Researchers from Sandia National Laboratories and Ohio State University are working on developing a backup navigation system to keep airplanes on course when GPS signals are compromised. The team is using non-GPS signals from cell phone towers and communications satellites to calculate a vehicle’s position and velocity. The goal is not to replace GPS but to assist it in situations where GPS signals are degraded or unavailable, which can pose dangers to pilots and passengers. This research was presented at the Institute of Navigation GNSS+ conference in Baltimore and is supported by Sandia’s Laboratory Directed Research and Development program.
Despite GPS being the gold standard for navigation due to its speed, precision, and reliability, there are concerns about overreliance on it without a backup system. GPS has become an essential part of everyday life, from landing planes to mapping crop yields, which raises concerns about the potential societal impact of disruptions to GPS signals. The loss or unreliability of GPS is a growing concern, especially for pilots near conflict areas at risk of losing GPS signals, increasing the potential for accidents. Commercial GPS receivers are vulnerable to threats such as jamming and spoofing, which can mislead users into incorrect locations. This highlights the need for alternative navigation systems.
The team is exploring the concept of using non-GPS signals, known as “signals of opportunity,” for navigation at high altitudes. By analyzing radio frequency waves and utilizing techniques such as the Doppler effect, they aim to develop a system that can guide vehicles like aircraft using atmospheric radio frequency waves. By launching payloads attached to antennas into the sky with weather balloons, they are collecting data on cell tower and satellite signals at high altitudes. Challenges include dead zones due to satellite transmission patterns and the sporadic coverage of satellite signals in rural areas like New Mexico.
Processing the collected data is the next step in the team’s research journey. They aim to develop algorithms for real-time navigation systems by matching signals to their transmitters and calculating position and velocity relative to those sources. While the current process is manual, the goal is to automate this process to enhance efficiency. Preliminary findings indicate that cell tower signals were detected at altitudes of around 82,000 feet, suggesting the potential for using these signals for navigation purposes. Overall, the team remains optimistic about the possibilities for alternative navigation systems.
Sandia National Laboratories, a leading research facility managed by National Technology and Engineering Solutions of Sandia LLC for the U.S. Department of Energy’s National Nuclear Security Administration, is at the forefront of developing backup navigation systems. Their research partnership with Ohio State University is focused on addressing the vulnerabilities and limitations of GPS navigation, especially in critical situations where GPS signals are compromised. By exploring signals of opportunity and alternative navigation methods, the team is working towards enhancing the safety and reliability of air travel in challenging conditions.