acceleration | x | ? |
y | ? | |
z | ? | |
accelerationIncludingGravity | x | ? |
y | ? | |
z | ? | |
rotationRate | alpha | ? |
beta | ? | |
gamma | ? | |
interval | ? |
alpha | ? | ➵ |
beta | ? | |
gamma | ? |
According to Apple's ref. (#2 below):
The angles of rotation do not represent the real world orientation.
They are defined as offset from an arbitrary direction.