March 15, 2023, 4:55 pm | Read time: 3 minutes
Everyone knows GPS, and most likely, most people use it in their cars or via smartphones. But what does the term actually stand for, and how does the technology work?
GPS stands for “Global Positioning System.” It is a navigation system with 24 satellites orbiting the Earth in six different orbits at an altitude of 20,000 kilometers. With the help of these satellites, the position of an object or person on Earth can be determined relatively accurately.
The determined position is also synchronized with speed and time information via GPS. This allows GPS to determine where and when an object or person is moving and how fast. The technology is now used in every modern smartphone and forms the basis for popular services such as Google Maps.
Trilateration–How GPS Calculates Position
In addition to the satellites, GPS also includes ground control stations to monitor and control the satellites. To use GPS, you need a GPS receiver, which is now found in every smartphone as well as in smartwatches or navigation devices.
The GPS receiver reads the microwave signals sent by the satellites and then calculates its own position. The technology behind this is called trilateration. The signal from a satellite creates a sphere, the radius of which is measured by the receiver. The receiver repeats this with a total of three satellite signals. This gives it two intersection points, from which it selects the one closest to Earth–its own location.
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GPS Determines Speed
If the GPS receiver is in motion, the distance to the satellites changes, and the new position is calculated. Based on the new position and the time, the receiver determines the speed at which it is currently moving.
For position calculation, however, the GPS receiver must receive signals from at least four satellites. Three are used for trilateration, and the fourth is used to check whether the position calculation is correct.
Through position determination using GPS, it is possible to create very precise maps and perform time measurements. Additionally, a route to a predetermined destination can be determined–the basis for any car navigation system. Ultimately, the “Global Positioning System” can also be used to track or monitor objects and people.
Developed by the U.S. Military
GPS originates from the U.S. military, which initially used the system’s location functions for submarine navigation. In 1983, the U.S. military made its technology publicly available but retained full control over all GPS data. It wasn’t until this control was relinquished in 2000 that GPS usage boomed.
Even though GPS has been continuously improved over the years and more accurate position calculations are possible than before, various navigation systems have been developed in the past. For example, the EU developed the Galileo satellite system. China also has its own navigation satellite system called Beidou.