The global frame is such that the x,y origin is at the pinger, and z=0 is at the surface. Positive z is up. Yaw is relative to magnetic north. Pitch and Roll are relative to the gravity vector.
world- Global frame defined above
cobalt- The frame defining the sub's orientation relative to the
worldframe based upon the localization node output.
cobalt_sim- The frame defining the sub's orientation relative to the
worldframe based upon Gazebo's output.
A visual representation of the TF tree will be placed here in future.