GPS data from gllin

Ken Yale kyale at
Mon Aug 6 21:48:57 CEST 2007


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.)


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

-----Original Message-----
From: Jonathon Suggs [mailto:jsuggs at] 
Sent: Monday, August 06, 2007 11:49
To: Krzysztof Kajkowski
Cc: OpenMoko; openmoko-devel
Subject: Re: GPS data from gllin

Krzysztof Kajkowski wrote:
> Hi! I want to ask phase0 developers: what is the format of gllin 
> output data? I am trying to  convert it to google earth using gpsbabel

> but I have no clue what i could be. Most possible guess is NMEA but 
> the error for my location is about half of the world ;))) so I guess 
> this is not it...
> best regards
> cayco
This doesn't answer your question, but can someone send a dump of a GPS

Also, if an application is going to make use of GPS data, what is the
preferred method to get the data?  Directly from the device or is there
some type of multicast protocol that you need to subscribe to?

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