Solar Radio Burst Effects on Global Positioning System Receivers

Abstract

This thesis presents a series of studies investigating solar radio burst effects on Global Positioning System (GPS) receivers along with supporting instrumentation and analysis techniques. Solar radio bursts are a space weather phenomenon with its origins at the sun. Although solar radio bursts have been widely studied since the 1960s and have been known to cause notable problems for radio communication systems such as cell phone networks (Lanzerotti et al., 1999) their impact on GPS was underestimated and largely ignored by the community. Recent large solar radio burst events in conjunction with accurate carrier-to-noise measurements from GPS receivers has allowed for the first precise qualitative and quantitative analysis of their impact. To the receiver, a solar radio burst is a wide-band radio interference source that causes an effective decrease in the received carrier-to-noise ratio. The analysis of moderate events on 7 September 2005 allowed for the prediction that larger solar radio bursts would present a significant challenge to GPS availability as soon as the next solar maximum in 2011-2012 (Cerruti et al., 2006). The future came sooner than expected when the record setting solar radio burst of 6 December 2006 caused wide-spread outages of GPS receivers. The event exceeded 1,000,000 SFU, was about ten times larger than any previously reported event, and was all the more surprising since the solar radio bursts occurred near solar minimum. These events had a drastic impact on several critical GPS systems utilized by the scientific community, the Federal Aviation Administration, oil-rig operations, orbiting satellites, and surveying. The size of the December 2006 bursts strongly suggests that the historical record may be inaccurate and raises the possibility for even more intense solar radio bursts during the next solar maximum that will significantly impact the operation of GPS receivers.