Q:

Short-term position tracking with IMU

I have researched quite a bit about short-term position tracking with an IMU, and can't really seem to find anything on it. A lot of people say it's impossible to track position with an accelerometer, but all this is in the context of long term position tracking. I'm just looking for something less then a second. 
I Googled around and found this video.
This shows doing it with an IMU, but when I take the double integral of the acceleration, its getting real messy. Any suggestions on how to approach this problem? Will a Kalman filter solve some of the issues? 

A:

The errors in position based on the double integrated accelerometer signal are related to: 

Drift of bias in the accelerometer signal. A small error in the estimated bias will lead to a position error that is exploding very fast (double integration).
Gravity. Unless the orientation of the accelerometer is exactly perpendicular to the gravity, there will be a component of the gravity in the accelerometer signal. 

Adding additional knowledge/measurements can help to reduce growth of your position error, e.g.:

Tracking the orientation of the accelerometer using gyro and/or magnetic sensor (9 DOF). If the orientation is known the gravity component in the accelerometer can be calculated and removed.
Detecting specific situations with known orientation or speed. In the case of the video, there could be a detection that the stone is flat on the board (vertical speed is zero, orientation is horizontal) or in one of the corners (position known, speed zero for some time).

This may be implemented using a Kalman filter.

