Final answer:
GPS devices calculate a user's position by receiving time-stamped signals from satellites, with consideration for the speed of light and relativistic effects to ensure accuracy. The technology is based on a grid system of latitude and longitude, a concept utilized for navigation and map-making since ancient times, now modernized for use in today's mobile devices.
Step-by-step explanation:
The Global Positioning System (GPS) devices identify a user's exact location by receiving signals from an array of satellites equipped with precise atomic clocks. These satellites orbit the Earth and at least four can be accessed from any location on the planet. The GPS receiver calculates the user's position by determining the time it takes for the signals from the satellites overhead to reach it. Light travels 50 feet in 50 billionths of a second, so the synchronization of these clocks is crucial to maintaining the accuracy of GPS determinations. This precision is crucial because errors in time measurements could lead to inaccuracies in determining the location.
Furthermore, GPS technology also takes into account relativistic effects to maintain pinpoint accuracy. Due to special relativity, time on the satellites, which have a different velocity relative to an observer on Earth, moves slower. According to general relativity, the weaker gravitational force higher up where satellites orbit means that time actually moves faster on the satellites than on Earth. If these effects were not corrected, GPS systems would lose their accuracy swiftly.
Today, GPS technology is incorporated into various mobile devices like smartphones and has revolutionized navigation and map-making, relying on grid geographic coordinate systems based on lines of latitude and longitude for expressing absolute location. These systems have origins dating back thousands of years and have been modernized to function effectively with contemporary technology.