The GPS time is based on atomic clocks and has no correction with respect to proper time variations of the Earth's rotation: the only corrections made on atomic clocks located on satellites are very small adjustments to ensure that they remain perfectly synchronized with atomic clocks installed on the Earth (usually to correct drifts due to relativistic effects). Sometimes the UTC time is also called "Zulu time", simply for the fact that time is briefly referred to as "Z time" in naval-air navigation and the letter Z is articulated as "Zulu" in the NATO phonetic alphabet. This second is called "leap second" and its calculation starts from 1972. It is typically taken off one second every 36 months, although of course this is not a certain and scientific rule. With this change in duration of minutes, you do so in order to keep the delay between the UTC and the "earth time" within 0.9 seconds: when needed (typically on June 30th or December 31st), on the recommendation of the International Earth Rotation and Reference Systems Service (IERS, which deals, among other things, the measure of Earth's rotation), is considered a minute with duration of 59 or 61 seconds. On last June 30th 2015 a minute with 61 seconds has been considered: this variation depends on the time of rotation of the earth around the sun, which, due to fluctuations in its velocity, is not constant.
Simplifying, the UTC time divides time into days, hours, minutes and seconds, but while one day is always of 24 hours and one hour always of 60 minutes, a minute, while almost always consists of 60 seconds, sometimes it can be a period of 59 or 61 seconds. It is similar to Greenwich Mean Time (GMT), but unlike this time, it is not based on the time of rotation of the Earth, but on measurements made by atomic clocks that are most accurate and above all more stable over time. UTC time - Coordinate Universal TimeĬoordinated Universal Time is the time zone "0" from which all other time zones around the world are then calculated. There are many standard definitions of the time, but the main four are: UTC, GPS, LORAN and TAI. Typically this time is maintained by specific atomic clocks and has a satellite distribution. However, operating system delays may degrade the accuracy to some degree.A lot of the current technology to work properly requires a very precise definition of the time.
In most cases, the displayed time is correct to within an uncertainty equal to the network delay. The network delay can be used to estimate the uncertainties in the displayed official time and the clock offset. The network delay is equal to one half the period of time it takes for a roundtrip exchange of messages between your device and NRC's atomic clocks. You can adjust your device's clock manually, or have it set automatically through the use of Network Time Protocol (NTP). thousands of seconds), check that your computer settings for the date, time zone, or daylight saving time are correct. The offset of the clock in your device from NRC official time is also shown ('Your local clock is _ seconds fast / slow'). For more information on Canadian time zones consult Time zones & daylight saving time. If you are outside North America, the display will show UTC (Coordinated Universal Time – the modern implementation of Zulu time or GMT). If you are in North America, the display will usually show time according to your time zone. The time displayed is corrected for measured network delays. Your computer or mobile device receives the official time through a periodic exchange of time-stamped messages between your device and NRC's time source. The time displayed on your screen is derived from Canada's official time source: NRC's atomic clocks. How is the official time displayed on my screen?
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