GPS Can Be Doing More Than You Thought


GPS Can Be Doing More Than You Thought

Below are just five scientific programs that take the navigation system past the map

You may think you are an expert at navigating through city traffic with smartphone in your side. You might even rely on GPS device to locate your way through the back country. However, you'd probably be surprised at all the things that GPS which underlies all of modern navigation--could do.

GPS is made up of constellation of satellites which send signals to Earth's surface. A basic GPS receiver, just like the main one inside your smartphone determines where you might be --to over roughly 1 to 10 meters--by measuring the arrival time of signals from four or more satellites. With fancier (and more expensive) GPS receivers, scientists could pinpoint down their positions to centimeters or maybe millimeters. Utilizing that fine grained info, along with fresh tactics to analyse the signals, researchers are discovering that GPS can inform them a lot more about Earth than they originally thought it could.

Throughout the last decade, faster and much more accurate GPS devices have enabled scientists to show how the earth moves during big earthquakes. GPS has led to improved warning systems for natural disasters like flash floods and volcanic eruptions. And researchers have MacGyvered some GPS receivers into acting as snow detectors, wave gauges and other resources that are unforeseen for measuring Earth.

"People thought I was mad once I started talking about those applications," says Kristine Larson, a geophysicist at the University of Colorado Boulder who has directed a number of the discoveries and wrote about them at the 2019 Annual Review of Earth and Planetary Sciences. "It turned out we could actually do it"

Below are some surprising things scientists've just recently realized they could do together with GPS.


For hundreds of years geoscientists have relied upon seismometers, which quantify how much the ground is shaking, to assess how big and how bad a earthquake is. GPS receivers served a different purpose--to track geologic processes that happen on substantially slower scales, such as the pace at which Earth's great crustal plates grind past each other in the process called plate tectonics. S O GPS might tell scientists the speed in which the alternative sides of the San Andreas Fault are progressing past one another, while seismometers measure the ground vibration when that California error ruptures in a quake.

Most investigators thought that GPS only couldn't measure locations precisely enough, and fast enough, to become useful in assessing cyberspace. But it works out that scientists can squeeze extra advice out of the signals that GPS satellites transmit to Earth.

Those signs arrive at just two components. One might be the exceptional set of ones and zeros, called the code, that all GPS satellite communicates. The second is that a shorter-wavelength"carrier" signal that transmits the code by the satellite. As the carrier signal has a shorter wavelength--a mere 20 centimeters--compared with the longer wavelength of this code, which can be tens of thousands or hundreds of meters, the company signal provides a high-resolution means to pin point a spot on the planet's surface. Scientists, surveyors, the military among many others usually require a very precise GPS location, and all it requires is a much more complicated gps-receiver.

Programmers have also improved the rate of which GPS recipients update their position, meaning they are able to refresh themselves often as 20 times per second or more. Once researchers realized they could take precise measurements therefore quickly, they started using GPS to examine the way the ground moved during an earthquake.

Back in 2003, in another of the very first studies of its kind, Larson and her coworkers used GPS receivers hauled across the western usa to examine how the bottom shifted as seismic waves rippled by the magnitude 7.9 earthquake in Alaska. By 2011, researchers could take GPS data on the magnitude 9.1 earthquake that ravaged Japan and show that the sea-floor had shifted a staggering 60 meters through the quake.

Now, scientists have been looking more widely at how GPS data might help them immediately assess earthquakes. Diego Melgar at this University of Oregon in Eugene and Gavin Hayes of the US Geological Survey in Golden, Colorado, retrospectively studied 1 2 large earthquakes to see if they could tell, within seconds of their quake start , how large it'd get. By adding information from GPS stations close to the quakes' epicenters, the scientists may determine within 10 minutes if the quake would be a harmful size 7 or a completely destructive magnitude 9.

Researchers across the US West Coast have been incorporating GPS in their fledgling earthquake early warning system, which finds ground vibration and informs people in remote cities whether shaking is likely to hit on them so on. And Chile was building out its GPS network in order to have more accurate information fast, that may help predict whether a quake nearby the shore is very likely to cause a tsunami or maybe not.


Beyond earthquakes, the rate of GPS is helping officials respond more quickly to additional natural disasters as they unfold.

Many volcano observatories, for instance, possess GPS receivers arrayed round the hills that they monitor, because when magma begins shifting underground that frequently leads to the surface to shift also. By monitoring how GPS channels around a volcano sink or rise over time, researchers can find a better idea on where molten rock is flowing.

Before a year's enormous eruption of the Kilauea volcano in Hawaii, investigators used GPS to know that regions of the volcano were changing most rapidly. Officials found that advice to help decide what areas to evacuate residents out of.

GPS data may also be useful even after a volcano has faded. Because the signs traveling from satellites to the ground, they have to pass whatever substance that the volcano is ejecting in to the atmosphere. Back in 2013, several research groups studied GPS data from an eruption of this Redoubt volcano in Alaska four years earlier and found that the signs became twisted shortly after the eruption began.

