Acc/Gyro/Mag axis reference - which is which?

[mungewell]

I've been trying to implement the AHRS with the sensors from the PlayStationVR headset, and getting confused about which axis should be which.

From reading the sensor values, as arrays, I have:

Structure of the PSVR sensor: Gyros (when wearing headset normally). 1 - yaw, +ve right hand forward 2 - pitch, +ve look up 3 - roll, +ve right hand down Accelerometers, largest when 'x' is highest point 1 - top+, bottom- 2 - right+, left- 3 - front+, back-

And on the other end, when the rendering the scene from the output of Madgewick I know that the following are true (tested by setting during init and not updating the AHRS):

Quaternion that points directly forward refq = Quaternion((1,0,0,0))

Quaternion pointing/pitched directly up refq = Quaternion.from_angle_axis(np.pi/2,1,0,0)

No matter how I've tried swapping various axis I have not yet reached a working system, it either 'moves' incorrectly or the Quaternion ends up pointing in the wrong direction....

Can someone/any provide a reference for how the axis should be arranged?