What primary technology supports GPS systems?

The primary technology that supports GPS systems is radio satellites. Global Positioning System (GPS) relies on a constellation of satellites that transmit signals to GPS receivers on Earth. These satellites are equipped with highly accurate atomic clocks and continually broadcast their location and the time the signal was transmitted. When a GPS receiver picks up signals from multiple satellites, it can determine its precise location using a technique called trilateration, which calculates distances based on the time it takes for signals to travel from the satellites.

Radio waves are the medium through which these signals are transmitted, which confirms the role of satellites utilizing radio technology in GPS functionality. The other options, such as fiber optic cables, microwave signals, and laser beams, do not serve as the foundation for GPS technology in the same manner, as fiber optic cables are typically used for wired communications, while microwave signals and laser beams are employed in different types of communication technologies and applications.