GPS stands for Global Positioning System. Users of a global positioning system can calculate their location anywhere on the earth. There are currently two "public" GPS systems. The NAVSTAR system is owned by the United States and is managed by the Department of Defense. The GLONASS system is owned by the Russian Federation. While both NAVSTAR and GLONASS systems are global positioning systems, the NAVSTAR system is often referred to (in the U.S., anyway) as the GPS because it was generally available first. Nevertheless, both systems are GPS systems and the reader should keep this in mind.
The NAVSTAR system is managed by the NAVSTAR GPS Joint Program Office, located at Los Angeles Air Force Base. The civilian point of contact for NAVSTAR information is the U.S. Coast Guard's Navigation Center (NAVCEN). The NAVCEN provides system status information in the form of a document called a Notice Advisory to Navstar Users (NANU). Civil users have input to NAVSTAR system issues through the Civil GPS Service Interface Committee (CGSIC), which is organized by the Coast Guard.
The point of contact for GLONASS information is the Russian Space Forces' Coordinational Scientific Information Center (CSIC). The CSIC presents system status information in the form of a document called a Notice Advisory to Glonass Users (NAGU).