Microsemi SyncServer S200, User Manual

Page: 50 / 190

Web Interface
REFERENCES Tab
Select a topic from below to learn more about the REFERENCES features of the Web Inter-
face:
REFERENCES-GPS
Note: This option is not available for the S250i model
GPS Position and Operating Mode
This page can be used to view or set the GPS receiver's Position and Mode, as well as the
GPS Antenna Cable Delay.
Status: Indicates whether the GPS receiver is a valid reference (locked) or not (unlocked).
Current Position : The GPS antenna position in Latitude and Longitude by degrees, minutes,
and seconds, and the cardinal points of the compass followed by the altitude in Meters.
These values can be permanently set when the
GPS Mode is set to Position Hold .
Mode :
n
Survey : In this mode, the receiver surveys and averages its position before switching to
Position Hold mode. Use this setting for stationary applications, such as server rooms.
This is the default setting.
n
Dynamic : In this mode, the receiver continuously updates its position. Use this setting if
the position of the SyncServer could change occasionally or continuously, such as
vehicles, aircraft, and ships. This setting provides lower timing precision and accuracy
than the Survey and Position Hold modes.
n
Position Hold : In this mode, the receiver calculates the time based on a fixed position that
has been provided by Survey Mode or entered by the user. Use this setting if GPS vis-
ibility is poor and the receiver has difficulty establishing its position using Survey mode
after one day. The accuracy of the user-entered position affects the accuracy of the tim-
ing solution from the GPS reference. Also see
Operating in "Window Mode" (on page
102).
Position Entry : Allows values of latitude, longitude, and altitude to be manually entered. Once
the values have been entered, click the APPLY button.
Antenna Cable Delay :
Use this setting to achieve the highest timing precision and accuracy on the timing outputs
such as IRIG Out or 1PPS Out. This setting has a negligible effect on NTP synchronization
because the scale of the adjustment (nanoseconds) is not significant compared to mil-
lisecond latencies on typical networks.
The Antenna Cable Delay advances the Hardware Clock slightly to cancel out the signal
delay caused by the length of the GPS antenna cable.
To calculate the adjustment, select the signal propagation rate for the appropriate cable type
from the table below and multiply it by the length of the cable.
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