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The Global Positioning System, or GPS, is a network of orbiting satellites that broadcasts a continuous stream of precise position details to earth, allowing GPS receivers to determine users’ exact locations across the world.

GPS Modernization

The current GPS system consists of two key segments: space and ground control. The space segment includes the constellation of multiple satellites currently on orbit, while the control segment consists of the ground-based stations that are responsible for tracking, monitoring, and updating of the satellites. As part of an historic modernization effort Raytheon will deliver the full enhanced ground control segment, commonly referred to as GPS Next-Generation Operational Control System or GPS OCX.


Together with next-generation satellites, GPS OCX will provide improved accuracy of the current system and will be able to fly more than twice as many satellites. Those additional satellites will increase coverage in hard-to-reach areas such as urban canyons and mountainous terrain.

GPS OCX has implemented 100 percent of the Department of Defense’s information assurance standards without waivers, giving it the highest level of cybersecurity protections of any DoD space-ground system. The cyber-secure system will have improved accuracy with better international availability as well as globally deployed modernized receivers with anti-jam capabilities.

Important Milestones

Deliverables for the entire GPS OCX system are divided into three blocks: Block 0, Block 1 and Block 2. Block 0 delivery took place in the fall of 2017, enabling it to support the first launch of modernized GPS III satellites in 2018. In December of 2018, the US Air Force successfully launched the first next-generation GPS III satellites from Cape Canaveral Florida using the GPS OCX Launch and Checkout System (LCS). The mission successfully completed the Launch and Early Orbit phase of the Mission on January 1, 2019. Since then, the LCS has been used to launch three GPS satellites and all four have been handed off to U.S. Air Force operations squadron.

In early 2021, the Ground System Simulator received accreditation. The Ground System Simulator (GSYS) mimics critical tasks of GPS ground control, including constellation management of more than 40 satellite simulations, replicating the command and control of 17 monitor stations, four ground antennas, as well as simulating the entire satellite lifecycle from launch to disposal.

Block 1 will provide full operational capability to include control of both legacy and modernized satellites and signals. Block 2, delivered concurrently with Block 1, adds operational control of the new international L1C and modernized Military Code signals.