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  1. #1
    Registered User
    Join Date
    Apr 2013
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    3

    Location service accuracy

    Don´t know if i´m doing anything but the accuracy in the location services are just crap on my lumia 920.
    Doesn´t matter what I do. The updates are very slow and the position service are always using the cellular network to determine position.

    Code:
    geolocator.MovementThreshold = 1; // The units are meters.
                //geolocator.ReportInterval = 10;
                //geolocator.DesiredAccuracyInMeters = 1;
                geolocator.DesiredAccuracy = PositionAccuracy.High;
    Was trying to build racing timer to determine how long it takes to drive 1/4 and 1/8 miles.
    Not a chance that it will work as it takes up to 10 seconds between the updates even when I have set the movementthreshold to 0 or 1 meters.

    Is there any possibility to only use the GPS in the location service?

    / Jonas

  2. #2
    Nokia Developer Moderator
    Join Date
    Mar 2003
    Location
    Lempäälä/Finland
    Posts
    29,170

    Re: Location service accuracy

    I have never had problems with the location accuracy really, my codes could be found from: https://projects.developer.nokia.com/WP8MapsExamples . There are separate examples fro Geolocator & GeoCoordinateWatcher but in gneral I have not seen them working too much differently in the end.

    anyway, do you have working internet conenction in the device ? the AGPS requires connectivity, and normal GPS is really slow to get initial position. Also I hope you udnerstand that GPS does not really work indoors, so you would need to test it outside, where you would have clear visibility to the sky.

  3. #3
    Registered User
    Join Date
    Apr 2013
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    3

    Re: Location service accuracy

    But is there a way to set the location service to only use gps?

    Guess I have to pull coordinates constantly to check if it´s GPS data and then make the functionality availiable in my app if the gps is active.

    As it´s a race timer im building the accuracy is very important. I have to get the coordinates to calculate the distance travelled at least 2 times every second.

  4. #4
    Nokia Developer Moderator
    Join Date
    Mar 2003
    Location
    Lempäälä/Finland
    Posts
    29,170

    Re: Location service accuracy

    basically you could see the docs for the API:
    http://msdn.microsoft.com/en-us/libr...tewatcher.aspx
    http://msdn.microsoft.com/en-in/libr...ion.geolocator

    As far as I can see, both APIs are not providing any direct way on forcing the GPS on, You could try to set the DesiredAccuracy to High, then it would use GPS when it would be available, though it likely resorts to other methods when GPS is not available. anyway, your logic could of course just ignore any results which is not accurate enough.

  5. #5
    Regular Contributor
    Join Date
    Nov 2009
    Posts
    200

    Re: Location service accuracy

    Quote Originally Posted by Dabit View Post
    I have to get the coordinates to calculate the distance travelled at least 2 times every second.
    I don't think it's possible to get 2 updates/second. Typical GPS receiver updates only once every second.

  6. #6
    Registered User
    Join Date
    May 2013
    Posts
    2

    Re: Location service accuracy

    Quote Originally Posted by Dabit View Post
    Don´t know if i´m doing anything but the accuracy in the location services are just crap on my lumia 920.
    Doesn´t matter what I do. The updates are very slow and the position service are always using the cellular network to determine position.

    Code:
    geolocator.MovementThreshold = 1; // The units are meters.
                //geolocator.ReportInterval = 10;
                //geolocator.DesiredAccuracyInMeters = 1;
                geolocator.DesiredAccuracy = PositionAccuracy.High;
    Was trying to build racing timer to determine how long it takes to drive 1/4 and 1/8 miles.
    Not a chance that it will work as it takes up to 10 seconds between the updates even when I have set the movementthreshold to 0 or 1 meters.

    Is there any possibility to only use the GPS in the location service?

    / Jonas
    Hi,

    as others have stated, the refresh rate of the GPS unit in the windows phone is 1Hz. I've been developing a lap timer and I can confirm this absolutely, as I've used a timer service to write data to the log file while logging GPS position. It doesn't matter what the interval for the call to the logger is, the GPS positions only update 1 time per second.

    There is a way to pre-start the GPS service when the application loads to have it warmed up.

    The only other advise I can offer is to construct the GeoCoordinateWatcher with GeoPositionAccuracy.High:

    Code:
    private GeoCoordinateWatcher _watcher = new GeoCoordinateWatcher(GeoPositionAccuracy.High);        
    ...
    _watcher.MovementThreshold = 1.0;
    var gpsObservable = CreateObservableGeoPositionWatcher();
       gpsObservable
       .ObserveOnDispatcher()               
       .Subscribe(OnPositionChanged);
    best luck,
    mike

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