This article was provided by NPL, the National Physical Laboratory . In addition, new GPS-based time dissemination methods are being introduced to allow the performance of high accuracy time and frequency equipment to be fully assessed against the national time standard.
Time is global Atomic clocks are time standards for counting the passing seconds.
In addition, there are internationally agreed time scales which set the calendar and the beginning of each new day. NPL uses its atomic clocks to contribute to the determination of UTC, along with approximately 230 other clocks from 65 laboratories world wide. This is a system of 24 satellites orbiting the Earth, each with several synchronised atomic clocks on board. Effectively, it is a highly accurate time-transfer system available to anyone with the technology to use it. At any moment on any point on Earth at least 4 satellites can be seen.