lidar_packets versus cloud_node/points timestamps

eldorado

Hello,

I'm trying to figure out the difference between the timestamps in cloud_node/points and os1_node/lidar_packets, aka UDP packet.

When plotting delta_t [= UDP - cloud_node] over UDP time, I would expect delta_t to have a constant value, i.e., both the original UDP time and converted time should increase at the same rate. However, I'm seeing a uniformly increasing step function for delta_t, i.e., UDP time outpaces cloud_node time in a step-wise manner.

Can someone explain what's going on?

I assume this holds true regardless of the hardware timing mechanism, e.g., OSC vs PTP vs GPS. Is that true?

Thanks!

SlavaPavlov

Hello @eldorado,

The difference between the two is that cloud_node/points should have the timestamp associated with each individual point (when it was fired), whilst os1_node/lidar_packets should have the timestamp of the UDP packet itself as well as the individual beam timestamps (when it was fired) within the payload of the packet.

I hope it helps!

Best regards,
Slava Pavlov