A GPS receiver is a device that determines its location using signals from satellites in the Global Positioning System (GPS). It calculates its position by triangulating signals from at least four satellites, allowing it to provide accurate information about latitude, longitude, and altitude. These receivers are commonly found in various devices, including smartphones, cars, and handheld navigation tools. They are essential for navigation, mapping, and location-based services, helping users find directions, track movements, and explore new areas efficiently.