWS

• AEGIS Weapon System MK-7 in the FAS Military Analysis Network.

• DDG-51 ARLEIGH BURKE-class in the FAS Military Analysis Network.

• AN/SPY-1. The Warfighter Encyclopedia. Warfighter Response Center (2003-10-08). Retrieved on 2006-08-10..

• AEGIS Weapon System MK-7. Jane's Information Group (2001-4-25). Retrieved on 2006-08-10..

• "MK 7 AEGIS FIRE CONTROL SYSTEM RADAR", FIRE CONTROLMAN, VOLUME 02--FIRE CONTROL RADAR FUNDAMENTALS. US NAVY. Retrieved on 2006-08-10. .