Global Positioning System (GPS)

The accuracy of timing is very important in operation of GPS because radio waves travel at a very high speed (3x108m/s). A timing error of just 10µs represents a distance measurement error of 3000meters. In this case, a high accuracy clock is use in the satellites which is an atomic clock. In today technology, composite clock are use to define GPS timescale.

• Atomic Clock
• Composite Clock