Novatel Software Version 4.45 OM-20000026 Rev 1 用户手册
3
Special Data Input Commands
MiLLennium Command Descriptions Manual
21
$TM1A/B
Receiver Time of 1PPS
The $
TM1A
and
TM1B
data messages can be used to time-synchronize multiple receivers which are all referencing
the same external oscillator. First, ensure that
SETTIMESYNC
is enabled. Next, the primary unit must be sending
its 1PPS signal to the
MARKIN
input of the secondary unit. Third, the two units must be communicating via a COM
port. In this configuration, the user can send the $
TM1A
log from a primary to a secondary unit, in a manner similar
to that for $
ALMA
or $
UTCA
. The secondary unit is then able to compare the time information contained in the log
with that of the 1PPS signal, and set its clock even though it may not be tracking any satellites.
The ASCII $
TM1A
data message is generated from a
TM1A
log, and the binary
TM1B
data message is generated from
a
TM1B
log. For descriptions of these data messages, please see the description of the
logs in Chapter 4
and Appendix D. An example of a $
TM1A
data message is as follows:
$TM1A,794,414634.999999966,-0.000000078,0.000000021,-.999999998,0*57[CR][LF]
The $
TM1A
/
B
message refers to the 1PPS pulse which has just occurred. In other words TM1A comes after a 1PPS
pulse. The length of the pulse for the 24 channel L1/L2 MiLLennium GPSCard is a normally high, active low pulse
(1 millisecond), where falling edge is reference.
(1 millisecond), where falling edge is reference.