- Ballistic missile defense : A combination of sensors, command and control systems, and missile/warhead kill mechanisms that protect a region, or, in the case of the U.S., theaters of operations as well as the nation proper.
- Ballistic Missile Early Warning System : U.S. Air Force system for tracking ballistic missile trajectories over the north polar regions
- AN/FPS-49 : Mechanically steerable radar with a large parabolic antenna, operating in the VHF frequency spectrum, which was the initial tracking component of the Ballistic Missile Early Warning System; replaced by the UHF AN/FPS-92
- AN/FPS-85 : First operational U.S. phased array radar, used for space surveillance and submarine-launched ballistic missile detection; operates in the UHF frequency band; located at Eglin Air Force Base
- AN/FPS-115 : Add brief definition or description
- AN/FPS-120 : Add brief definition or description
- AN/FPS-123 : Add brief definition or description
- AN/FPS-126 : Add brief definition or description