3.2.2 Timescale Offset(s)
Timescale offsets account for fixed differences between timescales, in seconds.
Timescale offsets may change because of leap seconds, see "Leap Seconds"
below.
3.2.2.1 Configuring a Timescale Offset
To configure a timescale offset to the System Time:
1. Navigate to MANAGEMENT > OTHER: Time Management.
2. In the Offsets panel on the left, click the GEAR icon in the top-right corner.
3. The Edit GPS Offset window will display. Enter the desired GPS Offset in
seconds, and click Submit.
Note: Since the GPS Offset and the TAI Offset have a fixed rela-
tionship, only the GPS Offset can be set. If only the TAI offset
is known, subtract 19 from it, in order to obtain the GPS offset.
Note that the data stream of GPS and several other external references includes
information about a pending Leap Second, and as such automatically corrects for
a Leap Second. Nevertheless, it is advisable to perform some testing in advance
to ensure all system components will adjust flawlessly. For more information, see
"Leap Seconds" below.
3.2.3 Leap Seconds
3.2.3.1 Reasons for a Leap Second Correction
A Leap Second is an intercalary
1
one-second adjustment that keeps broadcast
standards for time of day close to mean solar time. Leap Seconds are required to
synchronize time standards with civil calendars, thus keeping UTC time in sync
with the earth’s rotation.
Leap seconds can be introduced in UTC at the end of the months of December or
June. The INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS
SERVICE (IERS) publishes a bulletin every six months, either to announce a time
step in UTC, or to confirm that there will be no time step at the next possible
1
Intercalary: (of a day or a month) inserted in the calendar to harmonize it with the solar year, e.g., February
29 in leap years.
3.2 System Time
CHAPTER 3 • VersaSync User Manual Rev. 12
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