Track position Indoor (with smartphone) [duplicate]

This question already has answers here: Closed 11 years ago.

Possible Duplicate:

Indoor Positioning System based on Gyroscope and Accelerometer

Very simple question for you guys. Suppose I wanted to track my location accurately with no real reference points (gps). And what I mean by that the only thing i know is my location (0,0) on a 2-dimensional map, is it possible with use of a gyro and accelerometer to track my position as I walk away from that point?

I have read quit a lot of paper on that subject but no one is clearly telling how this could be realized. I especially had a look to that video http://www.youtube.com/watch?v=C7JQ7Rpwn2k (Google talk) It's about how to integrate all the sensors.. it's really nicely explained, but once again... After having watched that video I have still no ide开发者_如何转开发a (formulas? Technique? etc..) how to use those sensor to track my position

Can someone guide me too some good tutorial? About calculate the next position from the angle, velocity etc. ?

Thank you.

---

You need to understand that accelerometer measures acceleration - thus if you move with a constant walking speed, the accelerometer will not detect any movement. It will only detect if you start walking faster/slower. Distance can't be tracked with an accelerometer. You could only very very roughly estimate the position. Maybe also counting the steps with a sort of "pedometer" algorithm that would count your steps by measuring the cyclic vibrations while walking. You will still need the direction when you are going - which could be only roughly estimated with the accelerometer.