The Global Positioning System (GPS) is a satellite-based positioning and navigation system that is funded and operated by the United States Department of Defense. Although originally developed for use by the U.S. military, GPS now supports thousands of civilian users worldwide and is employed in a wide range of applications. This technical note focuses on the use of GPS for telecommunications network timing and synchronization. The following sections describe the GPS system, how GPS calculates and transmits its timing signals, and how GPS timing is used in networks. Lastly, potential National Security/Emergency Preparedness (NS/EP) implications are discussed.
National Communications System Technical Notes, v.6 n.2, August 1999