On Sat, Oct 16, 2010 at 5:12 AM, Cedric Pradalier wrote: > Actually, the standard coordinate frame for flying system is with Z down > (it allows standard compass angle to be coherent with the X,Y motion). > For this reason, > I'm voting in favour of a Z down coordinate system for the AR-Drone. > > However, I agree that I would be suprised without  x forward, y > sideways, and yaw around z.... > > As soon as we have velocity control on the CoaX helicopter, our control > will definitely be like that. I realize that the standard aerospace orientation is "upside-down" compared to the standard robotics orientation as defined in REP 103. http://www.ros.org/reps/rep-0103.html#axis-orientation Since the intent of the ROS community is to share code, ignoring REP 103 is a mistake. Your vehicle would display upside-down in rviz, for example. But, note that there is already a documented exception for use with camera frames (and an "_optical" suffix). If it is really so important to use the aerospace convention, you should propose a similar modification to REP 103 and get approval from the whole community. Maybe an "_aerial" suffix would be appropriate. To me, that seems clumsy and unnecessary. You could use standard ROS frame transform conventions yet still communicate with humans using idiosyncratic aerospace terminology. --  joq