Finding distance using accelerometer in iPhone

Question

Please suggest some beginning point in this process of finding distance displaced by an iPhone. The requirement of accuracy in current system is in cm, and displacement can be in 3D.

What I have already done is

1. Tried using sound to calculated distance between between 2 iPhones, but I need distance calculation with one iPhone only, i.e need displacement.

2. Tried CMMotionManager and its accelerometer data, but values received is helpless.

I think I need a good filter to get useful data out of that junk. I already used Kalman Filter and gone through link

iphone accelerometer speed and distance,

How to calculate distance using accelerometer using iphone sdk?,

How do I measure the distance traveled by an iPhone using the accelerometer?,

Basic calculus behind this problem is in the expression

Tried DCT-II algorithm and Multidimensional DCTs to filter data.

I dont know what did I miss, or where should I go from here, as it is hard to believe that no one has used accelerometer for such an accuracy, because there are so many practical examples of it being used for greater accuracy.

Please provide me some pointer that suggest some way out of current situation.

Answer 1

You can't achieve cm accuracy. The reason is, surprisingly, the orientation error.

The above link contains some tips what you can do if you need displacement.

An even better alternative is to use orientation in you application, if you can.