Do the latest Roombas have GPS? If not, then they don’t really have a way to connect your floor plan with a physical location. If they do … well, I don’t think GPS would be much use for interior navigation. I think its only use would be to locate the Roomba in the world. (It can get the time from the wifi router.)
I guess the next step would be to watch the traffic between the Roomba and the mothership.
