Drivers beware: satellite navigators are star struck

July 22nd, 2008 - 2:14 pm ICT by IANS  

By Venkata Vemuri
London, July 22 (IANS) The next time the satellite navigator in your car directs you to London Road in Leicester instead of the national capital, blame the aurora borealis - natural coloured light displays in the sky, usually observed at night. A study by the University of Bath’s department of electrical engineering is the first to find that the aurora borealis, which can be seen from most parts of Britain, directly affects the satellite navigator.

A truck driver going from Turkey to Gibraltar Monday ended up at Gibraltar Point near the North Sea in rural England, 1,600 miles (around 2,575 km) away, thanks to his satellite navigator.

Birdwatchers at Gibraltar Point looked on in astonishment as Necdet Bakimci tried to steer his 32-tonne lorry down a narrow lane towards the North Sea. The confusion arose because his device had the Gibraltar Rock listed as British territory and so directed him towards the mainland.

The blunder is one of a series that is prompting calls for drivers to use more common sense and less technology when taking to the roads.

It follows the recent case of four actors from a touring theatre company who had to be rescued from the roof of their pink Mercedes van after their satellite navigator directed them through a flooded ford in Gillingham, Dorset.

Lorries have already caused an estimated 15 million pounds of damage to low railway bridges in just 12 months. The government is considering introducing signs on country roads to prevent lorry drivers from being led down unsuitable routes.

The Telegraph reports that Insurers Direct Line have conducted a poll which showed that one in 50 of the 14 million drivers - nearly half of Britain’s driving population - who now use the device believed it had caused or nearly caused an accident.

A further one in three admitted they had driven down a one-way street because of it, while one in 10 admitted performing sudden manoeuvres or changing direction because they were following its directions.

Direct Line’s Maggie Game warned: “If a satnav gives you an instruction that is likely to endanger other road users, ignore it.”

But why do the satellite navigators fail? Scientists have discovered that the natural light shows of the Northern Lights - or aurora borealis - interfere with the signals from global positioning satellites, which are used by the navigators to pinpoint the locations of vehicles, boats and aircraft.

The intense electrical activity created in the atmosphere by the Northern Lights decreases the accuracy of the system, telling drivers that they are on a road they are not actually on or causing receivers to lose track of their position entirely.

The aurora, which occur at both the North and South Poles, are caused by high-speed particles from the sun hitting the atmosphere and releasing energy as brightly coloured light.

Under normal circumstances, the upper layers of the atmosphere, known as the ionosphere, behave like a smooth plate of glass, allowing the signals from the satellites to pass straight through. But during the aurora, the ionosphere becomes “lumpy”, which disrupts the signals.

Experts describe the effect as like looking into a fish tank. Because of the way light bends when it enters water, an object in the tank appears to be in a spot offset from its actual position.

Cathryn Mitchell, who led the research, said satnav errors were likely to become more frequent over the next four years due to increasing aurora activity.

“Anywhere that the aurora is visible, it will cause disruption,” she said. “Although most people in the UK can’t see the aurora when it is happening, because of cloud or ambient light, it can still affect the GPS signal. We have just passed a minimum in activity but we are due to hit a maximum in 2012, which is when we would expect to see most disruption.

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