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MIT-SPARK / Kimera-Multi-Data

A large-scale multi-robot dataset for multi-robot SLAM
MIT License
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Question about time sync #13

Closed minje-KIM closed 1 month ago

minje-KIM commented 6 months ago

Hello! Thanks for sharing wonderful dataset, Kimera-multi dataset! I have some question about dataset.

May I ask how you set the time sync to make the Kimera multi dataset? Did you use GNSS or NTP? I would appreciate it if you could explain it from the perspective of inter and intra!

yunzc commented 6 months ago

Hi, thanks for your interest in our dataset.

We did not have inter-robot time sync (since we were intentionally testing with bad comms between the robots and no GNSS signal). On a single robot, the synchronization is done through NTP with the server being the robot base computer.

minje-KIM commented 6 months ago

Thanks for your answer!

What I'm trying to say is, The inter sync is the time sync between the sensors that made up one robot. and the intra sync is the time sync between robot 1, robot 2 and robot n, from this point of view, the part corresponding to the intra time sync is NTP, Can i see it that way?

LimHyungTae commented 1 month ago

In inter case, I guess there are no external triggers.

In intra case, the messages are synced with the msg time. So, I experienced the timestamp of each rosbag having a different times with each msg.