AN/SPG-55

The AN/SPG-55 was a tracking / illumination radar for Terrier and RIM-67 Standard missiles (SM-1ER/SM-2ER). It was used for target tracking and Surface-to-air missile guidance on numerous ships including Kitty Hawk-class aircraft carriers,Belknap-class cruisers, Leahy-class cruisers and Farragut class destroyers. It was also used on the nuclear-powered single units USS Long Beach (CGN-9), USS Bainbridge (CGN-25) and USS Truxtun (CGN-35). The SPG-55 was part of the Mk 76 missile fire control system.

Name
The designation "AN" stands for "Army-Navy" while "SPG" is not an acronym, but part of the MIL-STD-196E Type Designation System:
 * First letter (installation) - S = Water (surface ship)
 * Second letter (type of equipment) - P = Radar
 * Third letter (purpose) - G = Fire Control or Searchlight Directing

Variants

 * AN/SPG 55 - Original version supported Beam riding Terrier missiles.
 * AN/SPG 55A - Supported Beam-riding and homing Terrier missiles
 * AN/SPG 55B - Supported Beam-riding and homing Terrier missiles as well as newer Standard missiles.