AN/SPY-3

The AN/SPY-3 is a radar manufactured by Raytheon and designed for both blue-water and littoral operations.

Ancestry
The Aegis battle management system began with the AN/SPY-1 radar, intended to deal with an aircraft threat. AN/SPY-2 is an additional Aegis system, which extends the Aegis system sensors to be capable of ballistic missile defense.

Technology
AN/SPY-3 is the first US shipboard Active Electronically Scanned Array (AESA) system. It operates in both the X-band and S-band radar frequencies .

While it can perform most functions in either frequency band, for functions such as horizon search (anti-sea skimmer) and precision track (for fire control) the band can be selected to account for current atmospheric conditions, target characteristics, and other factors such as anomalous and multipath propagation. It has a single 6-faced antenna that can share the two available bands.

X-band functionality (8 to 12 GHz frequency range) is optimal for minimizing low-altitude propagation effects, narrow beam width for best tracking accuracy, wide frequency bandwidth for effective target discrimination, and the target illumination for SM-2 and Evolved Sea Sparrow Missiles (ESSM). Using the S-band is advantageous for search, operation in all forms of weather, and a narrow beam width for target tracking and resolution.

The system uses commercial off the shelf (COTS) computers and has reduced manning requirements for operation and maintenance. A number of operation and maintenance functions can be completely automated.

Deployment
The system will be introduced in the new Zumwalt-class destroyers and Gerald R. Ford-class aircraft carriers. It is also under consideration for retrofit to existing ships (USS Makin Island (LHD-8), Nimitz-class aircraft carriers, and San Antonio-class amphibious transport docks. Other installation candidates are the LH(X) future ship class.