QGeoPositionInfoSource and QNmeaPositionInfoSource

Ferni

Hi guys!

I'm trying to get GPS data from my Android device and I experienced some strange behavior. To get GPS data I used QGeoPositionInfoSource. Altough I set UpdateInterval to 500ms, I receive an update every ~20 seconds. That works when I use AllPositioningMethods (maybe I don't have in my house a good GPS signal but I have a great WiFi signal)

Then I try to reproduce a GPS log with NMEA messages and in this case I have 2 different problems:

I cannot read my log (probably a format problem, doesn't really matter)
If I set an updateInterval, I can only read ONE message. If I don't set it, I read the entire file without delay between messages.

Am I the only one who has these problems? Am I doing something wrong?

    source = QGeoPositionInfoSource::createDefaultSource(this);
    if (source) {
        connect(source, SIGNAL(positionUpdated(QGeoPositionInfo)),
                this, SLOT(positionUpdated(QGeoPositionInfo)));

        source->setUpdateInterval(1000);
        source->setPreferredPositioningMethods(QGeoPositionInfoSource::AllPositioningMethods);

        source->startUpdates();
    }

    if(source2) {
        source2->createDefaultSource(this);
        QFile* logSource = new QFile(":/logs/nmealog.txt");
        source2->setDevice(logSource);
        source2->setUpdateInterval(500);


        connect(source2,SIGNAL(positionUpdated(QGeoPositionInfo)),
                this,SLOT(positionUpdated2(QGeoPositionInfo)));

        source2->startUpdates();

My log file was taken from geoflickr example.

Ferni

Ok, I went out and tested my GPS source. I could get messages every 1 second and that was fantastic.
I have two question now:

Why 1 second is the limit? Can you read GPS with a frequency of 2Hz or 5Hz? I'd like to track the position of a car and if the speed is 15km/h, I get the position every 4 meters. Where could I find GPS' precision? Maybe the resolution is 10 meters and get position once per second is just fine.
When I'm using AllPositioningMethods, I could get GPS every 20 seconds as I described before. Is this some kind of timeout or what is the problem? My configurable update interval works fine with SatellitePositioningMethods when I go out and get a strong GPS signal.

Thanks!
Fernando

Ferni

Update:

The second part of my original post is related to this unresolved bug.