Aegis combat system
The
Aegis combat system is an integrated
missile guidance system used by the
United States Navy.
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
phased 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 miles.
[.] 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 1994, 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 mistakenly 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 [
1]. Following this disaster improvements were made to the Aegis system, particularly to the crew interface [
2].
The Aegis system correctly identified and reported flight 655's civilian IFF (
identification, friend or foe) number, and that it was only flying at 385
knots airspeed; however the crew of
Vincennes misinterpreted this information. The
U.S. Navy and
U.S. Senate investigations were unable to determine which crew member initiated the report that the plane was an F-14, and further recommended Aegis operator training procedures be improved.
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Japan operates four
Kongo class destroyers of a modified
Arleigh Burke design. Two improved units knowns as the
Atago class are currently under construction.
*
Spain is currently operating five
Alvaro de Bazán class Aegis
frigates, with at least four in commission.
*
Norway is procuring five units of Spanish design and manufacture, 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.
*
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.
*
People's Republic of China has launched two Luyang II
guided missile destroyers, which are undergoing sea trials. These carry combat systems alleged to have been at least partially
reverse engineered from stolen Aegis technology.[
3]
*
AEGIS Weapon System MK-7 in the FAS Military Analysis Network.
*
DDG-51 ARLEIGH BURKE-class in the FAS Military Analysis Network.
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