GPS data from gllin

Jonathon Suggs jsuggs at
Mon Aug 6 22:11:15 CEST 2007

Ken Yale wrote:
> Hello,
> The GLLIN sends NMEA sentences to named pipe  "/tmp/nmeaNP".
> The OMGUI uses this output to plot positions, satellite strength, etc.
> on various OMGUI test panels.
> Close your handle to /tmp/nmeaNP to stop the GLLIN (if it was opened
> with "-np" option).
> Below is a typical NMEA output sequence from the GTA01 showing the
> position (RMC,GGA), time (UTC format)  (RMC,GGA), satellites used (GSA),
> satellites tracked (GSV), satellite signal strength (GSV), and satellite
> position (GSV), type of fix (GSA), and various other details (GGA
> especially has lots of miscellaneous information).
> Google "NMEA" and you'll find excellent tutorials about NMEA.  (Be sure
> not to type too fast and end up with "NEMA" which, among other things,
> is a medical-imaging file exchange standard.)
> $GPGGA,230648.00,3716.309458,N,12156.790892,W,1,07,0.5,040.0,M,-0.537000
> ,M,0.0130515,0130*7C
> $GPRMC,230648.00,A,3716.309458,N,12156.790892,W,005.9,188.0,060607,,,A*4
> 1
> $GPGSV,2,1,08,23,69,004,37,20,52,174,44,25,49,260,44,13,46,314,30*70
> $GPGSV,2,2,08,16,42,064,35,04,14,292,34,01,12,096,30,27,25,250,16*77
> $GPGSA,A,3,01,04,13,16,20,23,25,,,,,,1.1,0.5,1.0*32
> $GPGGA,230649.00,3716.307825,N,12156.791167,W,1,07,0.5,040.0,M,-0.537000
> ,M,0.0130515,0130*77
> $GPRMC,230649.00,A,3716.307825,N,12156.791167,W,006.1,188.0,060607,,,A*4
> 1
> $GPGSV,2,1,08,23,69,004,35,20,52,174,43,25,49,260,43,13,46,314,28*7B
> $GPGSV,2,2,08,16,42,064,35,04,14,292,34,01,12,096,28,27,25,250,27*7C
> $GPGSA,A,3,01,04,13,16,20,23,25,,,,,,1.1,0.5,1.0*32
> The OpenMoko team will plug the GLLIN into the GPSD (see module
> omgui/gllin.cpp for sample GLLIN start/stop code to use as the basis for
> the GPSD).   I hear the DBUS link planned for GPS information
> distribution beyond the GPSD multi-cast is done.
> Ken Yale
Thanks for the info, I'm looking into the gpds documentation right now.  
I'm somewhat familiar with DBUS, but will need to get my hands dirty 
with it before I feel truly comfortable.  Any DBUS and/or GPS gurus out 

I know possibly premature, but what would be the "correct" way to get 
gps information?

You can get the raw output like is demonstrated in the wiki

Or you could call d-bus methods (ie turnOn, turnOff, curPosition, 
curElevation, curSpeed, etc).  Do we have any idea what that address 
would be and/or has anyone worked on those interfaces/methods?

I would think something like the dbus interface could make for "cleaner" 
more (re)usable code, plus you could hide some of the underlying 
complexities in the gpsd setup.

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