By studying the distortions, the scientists could gauge how much ash had spewed out and how fast it was traveling. In an extreme paper, Larson called it"a brand new method to detect submerged plumes."

Her and her colleagues are working on how exactly to do so using smartphone-variety GPS recipients as opposed to expensive scientific receivers. That may enable volcanologists to set up a relatively inexpensive GPS network and monitor ash plumes while they rise. Volcanic plumes are a large issue for airplanes, which have to fly across the ash rather than risk the particles' clogging up their jet motors.


One of the most unexpected uses of GPS come from the messiest areas of its signal--the parts that bounce off the ground.

A standard GPS receiver, just such as the main one within your smartphonemostly sees signs which are coming directly from GPS satellites overhead. However in addition, it picks up signs which have spilled on the bottom you are walking on and represented upward to your smartphone.

For many years scientists had thought those revealed signals were only noise, a sort of echo that muddied the data and also made it hard to figure out what was going on. But about 15 years past Larson and many others began wondering if they can benefit from the echoes in scientific GPS receivers. She started looking at the frequencies of those signs that represented off the bottom and how those joined with the signals that had arrived directly at the recipient. From that she could deduce qualities of the outside that the echoes had awakened off. "We merely reverse engineered those echoes," says Larson.

This process makes it possible for scientists to know about the ground beneath the GPS receiver--as an example just how much moisture the dirt comprises or just how much rain has accumulated in top. (The snow falls on a lawn, the shorter the distance between the echo and the receiver.) GPS channels could are snow detectors to measure snow thickness, like in mountain areas where snow pack is a significant water resource each year.

The technique also is effective within the Arctic and Antarctica, where there are few weather stations monitoring snowfall year-round. Matt Siegfried, now at the Colorado School of Mines in Golden, and his coworkers analyzed snow accumulation at 2 3 GPS channels in West Antarctica in 2007 to 2017. They found they could instantly measure the changing snow. That's crucial information for researchers wanting to assess how much rain that the Antarctic ice sheet builds each winterand how that compares with what melts away each summer.


GPS might have started off as a way to quantify location on solid earth, but it turns out to be also helpful in monitoring changes in water levels.

In July, John Galetzka, a scientist at the UNAVCO geophysics study organization in Boulder, Colorado, found himself installing GPS stations in Bangladesh, at the junction of the Ganges and Brahmaputra rivers. The aim was to measure whether the river sediments are compacting and the land has been slowly sinking--rendering it more vulnerable to flooding throughout tropical cyclones and sea level rise. "GPS is an wonderful tool to help answer this question and more," Galetzka says.

At a farming community named Sonatala, to the edge of a mangrove woods, Galetzka and his coworkers placed one GPS station on the concrete roof of a primary school. They create another station near, atop a pole hammered to a rice cooker. In the event the floor really is sinking, then then a second GPS station will look as though it's slowly emerging out of the soil. And by measuring the GPS echoes under the stations, the boffins could quantify factors such as how much water can be standing in the rice paddy throughout the rainy season.

GPS receivers may help oceanographers and mariners, by acting as tide gauges. Larson stumbled on this when working with GPS data from Kachemak Bay, Alaska. The station was established to review tectonic deformation, but Larson was curious as the bay also includes some of the biggest tidal variations from the United States. She looked at the GPS signals which were rebounding off the water and up into the receiver, and was able to track tidal fluctuations almost as accurately as a true tide gauge in a nearby harbor.

This could possibly be helpful in parts of the world which don't have long term wave indicators setup --however do have a GPS channel near.


At length, GPS could tease out information about the skies overhead, in a way that scientists hadn't thought possible until only a few short years back. Water vapor, electrically charged particles, and also other elements can delay GPS signals traveling through the air, and which allows researchers to create new discoveries.

One group of scientists uses GPS to review the quantity of water vapor from the atmosphere that's offered to precipitate out like snow or rain. Researchers used these changes to calculate how much water is likely to fall out of the heavens in drenching downpours, allowing forecasters to fine-tune their predictions of flash flooding in regions such as Southern California. Throughout a July 2013 storm, the meteorologists used GPS data to track monsoonal moisture moving onshore there, which was be essential information for devoting a warning 17 minutes before flash flooding hit.

GPS signals are also influenced if they travel through the charged part of the upper atmosphere, called the ionosphere. Boffins purchased GPS data to track changes in the ionosphere as tsunamis race across the sea below. (The force of the tsunami produces changes in the air that ripple all the way up to the ionosphere.) This system could one day complement the traditional method of tsunami warning, which utilizes dotted across the sea to gauge the elevation of this traveling wave.

And scientists've been able to study the outcomes of a total solar panel using GPS. In August 2017, they used GPS stations across the United States to quantify how the number of electrons in the upper atmosphere dropped whilst the moon's shadow moved across the continent, controlling the light that otherwise created electrons.

So GPS is useful for everything from earth shaking beneath your feet to snow falling from the sky. Not bad for something which was simply designed to help you to find your way around town.

This article originally appeared in Knowable Magazine, a separate journalistic endeavor from Annual Reports.