To get local time from a UTC broadcast, both a time zone and daylight saving time correction usually needs to be made. Fortunately, these corrections are made automatically by the radio receivers and software packages that access NIST services after you configure them for your time zone. Once TAI is corrected for leap seconds , it becomes UTC, or the official world time scale. Precise time synchronization has many uses in everyday life. Synchronization between two or more locations is necessary for high speed communication systems, synchronizing television feeds, calculating bank transfers, and transmitting everything from e-mail to sonar signals in a submarine.
Power companies use precise time to regulate power system grids and reduce power losses.
Precise time measurements are also essential for accurate navigation and the support of communications on earth and in space. Scientific organizations such as NASA depend on reliable and consistent time measurement for projects such as interplanetary space travel. Fractional disparities in times between a space probe and tracking stations on Earth can dramatically affect the positions of spacecraft. By synchronizing the satellite clocks within nanoseconds of each other, it makes it possible for a receiver to know its position on earth within a few meters. Other physical quantities, like the volt and meter, also rely on the definition of the second as part of their own definitions.