Problem with Geolocation

Hello ,

I have a trouble with geolocation and showing my current position on 
map. I use HTML5 Geolocation API to get data from about my position, and 
always location is wrong for about 20 meters. After couple of refresh on 
the same page I always get a new position. I tested Google example of 
using geolocation on this link 
https://developers.google.com/maps/documentation/javascript/examples/map-geolocation, 
and it's the same problem. My GPS is turned ON, everything work well but 
I always receive wrong position. Can anybody help me , or explain me 
what is going on with HTML5 Geolocation API.
My Application also use the same code from Google example above.

Regards !