title: iOS : Detect user location when App is back from Background
body: <p>I have a MKMapView &amp; I use it to display user's current location. It works normal when I first load it in the App. But when I press Home button to put the App to background &amp; call it back from background, the map prompts it is unable to find the user's location. </p>
  
  <p>I was thinking is the MKMapView takes time to search for user's location, and when I call it back from background, it does not have enough time to load the location service ?</p>
  
  <p>iOS5 SDK, xCode 4.3 is used.</p>