Re: Mapping and GPS Orientation Problems

Posted by jitoobias on Jun 07, 2021; 9:40pm
URL: http://official-rtab-map-forum.206.s1.nabble.com/Mapping-and-GPS-Orientation-Problems-tp8090p8161.html

Hi,
I sent this in an email directly to you last week but don't know if you got
it.

The GPS (GPS/fix) data is coming in at around 90Hz (continuously) but goes
through the Navsat Transform before going to my EKF to provide the
odometry/GPS topic, which is around 15 Hz.
Yes, ideally I would use the GPS fused data for odometry. My understanding
of the Robot Localization package is that the Map and Odom TF both provide
odometry for the vehicle. The map TF is discontinuous and the Odom TF is
continuous.

One thing I have done is subtracted my initial heading from the new heading
data coming through. This starts the GPS going in the correct direction but
still doesn't follow the map. I think that could be due to what you wrote
about the loop closures adjusting the map shape.
I also do have the GPS/topic going into RTAB-map but I don't think it does
anything.

I tried setting RTAB-Maps "map_frame = rtab_map" and "Odom_frame= datum"
and the map was created with the EKF and GPS following the map. The datum
frame got moved but I don't think that matters as that is there to provide
the initial GPS position of the vehicle within the map.

When I tried to localize with the same setup the GPS doesn't follow the map
correctly and the RTAB-map lines (neighbor and loop closure) are not
correctly positioned (I think not in the correct orientation).

If you can provide a cloud storage link, I'll upload the files and
hopefully, you can assist me that way.

Thanks again for all the help