Accelerometer

I can testify that fusing higher latency absolute position sensors like the Hydra with the Rift accelerometer does improve responsiveness considerably.

I'm no signal processing expert but a naive EKF implementation was much better than raw position data. The devil is in the details with this sort of thing (like you probably don't want the average filtering applied by the Oculus SDK, and dealing with latency in predictive models is always tricky) but its definitely the way to go.

I should also point out that the true enemy is not position drift, but velocity drift. Ending up a little off center after moving around is only a serious problem in cockpit simulators, but estimating a small constant velocity when you are actually stationary is always bad.

Sorry for zerging this thread, but I am new to the Oculus and was also wondering if I could get the raw accelerometer data? Has anything changed since this was last answered?

In OVRDevice.cs there is a function:

public static bool GetAcceleration(ref float x, ref float y, ref float z)

I believe that is what you are looking for.