Aegis combat system
The Aegis combat system, named for the mythological aegis shield, is a United States Navy weapons system. The heart of the system is an advanced, automatic detect and track, multi-function phased-array radar, the AN/SPY-1. This high-powered (four megawatt) radar is able to perform search, track and missile guidance functions simultaneously with a track capacity of over 100 targets. The first Engineering Development Model (EDM-1) was installed in the test ship, USS Norton Sound (AVM-1) in 1973.
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.
The Navy built the first Aegis cruisers using the hull and machinery designs of Spruance-class destroyers. The commissioning of USS Bunker Hill (CG-52) opened a new era in surface warfare as the first Aegis ship outfitted with the Vertical Launching System (VLS), allowing greater missile selection, firepower and survivability. The improved AN/SPY-1B radar went to sea in USS Princeton (CG-59), ushering in another advance in Aegis capabilities. USS Chosin (CG-65) introduced the AN/UYK-43/44 computers, which provide increased processing capabilities.
In 1980, a smaller ship 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 DDG-51 class, Arleigh Burke, was commissioned on the Fourth of July, 1991. The DDG-51 class was named after a living person, the legendary Admiral Arleigh Burke, the most famous destroyerman of World War II.
DDG-51s were constructed in flights, allowing technological advances during construction. Flight II, introduced in FY 1992, incorporates improvements to the SPY radar and the Standard missile, active electronic countermeasures and communications. Flight IIA, introduced in FY 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.