Ubuntu 20 + Python3 setup

I am running this as you want configured, but also with double aruco markers.

Try running the sim_vehicle first and wait a bit, then in a 2nd terminal run gazebo and it should connect.

…/Tools/autotest/sim_vehicle.py -f gazebo-iris

roslaunch gazebo_ros iris_world.launch

or in my case:

roslaunch gazebo_ros iris_world.launch world_name:=“2_arucos.world”

Also note: https://community.dojofordrones.com/t/full-gz-sim-on-22-04-lts/805/6