GPS under threat from cosmic radiation

A panel of scientists has warned that current GPS systems are too susceptible to solar radio bursts.

The findings were announced today at the first Space Weather Enterprise Forum, an assembly of academic, government and private sector scientists focused on examining the Earth's increasing vulnerability to space weather impacts. 

The scientists warned of our increasing reliance on GPS and other technologies using radio waves for navigation, surveying, mining, exploration and even timing of financial transactions, and the expected problems from increases in solar activity.

A major solar flare in December last year created an unprecedented solar radio burst causing large numbers of receivers to stop tracking the GPS signal.

Using specially designed receivers built at Cornell University as "sensitive space weather monitors", Cornell scientists were able to make the first quantitative measurements of the effect of earlier solar radio bursts on GPS receivers. 

"In December, we found that the effect on GPS receivers was more profound and widespread than we had expected," said Paul Kintner, professor of electrical and computer engineering at Cornell.

"Now we are concerned that more severe consequences will occur during the next solar maximum."

Solar activity rises and falls in 11-year cycles. The next peak is expected in 2011, which means that increasing levels of activity could produce more radio bursts.

"This solar radio burst occurred during the solar minimum, yet produced as much as 10 times more radio noise than the previous record," said Dale Gary, chairman and professor of the physics department at New Jersey Institute of Technology. 

"Measurements with our solar radio-telescope confirmed that, at its peak, the burst produced 20,000 times more radio emission than the entire rest of the Sun. This was enough to swamp GPS receivers over the entire sunlit side of Earth."

Worryingly, the December event was the first time that a solar radio burst was detected on the civil Wide Area Augmentation System (WAAS), which uses GPS to assist in avionic navigation.

"Our findings indicate that the effects of this solar burst were less intense on WAAS than on other operational systems, mainly due to the robust system design," said Patricia Doherty, co-director and senior scientist at the Institute for Scientific Research at Boston College. 

"But it is important for us to consider the potential impact of future, more powerful, solar radio bursts during periods of high solar activity."

Anthea Coster, a researcher at the MIT Haystack Observatory, pointed out that there are three key points to remember about solar radio bursts. 

"First, society cannot become overly reliant on technology without an awareness and understanding of the effects of future space weather disruptions, " she said.

"Second, the 6 December event dramatically shows that the effect of solar radio bursts is global and instantaneous.

"Third, the size and timing of this burst were completely unexpected and the largest ever detected. We do not know how often we can expect solar radio bursts of this size or even larger."