When the global positioning system (GPS) becomes unreliable, it can bring aviation operations to a halt. MITRE outlined a process any U.S. airport can use to plan its emergency response to a GPS disruption event and minimize its impact.
Beyond the Signal: Helping Airports Develop Robust Emergency Plans for GPS Disruptions
Soon, airports throughout the United States will have a best-practices guide they can use to prepare for a GPS disruption event, thanks to more than two years of MITRE research, in collaboration with aviation stakeholders at two of the nation’s airports.
The U.S. aviation system relies heavily on GPS, so disruptions of this vital source of position, navigation, and timing information can temporarily cripple aviation operations at airports.
That reality was brought home in 2022, when two separate GPS interference events disrupted air traffic at U.S. airports. The first, which occurred in Denver in January 2022, lasted 33 hours. The second happened nine months later, in Texas’s Dallas–Fort Worth area, causing disruptions to air traffic for more than three days.
After the Denver event, the Aviation Cyber Initiative—tri-chaired by representatives from the Federal Aviation Administration (FAA) and the departments of Defense and Homeland Security—asked MITRE to develop a concept of operations (CONOPS) to help airports plan for GPS disruption events.
By the time the second event struck in Texas, MITRE—operator of the FAA’s federally funded R&D center (FFRDC)—had a plan drafted and was looking for a major hub airport willing to test it. Dallas Fort Worth International Airport volunteered.
“The CONOPS we developed is a high-level view of how to manage the whole event, from detection to compiling a common operating picture and disseminating that information to all the people and entities who needed it,” says Sean McCourt, project lead. “With the help of our partners at Dallas Fort Worth International Airport, we were able to test, refine, and improve it.”
The guide we created gives airports the insights they need to prepare for how they will respond if GPS is disrupted.
FFRDC
Center for Advanced Aviation System Development
Scoping the Zone of Impact
A GPS disruption event, McCourt explains, doesn’t just affect pilots and air traffic controllers. Its impact can be much broader, possibly disabling multiple airport systems, such as radio systems, physical access controls, information display systems in the terminal, baggage handling, and even airfield lighting.
As a result, one of the MITRE team’s key focuses was to train stakeholders on conducting a comprehensive inventory of the various GPS uses at an airport and how they could be affected if GPS is degraded or becomes unavailable.
“Essentially, we sought to answer the question: What happens to your airport from a safety, security, compliance, and efficiency perspective?” McCourt says. “To do that, you have to look at interdependencies. For instance, even if pilots can use other mechanisms for navigation, if you can’t get passengers through security, it won’t be long before the whole system is disrupted.”
Charting an Effective Response
Armed with the knowledge of potential impacts, the team worked to help Dallas develop its emergency response policies and procedures.
“For every area where there was reliance on GPS, we helped them draft business continuity plans,” McCourt says. “Since Dallas is a major hub airport, we knew those plans would be useful for other large airports, but we wanted our CONOPS to be a resource for smaller airports as well.”
That took the team to Tampa, Florida, to further refine the CONOPS, giving it broader applicability.
“Tampa is not only home to Tampa International Airport, but also to MacDill Air Force Base, the Port of Tampa, the Hillsborough County Aviation Authority, and several airports that support general aviation traffic,” McCourt says. That gave the MITRE team a window into a more complex environment that could be affected by a GPS disruption.
“The ecosystem extends beyond the fence line of an airport,” McCourt says. “If GPS is disrupted, it’s probably disrupted for many in the area, or perhaps even a whole state. In our CONOPS, we emphasize the importance of making airports part of formal state and federal communication and response plans.”
Any one entity in the ecosystem experiencing a GPS degradation or a disruption event shares that information with other organizations that could be affected. “In that way, every entity serves as a ‘sensor’ and can support the development of a common operating picture for everyone,” McCourt says.
Preparing All Airports with a Best Practices Guide
The team’s work is now being compiled into a best practices guide expected to be made available as a free resource on the FAA’s website later this year.
“We never know when a GPS disruption is coming,” McCourt says. “This guide gives any airport—large or small—the insights it needs to start preparing for how it will respond. We want to see airports move from an ad hoc approach to one that is formal, harmonized, and habituated for all parties." The guide outlines how they need to go about that. It's applicable to spaceports as well.
“MITRE was uniquely positioned to develop this resource,” adds Rick Niles, who leads MITRE’s GPS resiliency efforts. He cites our deep bench of GPS expertise, in-depth knowledge of aviation operations, and long-standing relationships with both the FAA and the aviation industry as key strengths. “As the operator of FFRDCs, we work in service of the public good. This is a great example of how we can leverage our engineering expertise, vertical technical knowledge, and relationships to find a solution that helps improve the safety and security of GPS for all concerned.”
Contributing to a Larger Initiative
The GPS disruption CONOPS is just one project in a multipronged MITRE initiative to enhance GPS resiliency.
Most GPS interference is unintentional, often stemming from poorly tuned equipment inadvertently broadcasting in the GPS frequency or from natural sources, such as solar flares. Intentional signal jamming is becoming more frequent. And the even more dangerous spoofing—where nefarious actors transmit an incorrect signal that appears real to the receiver—has also become a reality in some parts of the world, particularly in war zones.
As a result, multiple government agencies are calling for innovative ways to better detect GPS interference and strengthen the nation’s GPS resiliency to these events.
“It’s a complex challenge, and MITRE is taking a multifaceted approach to it,” says Niles. “Our airports CONOPS is just one component of that larger effort.” Other MITRE R&D, conducted on behalf of the FAA, has produced a capability that can detect GPS loss-of-service events and identify alternative ground-based navigation services available in the affected area. MITRE researchers are also working on new technologies, algorithms, and authentication systems to detect and thwart spoofing. Internationally, we’re working to help other nations develop augmentation systems that can enhance the reliability and accessibility of signals from GPS and other global navigation satellite systems.
“We’re also working with Space Force to ensure that the next generation of satellites and ground systems are compatible with our aviation system,” Niles adds. “We’re taking the holistic approach that’s needed to ensure not only the resiliency of the GPS system itself but also all the entities and activities that rely on it.”
MITRE-Operated FFRDCs
As a not-for-profit institution committed to the public interest, MITRE operates six FFRDCs: