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Your GPS May Not Be Accurate!

Signals from GPS satellites must pass through the ionosphere to reach the Earth. While the ionosphere has a significant impact on communication at lower frequencies—it’s responsible for the “skip” that allows long distance shortwave communications—the impact of the ionosphere on GPS signals is now receiving attention.

The American Geophysical Union (AGU) highlighted some of the research reports in a news release, Interfering with the Global Positioning System, earlier this week. This research may lead to regional predictions of reduced GPS reliability and accuracy. Researchers have observed Earth’s aurora disrupting GPS signals. Researchers are also using the GPS signals as a tool in research on the electrical-current structures of the ionosphere.

The AGU articles focus on the impact of the ionosphere on the use of GPS for navigation. GPS is also used as a stable reference for synchronizing communications systems. Fortunately, engineers designing these systems allowed for these disruptions. Short-term disruption of GPS signals should not have a significant impact on systems using “disciplined clocks” that average the GPS reference over a long period of time.

More information is available in the AGU online Space Weather Journal.

Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.