Directions 2018: Resiliency key to new GPS

December 1, 2017  - By
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By Col. Steven Whitney
Director, Global Positioning Systems Directorate

Col. Steven Whitney (Photo: USAF)

Col. Steven Whitney (Photo: USAF)

The most discussed theme in the U.S. Air Force space community over the last year has been “resiliency.” But what does that actually mean, and how can the Air Force increase resiliency in space?

The GPS Directorate took these questions to heart and thought long and hard about resiliency in our Positioning, Navigation, and Timing (PNT) service. I am pleased to report that we have made significant progress in the past year in our quest to bring a new generation of PNT technology to reality.

More importantly, our investments in space, ground, and user equipment developments are bringing real, tangible benefits towards providing a more resilient PNT service worldwide. We stand on the cusp of delivering modernized civil and military GPS signals which provide critical pieces to the puzzle.

Farther into the future, the Air Force is already exploring new, emerging technologies and capabilities to even further advance the robustness of the GPS enterprise, with the vision that GPS will always remain the “Gold Standard” for the worldwide PNT community.

Resiliency Begins with Signals

Modernized GPS signals will be the first piece of the puzzle for an overall resilient PNT solution. The community has long anticipated the beginning of the multi-GNSS era.

The GPS Directorate has embraced this future with a new L1C signal, designed cooperatively from the ground up to be interoperable with international satellite navigation systems. The signal design will greatly improve GPS reception in cities and other challenging environments.

Another important GPS signal was introduced with our GPS IIF satellites. The L5 signal is designed specifically to meet the demanding requirements for safety-of-life transportation and other high-performance applications.

This signal is broadcast in a radio-frequency band reserved exclusively for aviation safety services to ensure it has optimal spectrum protection. Together, these two new additions greater improve PNT resilience for civil users around the globe.


“The need to improve cyber security and protection quite honestly cannot wait until delivery of the Next-Generation Operational Control System (OCX). To that end, the Directorate has focused on high payoff updates for the existing operational system.”


Other measures already improve resiliency by leveraging existing signals. For example, the L2C signal, when combined with L1 C/A in a dual-frequency receiver, will enable ionospheric error correction and improve positioning and timing accuracy.

For the military, the directorate has been focused on bring Military Code (M-code) into operations. The M-code signal features advanced anti-jam, anti-spoof, and encryption features that will ensure resilient and dependable PNT solutions for the United States and its allies.

The rollout of an operational M-code capability involves all segments of the GPS enterprise, and while it has been a long time in coming, the GPS Directorate made big strides this year (see “2017 in Review”). I will touch on the progress we are making in each of our development programs.

Resiliency in Space

The GPS space segment is the next step towards a more resilient PNT architecture. Our constellation remains robust and healthy, albeit aging, with 31 operational satellites providing worldwide coverage at the time of this article. The GPS III satellites will bring additional robustness with increased power and accuracy over previous generations of satellites.

We made big strides towards launching the first GPS III satellite in 2018, and just as importantly, production is in full swing on the rest of the ten satellites. I am incredibly proud of the entire government and contractor team that is meticulously acquiring, assembling, and testing these complex machines.

GPS IIIF. Farther into the future, the directorate is preparing for the GPS III follow-on program. The Air Force will be adding important new resiliency capabilities, with added signal flexibility via a reprogrammable, digital payload and increased anti-jam support to theater with a Regional Military Protection capability. Over the coming years as the follow-on GPS III satellites join the constellation, they will revolutionize GNSS with the full complement of operational L1C, L2C, L5 and M-code signals.

Resiliency in Control Segment

As important as the satellites are, the control segment is just as integral to the overall resiliency of the GPS enterprise. The need to improve cyber security and protection quite honestly cannot wait until delivery of the Next-Generation Operational Control System (OCX).

To that end, the directorate has focused on high payoff updates for the existing operational system.

For example, we acquired and deployed software-based GPS monitor station receivers, known as Monitor Station Technology Improvement and Capability (MSTIC) receivers, to replace the aging fleet of existing monitor-station receivers.

The functionality and expandability of the MSTIC receiver design will facilitate adding further capabilities such as M-code signal monitoring, and even civil L1C, L2C, and L5 signal monitoring.

The GPS Directorate also deployed a new cybersecurity monitoring suite to enhance cyber defenses. This new suite is in operation today at the GPS Master Control Station (MCS).

Beyond just improving our cyber protection, the Air Force has also stepped out on several OCX off-ramps to support the launch and operation of the GPS III satellites and mitigate risk of further OCX delays.

The Contingency Operations (COps) program modifies the existing Operational Control System (OCS) to allow the first GPS III satellites to join the operational constellation. The Air Force also initiated a companion program, M-code Early Use (MCEU) to further update OCS to provide limited M-code operations.

Together, these two programs provide critical interim steps towards fielding a more resilient constellation.


See also by Col. Steven Whitney,

Directions 2018: The GPS year in review


The OCX program provides the ultimate cyber protection and assurance needed for the GPS enterprise. After emerging from program recertification this year, the program has focused heavily on improved software system engineering and embracing software industry best practices, such as adopting DevOps and greater software automation.

The program has even leveraged Amazon Web Services’ Gov’t Cloud capability to provide more responsive development and test environments. While the program has a long ways to go, the government and prime contractor, Raytheon, are committed to delivery to ensure a robust and secure ground infrastructure.

User Equipment: Final Piece

The final piece of the resiliency puzzle for military customers is our user equipment segment. The directorate has made big strides in delivering the first set of modernized receiver cards for the Military GPS User Equipment (MGUE) Increment 1 program.

These advanced cards will enable platforms across the U.S. Department of Defense to leverage the new M-code signal, providing a tremendous boost in both anti-jam and anti-spoof capability.

They will also provide the latest in cryptography to ensure secure, robust protection for the United States and its allies.

Down the road, the Department of Defense is evaluating additional capabilities and platforms for the MGUE Increment 2 program.

Currently envisioned to address precision guided munitions, space receivers, and a modernized handheld unit, the Increment 2 program will be laying out an acquisition plan in this coming year to further adoption of M-code signals throughout the military.

A consideration for the future of user equipment will be exploring processing multi-GNSS signals. While no decisions have been made, multi-GNSS could offer opportunities for even additional resiliency.

Final Thoughts

This is an exciting time for the GPS enterprise.

We stand on the cusp of a new generation of capabilities that will usher in a huge increase in PNT resiliency and robustness. I am astounded at the quality of work that is presented at the many GNSS and PNT conferences around the world, and it is both exciting and humbling to see the community continuing to innovate ways to increase accuracy, integrity, availability, continuity, and performance.

Likewise, I am honored to lead the men and women of the GPS Directorate as we strive to deliver on our commitments and find new, innovative ways to provide robust and resilient PNT to the world.

This dedicated team is poised and ready to lead us into the future, and we look forward to working with the entire community to continue delivering the GPS “Gold Standard” in space-based PNT.

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