New mystery on Northern Lights


Technology designers were confident they knew why the aurora borealis affected sat-nav systems. New research is sending them back to the drawing board. Andrew Masterson reports.


The aurora borealis
Frank Olsen, Norway

The leading hypothesis used to explain why the aurora borealis and its southern hemisphere counterpart, the aurora australis, play havoc with global positioning systems has been knocked into a cocked hat.

The spectacular auroras are produced when gas particles in the earth’s atmosphere collide with charged particles emitted by the sun. The resulting plasma turbulence has long been assumed to be the reason that the phenomena interfere with Global Navigation Satellite Systems (GNSS). Now, research led by Biagio Forte of the Department of Electronic and Electrical Engineering at the University of Bath in the UK has discovered that the predicted turbulence doesn’t actually exist, meaning that an as yet unknown driver is causing the problem.

To conduct the research Forte’s team collaborated with the European Incoherent Scatter Scientific Association (EISCAT), setting up in northern Norway to observe and analyse the aurora borealis using radar and a GNSS receiver. As the radar team developed visual imagery of the phenomenon, the GNSS team looked at how it interacted with global positioning systems.

The results ruled out plasma turbulence. Instead, the team write in the Journal of Geophysical Research Space Physics, the interference is caused by a “new instability mechanism”, as yet unknown.

Although the Bath researchers work generated far more questions than answers, the study is important because it shifts focus in what is rapidly becoming a critically important field. Global positioning data is already widely used in personal mobile phones, car navigation systems and aircraft, but the imminent roll-out of autonomous vehicles, as well as developments in remote-warfare, mean it will soon be ubiquitous.

"The potential impact of inaccurate GNSS signals could be severe,” said Forte. “Whilst outages in mobile phones may not be life threatening, unreliability in satellite navigations systems in autonomous vehicles or drones delivering payloads could result in serious harm to both humans and the environment.”

See the aurora borealis in ultra-high definition here.

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Andrew Masterson is an author and journalist based in Melbourne, Australia.