Atomic clocks used to generate precise time are at the heart of the Global Positioning System. They are used in all the satellites and at all the ground sites that monitor the operations of the satellites. A broad overview of the topic of Precise time and Time Interval (PTTI) is available in PDF format.
Precise Time and Time Interval 500 K pdf
The following three web pages describe the accuracy you can get from GPS in different modes.
GPS Introduction as a web page.
(GPS Overview
also available as a 160 KByte pdf. )
GPS Accuracy Levels
GPS Accuracy Factors
Differential GPS
GPS must time tag its data very accurately. This is a complicated
subject for many reason, not the least of which is the irregular
length of the day. Different time systems, effects and how GPS deals
with them are described in the following.
Time Systems and Dates - GPS Time
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Last Modified/Reviewed:
10 March 2003
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| Material contained herein is made available for the purpose of peer review and discussion and does not necessarily reflect the views of the Department of the Navy or the Department of Defense. |
James Clynch