Aegis Combat System

The Aegis Combat System is an American integrated naval weapons system, which uses computers and radars to track and guide weapons to destroy enemy targets. It was developed by the Missile and Surface Radar Division of RCA, and it is now produced by Lockheed Martin.

Initially used by the United States Navy, Aegis is now used also by the Japan Maritime Self-Defense Force, Spanish Navy, Royal Norwegian Navy, Republic of Korea Navy, and Royal Australian Navy, and is planned for use by the Royal Canadian Navy. As of 2022, a total of 110 Aegis-equipped ships have been deployed, and 71 more are planned (see operators).

Aegis BMD (Ballistic Missile Defense) capabilities are being developed as part of the NATO missile defense system.

The word "Aegis" is a reference that dates back to Greek mythology, with connotations of a protective shield, as the Aegis was the buckler (shield) of Zeus, worn by Athena.

The Aegis Combat System (ACS) implements advanced command and control (command and decision, or C&D, in Aegis parlance). It is composed of the Aegis Weapon System (AWS), the fast-reaction component of the Aegis Anti-Aircraft Warfare (AAW) capability, along with the Phalanx Close In Weapon System (CIWS), and the Mark 41 Vertical Launch System. Mk 41 VLS is available in different versions that vary in size and weight. There are three lengths: 209 in (5.3 m) for the self-defense version, 266 in (6.8 m) for the tactical version, and 303 in (7.7 m) for the strike version. The empty weight for an 8-cell module is 26,800 lb (12,200 kg) for the self-defense version, 29,800 lb (13,500 kg) for the tactical version, and 32,000 lb (15,000 kg) for the strike version, thus incorporating anti-submarine warfare (ASW) systems and Tomahawk Land Attack Cruise Missiles (TLAM). Shipboard torpedo and naval gunnery systems are also integrated.

AWS, the heart of Aegis, comprises the AN/SPY-1 Radar, MK 99 Fire Control System, Weapon Control System (WCS), the Command and Decision Suite, and Standard Missile family of weapons; these include the basic RIM-66 Standard, the RIM-156 Standard ER extended range missile, and the newer RIM-161 Standard Missile 3 designed to counter ballistic missile threats. A further SM-2 based weapon, the RIM-174 Standard ERAM (Standard Missile 6) was deployed in 2013. Individual ships may not carry all variants. Weapons loads are adjusted to suit assigned mission profile. The Aegis Combat System is controlled by 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 SPY high-powered (6 megawatt) radar is able to perform search, tracking, and missile guidance functions simultaneously with a track capacity of well over 100 targets at more than 100 nautical miles (190 km). However, the AN/SPY-1 Radar is mounted lower than the AN/SPS-49 radar system and so has a reduced radar horizon.

The Aegis system communicates with the Standard missiles through a radio frequency (RF) uplink using the AN/SPY-1 radar for mid-course update missile guidance during engagements, but still requires the AN/SPG-62 fire-control 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 (C&D) element is the core of the Aegis Combat System and came from the Naval Tactical Data System (NTDS) threat evaluation and weapons assignment (TEWA) function. This interface makes the ACS capable of simultaneous operation against almost all kinds of threats.