如何实现连续准确的Windows Phone 8 GPS跟踪

Question

I tried to make an app that Continuously fetch location windows phone 8.

The following code is used to fetch location.

                geolocator = new Geolocator();
                geolocator.DesiredAccuracyInMeters = 30;
                geolocator.ReportInterval = 15000;
                geolocator.StatusChanged += geolocator_StatusChanged;
                geolocator.PositionChanged += geolocator_PositionChanged;

When gps is getting normally everything work fine.

But Once the gps location is not availabile the Geolocator stops the location fetching.(That is when the device back to gps area the geolocator_PositionChanged not called)

I tried to to create a new geolocator object in geolocator_StatusChanged() as per this blog ( geoposition advanced tracking scenarios for windows phone 8 )

  case PositionStatus.NoData:
              geolocator = new Geolocator();
              geolocator.DesiredAccuracyInMeters = 30;
              geolocator.ReportInterval = 15000;
              geolocator.StatusChanged += geolocator_StatusChanged;
              geolocator.PositionChanged += geolocator_PositionChanged;

              status = "no data";
              break;

But it also not worked. Please guid me how to ensure continues availabilty of gps data?

Another point noticed that Once the gps source changed to Cellular it never come back to use the Satalite as gps source ( The cellular source returns least accurate gps values). So how i can specify the gps source in windows phone 8?

Testing done on the device: Nokia lumia 520

Answer 1

I have a fully working windows phone location client that I have tested out on the Lumia 520. Please test it out and let me know what you think:

https://github.com/nickfox/GpsTracker/tree/master/phoneClients/windowsPhone

You shouldn't be as concerned with the location source as with the accuracy. If a source is meeting your required accuracy (whether its gps, wifi or cell), who cares where it comes from. Test your location to make sure it meets your accuracy needs:

if (args.Position.Coordinate.Accuracy < 100.0) {
// do something with location
}