"The Federal Radionavigation Plan (FRP) reflects the official radionavigation policy and planning for the Federal Government. The FRP covers both terrestrial and space-based, common-use, Federally operated radionavigation systems. These systems are sometimes used in combination with each other or with other systems. Systems used exclusively by the military are covered in the Chairman, Joint Chiefs of Staff (CJCS) Master Positioning, Navigation, and Timing Plan (MPNTP). The plan does not include systems that mainly perform surveillance and communication functions. The policies and operating plans described in this document cover the following radionavigation systems: 1. Global Positioning System (GPS) 2. Augmentations to GPS 3. Long Range Navigation (Loran) 4. Very High Frequency (VHF) Omni-directional Range (VOR) 5. Distance Measuring Equipment (DME) 6. Tactical Air Navigation (TACAN) 7. Instrument Landing System (ILS) 8. Microwave Landing System (MLS); Aeronautical Nondirectional Radiobeacons (NDB)."
U.S. Coast Guard: http://www.uscg.mil/