18,519
edits
Global Positioning System: Difference between revisions
From ScoutWiki, For Everyone, Everywhere involved with Scouting and Guiding...
m
Robot: Automated text replacement (-\[\[(Leap seconds)\]\] +\1)
m (Robot: Automated text replacement (-\[\[Gregorian calendar\|([\w|\s]*)\]\] +\1)) |
m (Robot: Automated text replacement (-\[\[(Leap seconds)\]\] +\1)) |
||
| Line 159: | Line 159: | ||
=== GPS time and date === | === GPS time and date === | ||
While most clocks are synchronized to [[Coordinated Universal Time]] (UTC), the [[Atomic clock]]s on the satellites are set to '''GPS time.''' The difference is that GPS time is not corrected to match the rotation of the Earth, so it does not contain | While most clocks are synchronized to [[Coordinated Universal Time]] (UTC), the [[Atomic clock]]s on the satellites are set to '''GPS time.''' The difference is that GPS time is not corrected to match the rotation of the Earth, so it does not contain leap seconds or other corrections which are periodically added to UTC. GPS time was set to match [[Coordinated Universal Time]] (UTC) in 1980, but has since diverged. The lack of corrections means that GPS time remains synchronized with the [[International Atomic Time]] (TAI). | ||
The GPS navigation message includes the difference between GPS time and UTC, which as of 2006 is 14 seconds. Receivers subtract this offset from GPS time to calculate UTC and 'local' time. New GPS units may not show the correct UTC time until after receiving the UTC offset message. The GPS-UTC offset field can accommodate 255 leap seconds (eight bits) which, at the current rate of change of the Earth's rotation, is sufficient to last until the year 2330. | The GPS navigation message includes the difference between GPS time and UTC, which as of 2006 is 14 seconds. Receivers subtract this offset from GPS time to calculate UTC and 'local' time. New GPS units may not show the correct UTC time until after receiving the UTC offset message. The GPS-UTC offset field can accommodate 255 leap seconds (eight bits) which, at the current rate of change of the Earth's rotation, is sufficient to last until the year 2330. | ||
