After rosrun ekf_localization_node and navsat_transform_node, I got warning like this: [ WARN] [1494926574.013925839]: Could not obtain transform from /gps to base_link. Error was Invalid argument "/gps" passed to lookupTransform argument source_frame in tf2 frame_ids cannot start with a '/' like:
Originally posted by DaDaLee on ROS Answers with karma: 113 on 2017-05-16
Post score: 0
This means you probably haven't defined the gps link in your URDF. The gps link should be a link defined on your robot at the location where your GPS is mounted. Make the joint from the gps link to its parent link a fixed joint, and the transform should then be available to navsat_transform_node.
Originally posted by ufr3c_tjc with karma: 885 on 2017-05-16
This answer was ACCEPTED on the original site
Post score: 0
Comment by DaDaLee on 2017-05-17:
Well, it sounds reasonable, but I don't know how and where to define that. Would you mind showing me the detail ? I'm new to navsat_transform_node, thank you so much!
Comment by ufr3c_tjc on 2017-05-17:
Just add a link in your URDF file called gps. Will give you the details when I can access a PC in an hour or so.
Comment by DaDaLee on 2017-05-17:
So nice of you. You mean add context like " gps_frame_id : gps " in ekf_template.yaml?
Comment by ufr3c_tjc on 2017-05-17:
Add this to your URDF file:
<link name="gps"/>
<joint name="gps_to_base_link" type="fixed">
<parent link="base_link"/>
<child link="gps"/>
<origin xyz="0 0 0" rpy="0 0 0"/>
</joint>
Comment by DaDaLee on 2017-05-18:
Thank you so much