GPS time refers to the time standard set by the atomic clocks on satellites of the Global Positioning System (GPS), which is used to determine and distribute precise time and coordinate data globally. Unlike Universal Coordinated Time (UTC), GPS time does not incorporate leap seconds which are periodically added to account for the Earth’s slowing rotation. Instead, GPS time counts in weeks and seconds from its epoch, which is 00:00:00 on January 6, 1980, UTC.

GPS time is calculated by measuring the time it takes for signals to travel from multiple GPS satellites to a GPS receiver. Each GPS satellite transmits data that includes the time the message was transmitted and the satellite’s position at that time. By comparing the time a signal was transmitted to the time it was received, a GPS receiver can calculate how far away the satellite is. With signals from at least four satellites, the receiver can determine its own three-dimensional position and the time deviation from GPS time.

GPS time is critical for the functionality of the GPS system itself, as accurate timing is crucial for triangulating positions. It’s widely used in various applications, including transportation (aviation, maritime, and land navigation), telecommunications (network synchronization), financial services (timestamping transactions), and scientific research (time-stamping data collection). It is also relevant for military operations, where precise timing is essential for coordinating maneuvers and operations.