RATHER than just give directions, GPS signals could soon help tell when it is going to rain.
Scientists have begun using GPS signals to monitor air moisture to improve weather forecasting.
The method is being incorporated into the Bureau of Meteorology's weather forecast models following successful tests across Australia, off the back of World Space Week 2019.
A collaboration between RMIT university, Geoscience Australia and the BoM helped harness the growing network of GPS receivers to provide more accurate, real-time weather forecasts.
The system works by measuring the time it takes GPS signals from overhead satellites to reach ground receivers.
Signals can be slightly delayed by moisture in the troposphere, causing what is known as a zenith total delay, with scientists able to measure this delay to assess air moisture.
RMIT adjunct professor and Bureau senior principal research scientist John Le Marshall said it was an exciting new capability for real-time weather measurements and forecasting.
"Atmospheric water vapour is highly variable yet vital to accurate analysis and weather forecasting," he said.
"The development of a GPS-based system to improve moisture analysis and forecasting over Australia is therefore an exciting step towards improved humidity and rainfall forecasting."
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This is not the only application for GPS for meteorologists.
Another completed project used the bending of GPS signals through the atmosphere to determine temperature at various altitudes, while this system measures the delay in the arrival of those signals to determine water vapour levels.
While the technology could be applied almost anywhere, the BoM says it is particularly valuable in a sparsely populated country, such as Australia where there is a lack of ground-based meteorological observation stations.
"Weather forecasting is dependent on accurate atmospheric observations, but the limited stations we can draw measurements from across our vast continent has always been an issue," Prof Le Marshall said.
"With this technology we were able to tap into an Australia-wide network of 256 GPS receiving stations, and that number of stations is set to continue increasing over coming years."
A study of the system has been published in Journal of Southern Hemisphere Earth Systems Science.
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