The System: OCX Contract Pending
August 31, 2009 By: Alan Cameron GPS WorldWith a planned initial operational date in 2013, the GPS Advanced Control Segment (OCX) will improve GPS accuracy, integrity, availability, and continuity for military and civilian users around the world, and provide more efficient functionality to GPS operators, maintainers, and analysts. A final down-select by the U.S. Air Force (USAF) Space and Missile Systems Center to one of two contractor teams, led respectively by Northrop Grumman and Raytheon, is expected by the end of September. GPS World spoke to project leads from each team. A longer version of the interviews can be read here.
Northrop Grumman. According to Steve Bergjans, GPS OCX vice president and program manager for Northrop Grumman, the OCX effort represents a major modernization investment by the Air Force, with two critical capabilities:
- A service-oriented architecture with rapid insertion capability for new mission content
- An information assurance approach that provides cyber-secure connections to the Global Information Grid for net-centric operations.
“The fundamentals of navigating satellites, sampling signals through monitoring stations, those remain unchanged. What is different is the recognition that users require assured access to precision PNT, with more interactive concepts between user and control segment than are currently available.
“Interference of all kinds will require a more active interaction between the control segment and the user who may be affected.”
“We have looked at civil-oriented cases. One in particular, a recent occurrence of an interferer disrupting civil access to GPS signal, raised questions about how OCX will collaborate with FAA, DHS, and Coast Guard, to continue assuring civil access to the signal.
“What’s revolutionary about our vision for OCX is its service-oriented architecture, with modern software designed explicitly for net-centricity, to operate safely on authorized networks, so we can expose data, and get real-time feedback from users. Modularity will also facilitate rapid capability insertion.
“Thus, the net-centric concept of operations: more sensor data on local GPS performance and feedback from users, back to the control segment. Collaboration between users and control segment to resolve any issues. This in turn requires a strong information assurance design to ensure security and reliability.”
Raytheon. Bob Canty, vice president of GPS OCX and program manager for Raytheon, characterized the conceptual starting point for OCX as separating the GPS control segment from the space segment, after they had been connected for a number of years. “The government decision to split the control segment from space is very similar to why most companies made information technology (IT) a separate function. IT technologies were evolving so rapidly and became so foundational to execution success that specialized skills were needed to execute effectively. The GPS Wing saw the same need for specialized expertise on GPS OCX. By de-coupling the two segments, you also have the added benefit of inserting new operational features faster. From a ground perspective, you can bring capability into operations much more rapidly. Operational capability insertion becomes less dependent on space timelines.”
Canty stressed “time-certain delivery: the ability to deliver a control segment on time to satisfy the first GPS III launch in May 2014. It’s imperative that OCX has an overall programmatic approach to meet the first launch of GPS III. Our programmatic and technical solution is focused on a low-risk approach to satisfying the schedule requirement, and bring into operations as soon as possible new capabilities to enable L2C, M-code, L5, and L1C. Some of this capability is on orbit, or will be on orbit soon, but are not being brought into operations because of the current ground segment limitations. Today the GPS system is essentially being operated in a IIA-plus mode. When OCX gets delivered, it will enable all the capabilities inherent in IIR, IIR-M, and IIF vehicles, as well as IIIA. The current AEP system does not have the capability to provide these enhanced system capabilities.
“Our second focus is an architecture that can evolve to handle both foreseen and unforeseen changes as GPS evolves. We do not want to lock into a design that requires significant modification to incorporate new functions and technologies. Raytheon doesn’t build build space platforms but we do build control segments for every space provider and every type of payload. We leverage 40 year of control segment experience into our OCX flexible architecture solution — and Raytheon technologies developed on WAAS, the only GPS accredited safety-of-life implementation.
IIR-21(M) Rises
The U.S. Air Force successfully launched the last of eight modernized GPS IIR satellites built by Lockheed Martin Navigation Systems on August 17. It is expected to be set healthy for navigation users in September.
GPS IIR-21(M) joins the constellation of 30 operational satellites on-orbit; it will assume plane E, slot 3 position, replacing space vehicle number 40.
The Block IIR-M series includes a modernized antenna panel for increased signal power to receivers on the ground; two new military signals for improved accuracy, enhanced encryption, and anti-jamming; and a second open-access civil signal on a different frequency.
Next Up. The Air Force expects to launch the first of the IIF satellites, built by Boeing, in early 2010. The first block of GPS IIIA satellites is reported on track for 2014. The Lockheed program team recently completed the Preliminary Design Review (PDR) phase and is now in the midst of the Critical Design Review (CDR) phase.
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