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Why do I see negative average delay in tf_monitor?

asked 2011-03-18 14:51:30 -0500

tfoote gravatar image

It seems to be only when I run simulation.

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answered 2011-03-18 14:51:45 -0500

tfoote gravatar image

Negative average delay comes from the transform being timestamped in the future when sent or by network delays when running in simulation.

In simulation time is sent over the /clock topic and may arrive after transforms sent from a different node with the same time.

A few nodes stamp data in the future, most noteably AMCL. This is valid for AMCL and other similar nodes publishing a small correction transform which is expected to remain approximately static and never have inherent velocity. The value is that AMCL can update at a slow rate but does not prevent transforms through it's correction to be used at a high rate.

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Asked: 2011-03-18 14:51:30 -0500

Seen: 749 times

Last updated: Mar 18 '11