The GPS control segment is a global network of ground facilities that track the satellites, monitor their transmissions, perform analyses, and send commands and data to the constellation.
WASHINGTON – The scheduled December launch of the first GPS 3 satellite has been described by the U.S. Air Force as the “start of a new era.” It’s an entirely new satellite design, and the first GPS to go to space aboard a SpaceX rocket. It’s also a test for how the Air Force manages the transition to a new ground control system that has been plagued by delays and will not be ready until 2021.
The Air Force decided to stick with the launch schedule and get satellites in orbit while work continues on the development of the GPS 3 next-generation operational control system, known as OCX. To fill the gap, satellite manufacturer Lockheed Martin is upgrading the legacy control systems so the Air Force can fly and test the new satellites.
Col. Steven Whitney, director of the Air Force GPS Directorate, said the first GPS 3 will interact with “elements” of OCX Block 0 but the satellite will be operated with the existing GPS control segment that is being upgraded by Lockheed Martin. Raytheon is the primary contractor for OCX. The GPS 3 spacecraft acquisition and on-orbit checkout will be done from Lockheed Martin facilities.
In anticipation of a late delivery of OCX, the Air Force in 2016 put Lockheed Martin under contract to develop a “contingency” upgrade for the GPS operational control segment and M-Code early use. The M-Code is the more powerful GPS 3 signal for military users that is more secure against jamming or spoofing. Lockheed said the upgraded ground system will be ready by May 2019 and the M-Code early use software by 2020.
As many as seven GPS 3 satellites could be in orbit before the development of OCX is completed. The disparity between the launch and the ground control equipment schedules was flagged by congressional auditors as a “risk factor” in the program. The Air Force and Raytheon renegotiated the schedule for OCX Block 1 in April 2017 and the target completion date is June 2021. Block O, the launch and checkout system, was delivered in September 2017.
A lot is riding on OCX, estimated to cost $6 billion. In the Pentagon’s $1.4 billion budget request for the GPS program in 2019, more than $500 million is for OCX.
As each new GPS 3 satellite is launched into orbit, it will undergo tests before the Air Force decides if it can be integrated into the existing constellation. The upgraded legacy ground control system will support GPS 3, as well as the GPS 2R, 2R-M and 2F satellites. GPS 3s would augment the current operational constellation of 31 GPS satellites.
The GPS control segment is a global network of ground facilities that track the satellites, monitor their transmissions, perform analyses, and send commands and data to the constellation.
The next-generation OCX was designed first and foremost to improve the cybersecurity of the ground segment. The system will have the highest cybersecurity protection of any military space system, Raytheon Vice President and OCX Program Manager Bill Sullivan told SpaceNews. “OCX implements layered security. It’s like an onion, with layers of security controls. That’s difficult to implement in legacy systems,” he said. “We can integrate new types of security controls as threats evolve.”
Sullivan said OCX Block 0 will “support readiness activities for the upcoming GPS 3 launch in December and for early orbit operations.”
Until OCX Block 1 is available, the updated legacy ground system will be used to integrate GPS 3 satellites into the operational constellation and to “start testing some of GPS 3’s advanced capabilities even earlier,” Lockheed Martin’s program manager Johnathon Caldwell said last week in a news release.
OCX meanwhile is proceeding forward to meet the June 2021 deadline. A significant event this summer was a successful qualification test for the monitoring station receivers, Sullivan said.
The GPS network has 16 monitoring sites that provide global coverage. Six are owned by the Air Force and 10 by the National Geospatial Intelligence Agency. They require sophisticated receivers to track GPS satellites as they pass overhead. The stations collect signals, measurements, and atmospheric data, and feed observations to the master control station.
A favorable qualification test “positions us to start deploying those monitoring station receivers in 2019,” said Sullivan.
OCX software development has been accelerated and should be completed in 2019, Sullivan said. The company has a team of programmers developing, testing and turning around fixes using an Amazon Web Services cloud platform.
Raytheon’s OCX contract will be up for an extension in June 2021 when Block 1 is completed. “At that point have an option to sustain that system after delivery,” said Sullivan. “We do expect the Air Force to exercise that option before June 2021.”