|Country of origin||United States|
|Precision||Fire control quality three-dimensional data|
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.
- First letter (installation) - S = Water (surface ship)
- Second letter (type of equipment) - P = Radar
- Third letter (purpose) - G = Fire Control or Searchlight Directing
- 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.