A system with three parts
The Global Positioning System brings together satellites, ground facilities, and receivers. Satellites send signals, ground operations support the system, and a receiver uses signals from multiple satellites to calculate its position. A phone’s map is an application built around location information; the satellite system itself is not sending a street map to every individual screen.
Why several satellites matter
A receiver compares information from multiple signals to work out where it is. NASA’s introductory explanation describes using four or more satellites to establish position. The calculation depends on understanding signal travel and time. This connection between navigation and timing helps explain why positioning systems matter beyond simply showing a traveler where to turn on a road.
Accuracy is a separate question
Readers should distinguish the existence of a position estimate from the accuracy required for a particular task. Equipment, surroundings, and the use case all matter. A general explanation cannot guarantee that any specific device will work in every setting. When reading military technology coverage, ask whether a story is about navigation, precise timing, or a broader use of satellite information. Avoid carrying an everyday phone experience directly into assumptions about specialized equipment. The underlying principle is accessible, but the implementation can vary greatly. Understanding that distinction makes it easier to evaluate claims while appreciating a remarkable engineering achievement: distant signals can help people on Earth connect a place with a precise measurement of time.