D Logs summary
218 MiLLennium GP SCard Software Version 4.50 Command Descriptions Manual Rev 1
TM1A/B Time of 1PPS
This log provides the time of the GPSCard 1PPS, normally high, active low pulse (1 millisecond), where falling
edge is reference, in GPS week number and seconds into the week. The TM1A/B log follows a 1PPS pulse. I t also
includes the receiver clock offset, the standard deviation of the receiver clock offset and clock model status. This
log will output at a maximum rate of 1 Hz.

TM1A

Structure:
Example:
$TM1A,794,414634.999999966,-0.000000078,0.000000021,-9.999999998,0*57[CR][LF]

TM1B

Format: Message ID = 03 Message byte count = 52
$TM1A week seconds offset offset std
utc offset cm status *xx [CR][LF]
Field # Field type Data Description Example
1$TM1A Log header $TM1A
2week GPS week number 794
3seconds GPS seconds into the week at the epoch coincident with the 1PPS
output strobe (receiver time) 414634.99999996
6
4offset Receiver clock offset, in seconds. A positive offset implies that the
receiver clock is ahead of GPS Time. To derive GPS time, use the
following formula:
GPS time = receiver time - (offset)
-0.000000078
5offset std Standard deviation of receiver c lock offset, in seconds 0.000000021
6utc offset This field repres ents the offset of GPS time from UTC time, computed
using almanac parameters. To reconstruct UTC time, algebraically
subtract this correction from field 3 above (GPS seconds).
UTC time = GPS time + (utc offset)
-9.999999998
7cm status Receiver Clock Model Status where 0 is valid and values from -20 to -1
imply that the model is in the process of stabilization 0
8*xx Checksum *57
9[CR][LF] Sentence terminator [CR][LF]
Field # Data Bytes Format Units Offset
1Sync 3char 0
(header) Checksum 1char 3
Message ID 4integer 4
Message byte count 4integer 8
2Week number 4integer weeks 12
3Seconds of week 8double seco nds 16
4Clock offset 8double seconds 24
5Stddev clock offset 8double se conds 32
6UTC offset 8double secon ds 40
7Clock model status 4integer 48