Symmetricom Z3801A, User Manual

Page: 51 / 98

Chapter 3 Using the Receiver Status Screen
Using and Reading the Receiver Status Screen
User Guide 3-7
Figure 3-3. Receiver Status Screen Displaying Progress Towards
Steady-State Operation
In the SYNCHRONIZATION area, the >> marker is pointed at the
Locked to GPS line, indicating that the Receiver is locked to GPS and
stabilizing the frequency of its oscillator. This means that the Receiver
has phase-locked its oscillator to the 1 PPS reference signal provided
by GPS, but it is not at its final, or most stable, state. The Receiver is
locked and the front-panel
GPS Lock
LED is illuminated.
For users without the command interface (PC/Terminal emulator
connected to the Receiver), the illuminated
GPS Lock
LED is probably
the first indication that after powerup that the Receiver is moving
towards a stable state.
With the command interface and status screen, you can get more detailed
information. For example, you can read the reference outputs quality
indicators in the Reference Outputs area of the status screen. These are
the Time Figure of Merit (TFOM) and Frequency Figure of Merit (FFOM)
indicators. As shown in Figure 3-3, the TFOM is 4 and the FFOM is 1.
These values will eventually decrease towards the ultimate values that
represent steady-state performance. Refer to the subsection titled
“Reference Outputs,” on page 3-13 in this chapter for more information
about TFOM and FFOM.
Also indicated is a prediction of the accuracy of the Receiver should it
go into holdover operation.
SYNCHRONIZATION
Receiver Status
---------------------------- ----------------------------
[ Outputs Valid/Reduced Accuracy ] ............................
...............................................
......................................................
ACQUISITION
ELEV MASK
Not Tracking: 1
Locked to GPS: stabilizing frequency
UTC
ANT DLY
MODE
AVG LAT
AVG LON
AVG HGT
HEALTH MONITOR
PRN
Recovery
Holdover
Power-up
SmartClock Mode
Satellite Status
Tracking: 6
Self Test: OK Int Pwr: OK Oven Pwr: OK OCXO: OK EFC: OK GPS Rcv: OK
[ OK ]
Time
GPS 1PPS Synchronized to UTC
Position
Reference Outputs
PRN El Az
2
7
19
22
26
SS
82
71
61
84
54
El
70
35
40
71
19 16 13 258
10 deg
4 1
1.000 us
+20 ns relative to GPS
[GPS 1PPS Valid]
18:47:07 31 Jan 1996
0 ns
Survey: 5.4% complete
N
W
37:19:34.937
121:59:50.457
+67.94 m (MSL)
>>
Az
301
186
102
60
317
TFOM FFOM
HOLD THR
1PPS TI
Predict 432.0 us/initial 24 hrs
Holdrover Uncertainty
31 52 16 41