PositionChanged event gives the old location details when application is restarted - windows-phone-7

Question

I have the below code which works fine except that it gives the last location details it tracked when application is restarted.
And it gives the correct location details after I click on btnGetLocationDetails button 2 or 3 times.
Any idea how I can fix this issue so that every time app is launched user doesn't need to click on this button 2 or 3 times to get the correct current location?
Code:
public partial class MainPage : PhoneApplicationPage
{
GeoCoordinateWatcher watcher = null;
Location location=null;
private void btnGetLocationDetails_Click_1(object sender, RoutedEventArgs e)
{
watcher = new GeoCoordinateWatcher(GeoPositionAccuracy.High);
if (watcher.Permission == GeoPositionPermission.Granted)
{
watcher.MovementThreshold = Convert.ToDouble("100");
}
watcher.PositionChanged += new EventHandler<GeoPositionChangedEventArgs<GeoCoordinate>(watcher_PositionChanged);
// PositionChanged events occur whenever your position changes
watcher.StatusChanged += new EventHandler<GeoPositionStatusChangedEventArgs>(watcher_OnStatusChanged);
watcher.Start();
}
void watcher_PositionChanged(object sender, GeoPositionChangedEventArgs<GeoCoordinate> e)
{
//get the coordinates
location = new Location();
location.Latitude = e.Position.Location.Latitude;
location.Longitude = e.Position.Location.Longitude;
location.Altitude = e.Position.Location.Altitude;
}
void watcher_OnStatusChanged(object sender, GeoPositionStatusChangedEventArgs e)
{
if (e.Status == GeoPositionStatus.Disabled)
MessageBox.Show("The location service is turned off.");
else if (e.Status == GeoPositionStatus.NoData)
MessageBox.Show("No location data is available. ");
}
}