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.
TTFN
Ken Yale
