The Aegis weapons system is a surface-to-air integrated weapons system. It is designed to defend the fleet against any airborne threat. The heart of the Aegis system is the AN/SPY-1 Phased-array radar system coupled with the AN/UYK-1 high-speed computer system. This combination is able to detect incoming missiles or aircraft, sort them by assigning a threat value, assign on-board Standard surface-to-air missiles, and guide the missiles to their targets. Aegis can track up to 100 targets at any given time. The radar panels are flat structures, mounted to give 360 degree coverage around the ship. These are an improvement over the old rotating type of radar in that there are no moving parts. The old rotating radar covered ONLY the area they were scanning. Phased arrays switch rapidly and cover the entire range around the ship in milliseconds.
The Versions (baselines):
For more than 40 years, the US Navy has developed systems and tactics to protect itself from air attacks. Since the end of World War II, several generations of anti-ship missiles have emerged as the air threat to the fleet. The first combatant ship sunk by one of these missiles was an Israeli destroyer in October 1967, hit by a Soviet built missile. The threat posed by such weapons was reconfirmed in April 1988 when two Iranian surface combatants fired on US Navy ships and aircraft in the Persian Gulf. The resulting exchange of anti-ship missiles led to the destruction of an Iranian frigate and corvette by US built Harpoon missiles. Modern anti-ship missiles can be launched several hundred miles away. The attacks can be coordinated, combining air, surface and subsurface launches, so that the missiles arrive on target almost simultaneously.
The US Navy's defense against this threat has continued to rely on the winning strategy of defense in depth. Guns were replaced in the late fifties by the first generation of guided missiles in their ships and aircraft. By the late sixties, these missiles continued to perform well, but it was recognized that reaction time, firepower, and operational availability in all environments did not match the threat. To counter this, 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 (after the mythological shield of Zeus) in December 1969.
The Aegis system was designed as a total weapon system, from detection to kill. The heart of the AEGIS systems is an advanced, automatic detect and track, multi-functional 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 capability of over 100 targets. The first Engineering Development Model (EDM-1) was installed in the test ship, USS NORTON SOUND (AVM 1) in 1973.
AEGIS is currently carried aboard 2 types of ships. The TICONDEROGA-class cruisers were the first. These ships are often fitted with 2 MK 41 VLS. They can carry up to 122 missiles of all types, including Tomahawk, Standard and SLAM. These ships carry a "full" AEGIS System. The second type of ship is the ARLEIGH BURKE-class destroyer. The AEGIS System carried aboard these ships is slightly less capable than the full AEGIS. These ships carry the same complement of missiles as the cruisers.
Currently there are four ship classes in the world equipped with the AEGIS Combat System:
-The ARLEIGH BURKE-class
-The F-100 frigates