Not possible to do multiagent simulation with external odometry

[TannerGilbert]

Bug report

Issue details

I followed the odometry section of ROS 2 interfaces and the Cartographer SLAM with ROS 2 in SITL to get the simulation with external odometry. Then I wanted to extend my multiagent implementation (ArduPilot/ardupilot_gz#67) to also work with external odometry but I don't see how it's possible as I have only one /ap/tf and I didn't find anywhere in ardupilot/Tools/ros2 where I can add a namespace.

Version
Tested on Ubuntu 22.04, ROS 2 Humble and Gazebo Harmonic following https://ardupilot.org/dev/docs/ros2-gazebo.html

Platform
[ ] All
[ ] AntennaTracker
[ x ] Copter
[ ] Plane
[ ] Rover
[ ] Submarine

Airframe type
Iris

[TannerGilbert]

@srmainwaring sorry for the many issues but I think the above described problem is related to the micro-ROS-Agent and I saw that you have a fork of it.

I think the problem with the topic not being remapped is that the namespace that is added in launch.py is not accepted/used by the micro_ros_agent node.

Related issues and draft PRs:

• A way to set a ROS namespace in the Agent micro-ROS/micro-ROS-Agent#126
• Add namespace override micro-ROS/micro-ROS-Agent#145

I tried the draft PR but unfortunatelly it only seems to add the namespace to the node name and not to the topics.

Testing setup:

• Ubuntu 22.04
• ROS 2 Humble