How to export pose for mavros from RTABMAP?

[sean819]

Hi Mathieu,
I am doing a project that is getting pose information for MAV to do navigation. And our pixhawk will be connected like this:

So I have two ideas that one way is combining the data from visual odometry (camera ASUS Xtion Pro live) with IMU by MSF_EKF, and the other way is getting the pose from rtabmap for mavros. My problems are following:
(1) Which way is better to get the pose?
(2) I try to export pose for mavros but have no idea how to do it.How can I get pose information from RTAB-MAP?
Thanks

[matlabbe]

Hi,

First, is your application indoor or outdoor? Be aware that the Xtion doesn't work outdoor, otherwise you may want to look for a stereo camera.

1) Your first approach would give you odometry poses, as the second will correct the odometry poses on loop closure detection. You got:

sensors ----> odometry (/odom to /base_link) ----> rtabmap ----> updated TF /map to /odom

2) You can use TF for convenience to get the current pose in /map frame (/map -> /odom -> /base_link). What you can do is to subscribe to your odometry output to know when a pose is available (in /odom frame), then use TF to get it in /map frame.

cheers