MissionPlanner Logfile "TimeUS" vs. "GMS"

[Markus Fehr]

Hi,

I've integrated the Piksi with Pixhawk on my Copter. Now I have a question to the logfile I get from the Mission Planner.
The Piksi GPS is logged under "GPS2" and there I have two different time stamps (I think, they are both time stamps).
What is the "TimeUS" exactly, what does it count? And what is GMS, it's kind of a time too, I think? What does the abbreviation GMS mean?

This is logged under "GPS2":
GPS2, TimeUS,Status,GMS,GWk,NSats,HDop,Lat,Lng,RAlt,Alt,Spd,GCrs,VZ,U

Thank's for your help.
Markus

[Clive Turvey]

I'd presume it's milliseconds into the GPS Week (GWk), ie GPS Milli Second (GMS)

GPS is linear time, to get to UTC you have to account for leap seconds thrown into the mix.

[Markus Fehr]

Hi Clive

Thanks, I've just tested it and i get the correct time from my flight. Sounds reasonable GMS = GPS Milli Second :-)

Do you also know what "TimeUS" is?
for example:
in my 1 flight i made there are values like: 1683952096
and in the 2 flight: 430879143

[dzo...@swift-nav.com]

Markus,

I think (but I'm not sure) that TimeUS represents the number of Microseconds on the Pixhawk processor since it turned on.  I am certain that the units of this time are Microseconds, and the 'U' character is intended to represent the greek character for "micro" of SI units.

Best,

Dennis

[Michael Oborne]

Dennis is correct,

message layout

https://github.com/diydrones/ardupilot/blob/3fcda53d114131e0287d1ac146720b394fdbd620/libraries/DataFlash/LogStructure.h#L660

message inputs

https://github.com/diydrones/ardupilot/blob/3fcda53d114131e0287d1ac146720b394fdbd620/libraries/DataFlash/LogFile.cpp#L730

Michael