>>273499797
That's how all headsets work, it's just that some have better IMUs (combination of gyroscope, magnetometer, and accelerometer) and algorithms to handle what happens when the secondary frame of reference (cameras, LH, etc) has been lost. And some may have more reliable secondary references that cover a larger volume (as is the case when comparing 2 camera WMR to 5 camera Rift S), therefore reducing the amount of time that one is likely to spend in a state of IMU-only data.