After forming a workgroup to study the issue of GPS/global navigation satellite system (GNSS) spoofing, flight operations support provider OpsGroup has released its GPS Spoofing Final Report, identifying key issues and work underway to mitigate spoofing problems. More than 950 people—including pilots, air traffic controllers, regulatory authorities, manufacturers, GPS experts, and industry group members—helped with the report.
Spoofing occurs when a GPS/GNSS receiver is tricked into calculating a false position by equipment transmitting from the ground. This can show the aircraft in a different location than its actual position and prompt the navigation system to send the aircraft off the desired course.
According to the OpsGroup report, “The greatest safety concern is the degraded functionality of the ground proximity warning system. The system does not operate correctly after spoofing, even if GPS coverage is restored. The number of false alerts is astounding. There is an increasing normalization of risk. As a result, there was widespread apprehension in the workgroup that the decades-long work to reduce controlled flight into terrain accidents is at great risk of being undone.”
Further, once a GPS/GNSS receiver is spoofed, it could be contaminated with false data, the group warned. “This places doubt on the use of GPS at any point after spoofing, especially RNP [required navigation performance] approaches, and RNP en route use.”
OpsGroup has noted a 500% increase in spoofing this year, now affecting an average of 1,500 flights per day, up from 300 per day in the first half of the year. A major concern is that flight crew aren’t being provided technical information about “GPS involvement in aircraft systems” and they are receiving “conflicting crew guidance and incomplete or insufficient procedures, all leading to misunderstandings and knowledge gaps.”
In a survey that saw nearly 2,000 responses, OpsGroup reported, “The results show that a full 1,400 crewmembers (about 70%) rated their concern relating to GPS spoofing impact on flight safety as very high or extreme [and] 91% of all crewmembers rated their concern as moderate or higher.”
While OpsGroup acknowledged that there are “no quick and easy solutions…The key focus in the short term is on mitigation, crew awareness, guidance, and training. In the longer term, the workgroup identified potential solutions to hardware, avionics, and system components… Consideration must be given to the potential for a deepening of the GPS vulnerability problem. In mid-2024, we are already seeing a major increase in both spoofing and impact to aircraft. Locations could widen further, and impacts could worsen.” The group did note that “the over-reliance on GPS for primary navigation places great importance on preserving a sufficient network of conventional ground-based navaids.”
Some good news from the report: “With few exceptions, GPS spoofing is conducted by state actors as a result of regional conflict. The workgroup found no examples of a direct, targeted attack on a civilian aircraft.”