track small movements of iphone with no GPS

Question

I have to write an application for iphone that tracks the movement of the iphone itself, given its initial position, without ever using GPS. That is, I can only use data pro

Answer 1

If you integrate the acceleration twice you get position but the error is horrible. It is useless in practice.

Here is an explanation why (Google Tech Talk) at 23:20. I highly recommend this video.

I answered a similar question here and here.