AN/SPY-1

The AN/SPY-1 is a US naval radar system manufactured by Lockheed Martin. The array is a passive electronically scanned system and is a key component of the Aegis Combat System. The system is computer controlled, using four complementary antennas to provide 360 degree coverage. The system was first installed in 1973 on the USS Norton Sound and entered active service in 1983 as the SPY-1A on USS Ticonderoga. The -1A was installed on ships up to CG-58, with the -1B upgrade first installed on Princeton in 1986. The upgraded -1B(V) was retrofitted to existing ships from CG-59 up to the last, CG-73.

The SPY-1D was first installed on Arleigh Burke in 1991. It is a variant of the -1B to fit the Arleigh Burke class. The -1D(V), the Littoral Warfare Radar, was an upgrade introduced in 1998 for high clutter near-coast operations, where the earlier "blue water" systems were especially weak.

The SPY-1F is a smaller version of the 1D designed to fit frigates. It is not used by the US Navy, but has been exported to Norway. The origin of the SPY-1F can be traced back to the Frigate Array Radar System (FARS) proposed to the German Navy in the 1980s.

The SPY-1K is the smallest version of the radar currently offered, based on the same architecture as the 1D and 1F. It is intended for use on very small vessels such as corvettes, where the SPY-1F would be too large. As of 2007, none are in service, although the radar is incorporated into the design of the yet-unbuilt AFCON Corvette.