iphone GPS - LocateMe

[tbui57]

I downloaded the LocateMe from Apple sample code to my iPhone. I tried it out in various cities in europe (geneva, zurich, salzburg, prague). The problem I have is that it take a long time for the iPhone LocateMe to return the correct coordinates, some time more than two hours of running this application. Once it returns the correct coordinates, subsequence invoking of LocateMe returns the correct coordinates within a few minutes.
Any one knows why it takes so long to calculate the coordinates in a new cities ? The program LocateMe returns "cannot determine the location" during this time.

Thanks in advance...