ROS no data to GCS

Hello,i installed Cartographer with ros to a raspberry pi 3b+.I followed this commercial manual https://ardupilot.org/dev/docs/ros-cartographer-slam.html.I cannot see any data flow from ros to the GCS in the messages section and no visual position estimate in Mavlink inspector.Data is flowing from pixhawk to rpi3 and commands such as rosrun mavros mavsys mode -c 0 work.Can anyone help? Thank you in advance