Although GPS is considered highly reliable, it is not immune to various problems. Scientists have proposed using mobile communications as a backup navigation solution for aircraft in the event of GPS failure. (Image credit: Getty Images/rbkomar)
Researchers are testing an alternative to the Global Positioning System (GPS) that uses cellular signals as a backup source for pilots if their standard onboard equipment stops functioning.
The 31 working GPS satellites orbit the Earth twice every day, sending out precise signals that receivers on the ground can receive and analyze to determine their distance from the satellites. GPS devices rely on data from three satellites to accurately calculate a user's location.
While GPS is highly reliable (the Federal Aviation Administration (FAA) has certified it to be accurate to seven meters 95 percent of the time), it is not immune to problems. GPS signals cannot be relied upon in and around conflict zones, as they can be jammed by malicious actors. Hackers can also “spoof” GPS signals, misleading pilots about their location and direction of travel. GPS systems can also malfunction or fail entirely. If a commercial airliner loses GPS signal, it could endanger everyone on board.
Additionally, GPS systems can function intermittently or stop working altogether. If a commercial airliner loses GPS signal, it could endanger everyone on board.
“The impact of losing GPS could be felt across the country,” said lead study author Jennifer Sanderson, an electrical engineer at Sandia National Laboratories and an expert in navigation algorithms.
The project, led by scientists at Sandia National Laboratories and Ohio State University, aims to develop a robust safety net for onboard navigation systems that uses a floating receiver to detect radio waves from cell towers and communications satellites in relation to an aircraft. That information is then used to provide pilots with navigation data.
Signals that can be used for navigation, even if that is not their primary purpose, are known as “signals of opportunity.” They can use processes such as the Doppler effect, in which waves are compressed or stretched depending on whether they are approaching or moving away from a certain point, to determine position and speed.
Scientists said preliminary results showed the detection of cell tower beacons at altitudes of 82,000 feet.
In this experiment, the researchers attached antennas to weather zones and sent them out
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