(GLObal NAvigation Satellite System-GLObalnaya NAvigatsionnaya Sputnikovaya Sistema) A satellite-based radio navigation system run by the Russian Ministry of Defense. It uses 21 MEO satellites and three spares. Similar to the global positioning system (GPS) in the U.S., GLONASS enables 3D positioning anywhere on earth within 100-150 meters for the public and 10-20 meters for the military. The first satellite was launched in 1982, and the system became operational in 1993, although the full complement of satellites was not completed until 1995. See GPS, Galileo and GNSS.