The way I see this is as small box that could be added to the user's environment and that would track the head's position.

2 way of doing this: a) rework the VR920 and add something on it that would track the head movement (ie: the intelligence would be embeded in the helmet) b) add a separate box with markers to add to the helmet (the inteligence would be in the added box)

a) has the advantage of integration (no added cables)

b) has the advantage of being a component that can be added to existing VR920

Track IR offers 6DOF as well.  Luckily I have both and they compliment each other well, however it's an expensive solution and I wanted to sell my track ir.

While conducting archaelogical remote sensing surveys, I've often used a Cesium magnetometer that is configured as a dual-sensor gradiometer.  Now, these devices are most likely far more sensitive than anything you could fit into a HMD, but the concept is the same; one sensor acquires one set of readings while the second sensor's readings are simultaneously used to filter out what are natural fluctuations.

It seems as though a similar device configuration could be used for the VR920, where a device is connected via USB and mounted 6" above your monitor or whatever, and then the Calibrator application uses that secondary reading to correct for the visor.

I have no clue what they cost, so perhaps they are cost-prohibitive.

"Living life one humorous day at a time."