GPS Interference

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Solar Storms Might Impact GPS

August 16, 2011

On August 9, 2011, a huge explosion on the surface of the sun not only sent a wave of radiation sweeping outward into space. It was the largest flare since 2006 and heralded the coming of an active solar storm season. That will likely spell occasional trouble for GPS approaches and satellite-based communications over the next decade – or perhaps longer.

Although last week's flare wasn’t aimed at the Earth, Joes Kunches, a scientist at the National Oceanic and Atmospheric Administration (NOAA) told the Los Angeles Times, "We are now seeing more eruptions this year and we will see even more the year after that. They are going to get bigger and they are going to get more frequent."

Those eruptions will likely cause temporary disruptions in signals from Global Positioning Satellites, making GPS approaches sometimes unreliable.

Kunches predicted the solar cycle just now beginning will likely be "in the moderate to strong level," and will likely peak in 2013. Before the decade is out, NOAA predicts four "extreme" solar storms could not only disrupt GPS navigation, but lead to power outages and communications disruptions.

Solar radio bursts drown out GPS signals with so much background noise that Earth-based receivers have difficulty picking them up. Wide-Area Augmentation Systems (WAAS) receivers are unable to fully lock onto GPS satellite signals. FAA officials pointed out, however, that only vertical WAAS guidance is lost during solar bursts, while lateral guidance is unaffected.

The FAA, with help from the Institute for Scientific Research (ISR), continues to study the effects of solar storms on GPS and WAAS systems. ISR points out that so far, even during some of worst solar storms, WAAS disruption has generally been minimal, although maintaining Approaches with Vertical Guidance (APV) has been a challenge.