It is effectively a successor to Greenwich Mean Time (GMT). It is within about 1 second of mean solar time (such as UT1) at 0° longitude (at the IERS Reference Meridian as the currently used prime meridian) and is not adjusted for daylight saving time. The weeks are transmitted with a 10-bit encryption, which means that the number of weeks spent is reset every 1024 weeks (about 19.6 years) and the last reset (and for now the only one) has been on 21st August 1999.Coordinated Universal Time or UTC is the primary time standard by which the world regulates clocks and time. The data received from GPS are based on the instant "0" just mentioned: in substance, the system transmits the number of weeks spent by January 6th, 1980 and the number of seconds since the beginning of the current week. The time "0" which first GPS timing started is midnight on January 6th, 1980 (UTC time): in that year, the GPS time coincided exactly with UTC time, as a result of corrective measures to UTC time, today it differs by 18 (it was 17 until December 31st 2016 and 16 seconds until June 30th 2015), seconds compared to GPS time, which as written above, is not subject to any astronomical adjustment. 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. A lot of the current technology to work properly requires a very precise definition of the time.
0 kommentar(er)
