Global Positioning System (GPS) (GPS)

The United States satellite-based positioning, navigation and timing system.

GPS is one constellation within the wider family of global navigation satellite systems. A receiver estimates position and time from the measured travel times of coded signals transmitted by multiple satellites, and can derive speed and course over the ground from successive measurements or signal changes.

Accuracy and reliability are affected by satellite geometry, antenna position, obstructions, atmospheric effects, multipath, interference and spoofing. A navigator should confirm the chart datum, monitor warnings and integrity information where available, and cross-check GPS-derived information with other sensors and observations.