The AN/SPG-51 is an American tracking / illumination fire-control radar for RIM-24 Tartar and RIM-66 Standard missiles.

It is used for target tracking and Surface-to-air missile guidance as part of the Mk.

[4] Aircraft tracking is based on monopulse radar utilizing Pulse-Doppler radar signal processing in MK 74 MOD 14 and MK 74 MOD 15.

It provides illumination for bistatic radar operation associated with missile guidance in all configurations.

Older systems rely on conical scanning rather than monopulse.