shared map frame: how do we define it?

[aldoteran]

This is just a reminder to keep us from forgetting the issue of how to define a shared map frame between the robots. The simulator hinges upon the fact that Unity provides the origin of the map frame as a TF from utm->map_gt.

• But how will this work when there's no allmighty Unity to tell us to where that map frame is?
• Do we let the robots define their own map frame under their namespace if there's no map server to sync them? e.g. lolo/map and sam/map.

Food for thought!