Researchers from Google and the University of Colorado Boulder (CU Boulder) have utilised millions of Android phones around the world to generate one of the most detailed maps to date of the uppermost layer of Earth’s atmosphere, the university reports.
Using standard GPS sensors in smartphones, the team were able to collect data on how the ionosphere warped signals coming from satellites, illuminating different phenomena in the atmosphere including plasma bubbles – areas of low concentrations of charged particles that can disrupt satellite communications, navigation and radio systems. Maps were created using aggregated measurements of some Android devices, with privacy protections in place to ensure the data could not be used to identify any contributing individual devices. Their findings, published Wednesday in the journal Nature, might help significantly improve the accuracy of GPS technology worldwide.
“These phones can literally fit in your palm,” Jade Morton, a member of the research team and professor in the Ann and HJ Smead Department of Aerospace Engineering Sciences at the university, told the campus news outlet CU Boulder Today. “But through crowdsourcing, we can use them to change the way we understand the space environment.”
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The ionosphere extends about 50 to 1,500 kilometres above our planet, its outer edge marking the border between the Earth’s atmosphere and space. It’s a volatile area, a soupy mix of charged particles that grows and shrinks depending on the energy it absorbs from the Sun, and those fluctuations can play havoc with GPS technology.
Morton explained to CU Boulder Today that GPS essentially works as a stopwatch, using the time it takes satellite radio waves to reach a device to pinpoint its location. Activity in the ionosphere can warp that simple process, something scientists have tried to account for by mapping this part of the atmosphere with ground-based radar. These radars, however, can only observe about 14 percent of the ionosphere at a given time, which can throw off measurements by up to a few dozen metres – a serious problem for activities that require pinpoint accuracy, like landing aircraft.
The smartphones used in the study, on their own, can observe around 21 percent of the ionosphere. Much of that overlaps with ground radar, but together they could cover 28 percent – doubling the accuracy of GPS devices. “I have spent my lifetime building dedicated instruments to do scientific research,” Morton explained to the university news outlet. “But as technology advances in our society, we see all these sensors at our disposal that have a lot more power than we ever imagined.”
