Gps devices how does it work

By submitting your email, you agree to the Terms of Use and Privacy Policy. We already live in the future. We have handheld devices that use satellites to pinpoint our precise locations almost anywhere on the planet.

But have you ever wondered just how GPS works? The global positioning system was originally created by the United State for military use, but was eventually opened up to civilian use. The satellites are arranged in orbit such that four satellites are visible in the sky from any point on Earth.

GPS satellites are constantly transmitting radio signals towards the Earth. Each transmission includes the location of the GPS satellite and the time the signal was sent. Each satellite has an atomic clock onboard, so the time is very precise. Image Credit: Cliff on Flickr. This process works using the mathematical principle of trilateration. A stranger walks by and tells you you are miles from Minneapolis.

You could be anywhere on the circle with a radius of miles from Minneapolis. Think of it as a Venn diagram of sorts. And sure enough, Denver is miles from Minneapolis, miles from Tuscon, and miles from Boise. By the time you introduce three satellites, for instance, those spheres intersect at only two points—and only one of those points can be on Earth.

GPS receivers use four satellites, however, instead of three to help ensure greater accuracy as well as to determine elevation. The best GPS tracker units have multiple receivers so that it can pick up signals from multiple satellites simultaneously. And because the receivers know that radio waves travel at the speed of light, they can determine how far they are from each satellite based on the atomic clock time signature of when the radio wave was sent and the time it took for that signal to get to the receiver.

Instead, both satellites and receivers run digital patterns of code; the receiver knows how long a signal from the satellite took to reach the receiver by noting the lag in the code. The receiver can simply look at the time signals from the satellites and gauge its own inaccuracies, correcting to that time value.

Credit: NOAA. GPS can be used to keep an eye on dangerous natural hazards, too! Tsunamis GPS can help provide early warning of tsunamis. Credit: mnlamberson. GPS is used to monitor volcanoes. Credit: Earth Uncut Productions Ltd. The aftermath of Earthquakes can be rapidly monitored using GPS. Orbits 'R' Us! Telling a pine from a maple More Less.