GPS计算Windows Phone 7上两点之间的距离

我正在使用 GPS 来计算两点之间的距离，即我使用 Windows Phone 作为卷尺，但当我开始时，我实际上没有得到正确的值，即使我站着不动，它也给了我数百米

这是我的代码

      myWatcher.StatusChanged += new EventHandler<GeoPositionStatusChangedEventArgs>(myWatcher_StatusChanged);
        myWatcher.PositionChanged += new EventHandler<GeoPositionChangedEventArgs<GeoCoordinate>>(myWatcher_PositionChanged);
        myWatcher.MovementThreshold = 1;   

void myWatcher_PositionChanged(object sender, GeoPositionChangedEventArgs<GeoCoordinate> e)
    {
        double tempf = e.Position.Location.Latitude;
        double temps = e.Position.Location.Longitude;
        if (count2 == 0)
        {
            FirstLocation = new GeoCoordinate(tempf, temps);
            count2++;
        }
        else
        {
             double distanceInMeter;
            GeoCoordinate currentLocation;
                currentLocation = new GeoCoordinate(tempf, temps);
                distanceInMeter = currentLocation.GetDistanceTo(FirstLocation);                   

                if (App.flag == 0)
                {
                    textBlock1.Text = distanceInMeter.ToString() + " m";
                    double distanceInCm = distanceInMeter * 100;
                    textBlock2.Text = distanceInCm .ToString() + " cm";
                }
                else if (App.flag == 1)
                {
                    double distanceInInch = distanceInMeter * 39.3701;
                    textBlock1.Text = distanceInInch.ToString() + " in";
                    double distanceInFoot = distanceInMeter * 3.28084;
                    textBlock2.Text = distanceInFoot.ToString() + " ft";
                }
        }

    }

GPS充其量只是accurate至3米。更可能的误差是 5 - 10 米。

你将不得不augment您的 GPS 读数以获得更好的准确性。