between elements 50 and 78. The FAA IRIG B code uses five of the
Control Function elements to encode satellite lock status and time
error flags. For a description of the status and error flag imple-
mentation, refer to the table and the paragraphs below.
Element 53 (530 ms) is the time sync status bit. Element 53 is a Bin-
ary 1 when the receiver locked to GPS, and a Binary 0 when the
receiver is not locked to GPS.
Element 55 (550 ms) is the ±1.0 millisecond error flag. Element 55 is
set to Binary 1 when the expected time error is within +/- 1.0 mil-
lisecond, and a Binary 0 during all other conditions of operation.
Element 56 (560 ms) is the ±5.0 millisecond error flag. Element 56 is
set to Binary 1 when the expected time error is within +/- 5.0 mil-
liseconds. and a Binary 0 during all other conditions of operation.
Element 57 (570 ms) is the ±50 millisecond error flag. Element 57 is
set to Binary 1 when the expected time error is within +/- 50 mil-
liseconds, and a Binary 0 during all other conditions of operation.
Element 58 (580 ms) is the ±500 millisecond error flag. Element 58 is
set to Binary 1 when the expected time error is within ±500 mil-
liseconds, and a Binary 0 during all other conditions of operation.
Table 5-33: FAA Time Error Indicators
Time Since Loss
of Lock
Status/Error
Lock Indic-
ator
±1ms ±5ms ±50ms ±500ms
N/A Locked Error <
2μs
1 0 0 0 0
< 00:16:40 Unlocked Error <
1ms
0 1 0 0 0
00:16:41 to
01:23:39
Unlocked Error <
5ms
0 0 1 0 0
01:23:40 to
13:53:19
Unlocked Error <
50 ms
0 0 0 1 0
13:53:20 to 5 days
18:53:19
Unlocked Error <
500 ms
0 0 0 0 1
>5 days 18:53:20 Unlocked Error
Unknown
0 0 0 0 0
N/A Power On 0 0 0 0 0
598 SecureSync 2400 User Manual
APPENDIX
To Next Page
Loading...
