How to fuse Rtabmap localization data into robot_localization package?

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Hi there,

I was working on a project using CLEARPATH Jackal UGV as the platform to do the indoor test. So I did not use GPS data. The sensors I used are wheel encoder, onboard IMU, and Kinect v2 as the only external sensor. The mobile robot has the robot_localization package inside and I used Rtabmap to generate the map. When I switched to localization mode, I want to use r_l to generate a better and high rate pose output since the frequency of rtabmap is very low. I have a Vicon motion capture system as the ground truth.

I checked the published topic of rtabmap. Only visual_odometry has the nav_msgs/Odometry topic which meets the r_l supported fusing topic type. And rtabmap has a published topic called rtabmap/mapGraph which contains the geometry_msgs/Pose. But this topic does not contain covariance.

I am wondering if there is a way to fuse rtabmap into robot_localization. Or it is impossible to do that. I read a lot of questions on answers.org.org , and most of them used r_l as the odometry filter fusing wheel encoder and IMU, the output odometry/filtered topic will then be fused into the rtabmap.

Thanks a lot!