Copter X-Y-Z - Which is which?

ArduCopter Copter 3.2
3

Hi,

I’m sorry but I was wrong. So for whoever reads this:
Ardupilot uses NED (North - East - Down) frame of reference. See this:
pixhawk.org/dev/know-how/frames_of_reference

Copy pasted what’s important:
NED Coordinate System:

  • The x axis is aligned with the vector to the north pole (tangent to meridians).
  • The y axis points to the east side (tangent to parallels)
  • The z axis points to the center of the earth

There is also Body Fixed Frame:
Body Fixed Frame (Attached to the aircraft)

  • The x axis points in forward (defined by geometry and not by movement) direction. (= roll axis)
  • The y axis points to the right (geometrically) (= pitch axis)
  • The z axis points downwards (geometrically) (= yaw axis)

In order to convert from Body Frame to NED what you need to call this function:

copter.rotate_body_frame_to_NE(vel_vector.x, vel_vector.y);

Cheers
Nitay

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