On Tuesday 28 July 2015 13:22:04 Edward Sutton wrote: > Thank you Alex, > > On Jul 28, 2015, at 3:05 AM, Blasche Alexander <alexander.blas...@theqtcompany.com<mailto:alexander.blas...@theqtcompany.com>> wrote: > >I want to output NMEA strings that look like this: > >$GPGGA,123519,4807.038,N,01131.000,E,1,08,0.9,545.4,M,46.9,M,,*47 > >Maybe QNmeaPositionInfoSource has some way to output the raw source strings > >that it reads? > Well, the class' purpose is to process an incoming NMEA string. If I just > want to output the raw strings then we wouldn't have to wrap the QIODevice > providing the NMEA strings. We would directly print the content from the > QIODevice .... > > If you want to convert the output from a regular QGeoPositionInfoSource to > NMEA then you would have to write the conversion code yourself. There is no > support for it in Qt. It shouldn't be too difficult though as > QNmeaPositionInfoSource provides a template for the reverse already. > > -- > Alex > > > I need to create the NMEA string from the QGeoPositionInfoSource properties > for 3 message types; GPGGA, GNGNS, and GLGNS. > > > My concern is many NMEA fields are not exposed. For example for GPGGA > number of satellites, HDOP, DGPS reference station, etc. I suppose I could > fake missing field values and see how the device works. For example time, > lat, lon, and fake the remainder to nominal fields. > > The alternative may be to make something similar to QtPositioning.java that > uses > GpsStatus.NmeaListener<http://developer.android.com/reference/android/locat > ion/GpsStatus.NmeaListener.html> instead of GpsStatus.Listener. That > appears to be much harder but would be a better solution in the long run. > > I think I will try faking missing fields first. For this application I am > not sure if our device even cares which satellite system the data is coming > from GPS or GLONASS. The Android device may be connected to one or the > other but I could always fake the output as GPGGA. > > Thanks Alex, > > -Ed > $GPGGA > > Global Positioning System Fix Data > > Name Example Data Description > Sentence Identifier $GPGGA Global Positioning System Fix Data > Time 170834 17:08:34 Z > Latitude 4124.8963, N 41d 24.8963' N or 41d 24' 54" N > Longitude 08151.6838, W 81d 51.6838' W or 81d 51' 41" W > Fix Quality: > - 0 = Invalid > - 1 = GPS fix > - 2 = DGPS fix 1 Data is from a GPS fix > Number of Satellites 05 5 Satellites are in view > Horizontal Dilution of Precision (HDOP) 1.5 Relative accuracy of > horizontal position Altitude 280.2, M 280.2 meters above mean > sea level > Height of geoid above WGS84 ellipsoid -34.0, M -34.0 meters > Time since last DGPS update blank No last update > DGPS reference station id blank No station id > Checksum *75 Used by program to check for transmission errors >
The usual method is that these fields are empty (just ",,"). Even standard GPS receivers send empty fields before they have a valid fix. -- Best Regards Reinhardt Behm _______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest