Section 3: Operation
Page 3-16
NetClock/GTP Instruction Manual
3.3.3 Format
2
This format provides a time data stream with millisecond resolution. The Format
2 data stream consists of indicators for time sync status, time quality, leap
second and Daylight Saving Time. Time data reflects UTC time and is in the
24-hour format. Format 2 data structure is shown below:
CR LF IQYY ^ DDD ^ HH:MM:SS.
SSS
^ LD
where:
CR =
Carriage Return
LF =
Line Feed
I =
Time Sync Status (space, ?, *)
Q =
Quality Indicator (space, A, B, C, D)
YY =
Year without century (99, 00, 01 etc.)
^ =
space separator
DDD =
Day of Year (001 - 366)
HH =
Hours (00-23 UTC time)
: =
Colon separator
MM =
Minutes (00-59)
SS =
Seconds (00-60)
. =
Decimal Separator
SSS
=
Milliseconds (000-999)
L =
Leap Second Indicator (space, L)
D =
Daylight Saving Time Indicator (S,I,D,O)
The leading edge of the first character (CR) marks the on-time point of the data
stream.
The time sync status character I is defined as described below:
(Space) =
Whenever the front panel Time Sync lamp is green.
? =
When the receiver is unable to track any satellites and the Time
Sync lamp is red.
* =
When the receiver time is derived from the battery backed clock
or set manually through the Serial Setup Interface.
The quality indicator Q provides an inaccuracy estimate of the output data
stream. When the receiver is unable to track any GPS satellites, a timer is
started. Table 3-4 lists the quality indicators and the corresponding error
estimates based upon the GPS receiver 1 PPS stability and the time elapsed
tracking no satellites. The Tracking Zero Satellites timer and the quality indicator
reset when the receiver reacquires a satellite.
