Oculus - Get rotation relative to RealWorld

So what I want to do is combine the Oculus with tracking of LEDs in a room full of cameras to have the user walk around freely. I need to somehow get the Oculus orientation relative to real world coordinates. Is there a way to get the rientation relative to the north pole or something similar?
I could calibrate the Oculus by forcing the user to look straight and then catch the orientation and assume its rotated (0,0,0) compared the the body of the player, but that would force me to recalibrate very often and will end up being unprecise.

Can anyone help me out here please?

Magnetometer, on an IMU…hmmm the Rift has a Mag…you should be a able to get a fixed reference anyway that is repeatable.

I just dont really know how. I tried to google it already, but couldnt find anything helpful. From what I thought, the rift is settings its base rotation to 0,0,0 on every game start, or am I wrong about that?