Unknown publisher in the tf_monitor output for the turtlebot_gazebo demo.
Run the demo Explore the Gazebo world. Check the tf tree via rqt_tf_tree and obtain the output as below:
You can see that the tf of base_footprint -> base_link is published by the node robot_state_publisher.
But "tf_monitor" shows "unknown_publisher" for base_footprint -> base_link.
RESULTS: for base_footprint to base_link
Chain is: base_link -> base_footprint
Net delay avg = 1114.58: max = 1164.52
Frames:
Frame: base_footprint published by unknown_publisher Average Delay: 0.00476341 Max Delay: 0.02
All Broadcasters:
Node: unknown_publisher 124.051 Hz, Average Delay: 0.00459184 Max Delay: 0.02
Also in the tf tree drawn by "rosrun tf view_frames", there is no tf from base_footprint to base_link.
Also notice that compared with the rqt_tf_tree output, there are many other tfs missing in the view_frames output.
Is this a bug in tf_monitor and view_frames? Or some configurations in the demo are incorrect?