N00b questions about ROS time

[DaveC]

When ROS is passing time stamps around, it looks like it is seconds in floating point. So what are the seconds? Is that the standard UNIX interpretation, ie: seconds-since-the-epoch? When ROS nodes running on different systems are trying to synchronize, do they all use their own wall-clocks to time-stamp the generated sensor readings, etc?

-dave

[lnxfergy]

The time is in UNIX standard seconds-since-the-epoch (january 1, 1970). If you have multiple different computers, you want to make their clocks synchronized (NTP via chrony works well on Ubuntu).

-Fergs

[DaveC]

Thanks, makes sense. I can see where NTP is going to be required to make the time stamps work well.