GPS Operational Control Segment


OCS provides Command and Control (C2) and Launch/Early Orbit, Anomaly, Resolution and Disposal Operations (LADO) capabilities for the Block II satellites. OCS also enables Selective Availability/Anti-Spoof Module (SAASM) capability in GPS User Equipment, as well as contingency recovery operations, over-the-air key distribution and rekeying capability.



In 1996 the OCS contract was awarded to Boeing Space & Intelligence Systems for performance through 2012. OCS was designed to allow the GPS system to evolve over time. Each element was updated to meet the major objectives of the OCS program. Architecture Evolution Plan (AEP) Version 5.2.1 and LADO Release 1 replaced the GPS legacy launch and satellite command and control systems in 2007. These were followed by AEP Version 5.2.2 and LADO Release 2 in 2008 which provided an initial GPS IIF capability. These were updated in 2010 with AEP Version 5.5 and LADO Release 2.8.3 to launch the first GPS IIF space vehicle in May 2010 and to enable SAASM. The OCS was upgraded in 2012 with AEP Version 5.8 to allow it to work with the new SAASM Mission Planning System located at the Joint Space Operations Center at Vandenberg AFB. The sustainment of OCS was recompeted and awarded to Lockheed Martin Information Systems and Global Solutions in January 2013.  



OCS consists of a worldwide network of satellite operations centers, ground antennas and monitor stations that are used to command and control DoD’s largest satellite constellation. 


OCS is divided into these major elements:

  • A command and control system for the navigation and timing mission (also known as the AEP system)

  • A command and control system for the LADO mission

  • An Integrated Mission Operations Support Center for archiving space vehicle telemetry

  • Four GPS Ground Antennas and six GPS monitoring stations

  • A GPS System Simulator to support system testing and a high-fidelity ops crew trainers


OCS is operated by the 2nd Space Operations Squadron (2 SOPS), located at Schriever Air Force Base, Colorado. 2 SOPS performs the global precision, navigation and timing mission 24 hours a day, 7 days a week. 19 SOPS, an Air Force Reserve unit, also based at Schriever Air Force Base, augments 2 SOPS and handles the LADO mission on an as-needed basis. Design of the OCS is driven by the need to maintain near continuous contact of every satellite in the GPS constellation.



The OCS Program has three major objectives:

  • Modernize existing GPS ground segment by replacing the aging mainframe based launch and satellite command and control systems with modern commercial off-the-shelf-based client-server systems

  • Deliver the capability to fly the next-generation of GPS satellites – GPS IIF

  • Provide necessary upgrades to enable the new security features inherent in SAASM-capable GPS UE


OCS is much more reliable and easier to maintain than the old legacy systems. This is demonstrated by the number of problem reports being fixed over time and the significant decrease in number of days needed to deliver each software build. This results in solid savings to Government in terms of lower maintenance costs. The OCS also uses graphic user interfaces to enhance operational efficiency, a modular architecture that simplifies system upgrades and a distributed local area network for redundancy.  


PRIME CONTRACTOR:  Lockheed Martin Information Systems and Global Solutions (IS&GS)


(Current as of April 2018))