Build rtabmap from source following the instructions
Get imu_tools:
sudo apt-get install ros-noetic-imu-tools
Place rtabmap_gui.ini in /home/$USER/.ros/ and fix the first line in the file.
Perform simple IMU calibration:
rosrun imu_calib do_calib
# start camera and imu pub on SailMAV https://github.com/jwpleow/SailMAV_ROS_RPI (use correct branch for IMU)
# start rectifier and depth inference node https://github.com/jwpleow/stereo_libtorch_inference
roslaunch rtabmap_sailmav.launch