Symmetricom XLi IEEE 1588 - Manual (Page 120)

112 XLi IEEE 1588 Clock
997-01510-03, Rev. C, 12/12/2006
S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S
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GPS Antenna (Ok or Open)
The GPS antenna is powered by a 12-volt current from the ANTENNA connector on the rear of the XLi.
If this circuit is complete (e.g., connected to an antenna) GPS Antenna status is OK. If the circuit is
incomplete (e.g., no antenna, a cable break, or a splitter) the GPS Antenna status is Open. If circuit
detects a short, the receiver opens a relay to disconnect power from the circuit, and the GPS Antenna
status is Open.
GPS Time Reference (Primary, Secondary, or Standby)
Configure the GPS receiver as a Primary or Secondary time reference. This setting is used by F74 –
Clock Source Control to control switching between reference sources. Selecting Standby makes the
receiver unavailable as a reference source.
If one time reference is configured as Primary or Secondary, and another time reference is assigned the
same priority, the first time reference is reset to Standby. For example, with GPS receiver 1 configured
as Secondary, when an operator configures GPS receiver 2 as Secondary and saves changes, GPS
receiver 1 is reset to Standby.
The XLi front panel status display identifies the reference source and its priority (e.g. “ GPS PRI ”).
GPS Acquisition State
If the user has determined that the receiver will remain in a static location and sets the GPS operation
mode to Time Mode (
See “F53 – GPS Operation Mode” on page 58. ), the C/A Receiver has the
following acquisition states:
• Survey Position: The receiver is establishing an initial position following a reset. If the receiver
had “current” satellites prior to being reset, it can establish the position in a matter of seconds;
otherwise establishing the position takes a few minutes.
• Start TRAIM: (for Time Receiver Autonomous Integrity Monitoring) The receiver is in Position
Hold and is monitoring the integrity of the time solution using redundant satellite measurements
in order to eliminate unreliable signal information.
• Stop TRAIM: The receiver is ending TRAIM monitoring.
• Start Site Survey: The receiver is checking for changes in its saved static position (occurs after
boot).
• Stop Site Survey: The receiver is ending site survey.
• Position Hold: The receiver has determined its most accurate position, and is using this static
position to calculate its most accurate time solution.
• Dynamic Mode: The user has determined that the position of the system could change and has
set F53 GPS operation mode to Dynamic Mode (see “F53 – GPS Operation Mode” on page 58 ).
The system is resolving its position so that it can compensate for position changes.
Command Line
To obtain the status of the GPS Receiver, enter:
F119<S>B<N><SEP>S<CR>