Getting the odom, rather than Pose

[rakshith95]

Hello @thien94 , Thank you for this wrapper. How can I get the mono_inertial_node to publish nav_msgs:Odometry information, which includes the twist information in addition to the Pose information?

[thien94]

Hi @rakshith95 , thank you for the question.

As far as I know, only the pose data are provided by ORB-SLAM3 as it is. After looking into the code, I have a few ideas regarding how to obtain the linear velocities. However, how to obtain the angular velocities is a mystery to me. Furthermore, the covariance or uncertainty is not computed by ORB-SLAM3 for either pose or velocity. Hence, creating a proper nav_msgs:Odometry message is unlikely to be possible unless you figure out the above or accept that the message is incomplete.

Nonetheless, to obtain the velocity my suggestion is:

• Figure out which variable contains the latest velocity and in which frame (global or body) is it defined. Possible candidates are mVw or mVelocity, with the former seems more likely.
• Modify Tracking.cc and System.cc to allow access the the aforementioned variables.
• Modify the ROS wrapper (either this package or the provided example) to obtain the velocities, embed them into the ROS message before publishing.

[rakshith95]

Thank you for your response. I will update here, after attempting the above. Closing this now