The getState() method of the PositionSensorVRDevice interface returns the current state of the position sensor for the current frame (e.g. within the current window.requestAnimationFrame callback) or for the previous frame, contained with a VRPositionState object. This is the method you'd normally want to use, versus PositionSensorVRDevice.getImmediateState.
The resetSensor() method of the VRDevice interface can be used to reset the sensor if desired, returning the position and orientation values to zero.
The hardwareUnitId read-only property of the VRDevice interface returns the distinct hardware ID for the overall hardware unit that this VRDevice is a part of. All devices that are part of the same physical piece of hardware will have the same hardwareUnitId.
The maximumFieldOfView read-only property of the VREyeParameters interface describes the maximum supported field of view for the current eye.
The minimumFieldOfView read-only property of the VREyeParameters interface describes the minimum supported field of view for the current eye.
The recommendedFieldOfView read-only property of the VREyeParameters interface describes the recommended field of view for the current eye — ideally based on user calibration.
The renderRect read-only property of the VREyeParameters interface specifies the viewport of a canvas into which visuals for the current eye should be rendered.
The hasOrientation read-only property of the VRPositionState interface returns a boolean indicating whether the VRPositionState.orientation property is valid (i.e. if the hardware is currently registering a valid orientation). If it is false, the orientation property will return null.