2013-11-07 2014-02-04 Specification Required Unassigned Global Positioning System (GPS) a system of satellites that use spread-spectrum transmission, operated by the US military for commercial and military applications gps L1, L2, L1C, L2C, L5 "Navstar GPS Space Segment/Navigation User Interface," ICD GPS-200, Apr 2000. Galileo a system of satellites that operate in the same spectrum as GPS, operated by the European Union for commercial applications galileo L1, E5A, E5B, E5A+B, E6 GJU, "Galileo Open Service Signal In Space Interface Control Document (SIS ICD)", May 2006.