Spectracom VelaSync 1225, User Manual

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The NTP throughput statistics data can be utilized to calculate mean values and the
standard deviation.
Example log entries include:
Synchronized to (IP address), stratum=1 : NTP is synchronizing to another
Stratum 1 NTP server.
ntp exiting on signal 15 : This log entry indicates NTP is now indicating to the net-
work that it is a Stratum 15 time server because it is not synchronized to its selec-
ted reference.
Time reset xxxxx s : These entries indicate time corrections (in seconds) applied
to NTP.
No servers reachable : NTP cannot locate any of its configured NTP servers.
Synchronized to PPS(0), stratum=0 : NTP is synchronized using the PPS ref-
erence clock driver (which provides more stable NTP synchronization).
Oscillator Log
Displays log entries related to oscillator disciplining. Provides the calculated frequency
error periodically while synchronizing to a reference.
GPS Qualification Log
If VelaSync is connected to a GNSS antenna and is tracking satellites, this log contains a
running hourly count of the number of GNSS satellites tracked each hour. This history
data can be used to determine if a GNSS reception problem exists and whether this is a
continuous or intermittent reception issue.
GNSS reception may be displayed as cyclic in nature. A cyclic 12 hour pattern of
decreased GNSS reception typically indicates that the GNSS antenna has an obstructed
view of the horizon. The GNSS satellites are in a 12-hour orbit, so if part of the sky is
blocked by large obstructions, at the same time every day (at approximately 12 hour
intervals), the GNSS reception may be reduced or may vanish altogether. If this occurs,
the antenna should be relocated to afford it an unobstructed view of the sky.
Every hour (displayed in the log as UTC time), VelaSync counts the total number of satel-
lites that were tracked during that hour. The GNSS qualification log shows the number
of satellites that were tracked followed by the number of seconds that the particular
number of satellites were tracked during the hour (3600 seconds indicates a full hour).
The number to the left of the “=” sign indicates the number of satellites tracked and the
number to the right of the “=” sign indicates the number of seconds (out of a total of
3600 seconds in an hour) that the unit was tracking that number of satellites. For
example, “0=3600” indicates the unit was tracking 0 satellites for the entire hour, while
“0=2700 1=900” indicates the unit was tracking one satellite for 900 seconds, but for
the remaining portion of the hour it was tracking zero satellites.
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VelaSync User's Manual Rev. 3
4.7 Quality Management