[time-nuts] NMEA Software

John Miles jmiles at pop.net
Thu Dec 20 23:04:25 UTC 2012

If you don't mind tinkering around with a Windows console application, you
can look at GPS.EXE, whose C source and executable are installed with the
current http://www.ke5fx.com/gpib/readme.htm package. This app is a test
scaffold for GNSS.DLL, a library that is meant to provide a dead-simple
runtime API for various GPS receivers.  

Right now GNSS.DLL has been tested only with an LEA-6 module over a virtual
COM port, but I would be curious to hear if it works with other NMEA sources
as well.  It basically just starts a background thread to listen for $GPGGA
sentences, and updates a structure with lat/long/UTC info that is shared
with the calling application.  The GPS.EXE console app initializes the DLL
based on the COM port spec passed on the command line, then watches for the
structure to be updated.  It dumps the lat/long coordinates to stdout once
valid fixes start to come through.

You can use a dumb terminal program as well, but NMEA sentences are not very
legible to a human reader.  At the other end of the complexity scale, a
generalized NMEA client API that's truly hardware-independent would be a
complicated beast (see http://catb.org/gpsd/NMEA.html ).   GNSS.DLL is sort
of an intermediate solution, aimed at being as simple as possible while
still being useful in real-world programs.

(Run GPS.EXE without any options to see the current usage notes.)

-- john
Miles Design LLC

> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-
> bounces at febo.com] On Behalf Of Rick Karlquist
> Sent: Thursday, December 20, 2012 2:06 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] NMEA Software
> I have an Outback S-Lite tractor GPS with a serial port with NMEA.
> Is there ready-to-use software to read out in lat/long
> from this port?  Maybe I can talk to it with hyperterminal
> and make it just keep sending lat/long once per second or
> something.  Is there a command set?
> I'd like to use this for laying out antennas, etc. (ie surveying).
> Rick Karlquist N6RK
> Martyn Smith wrote:
> >
> > Hi,
> >
> > Apologies if this has been asked 1000 times before.
> >
> > Is there any good software for reading the NMEA or Motorola binary code
> > out of a M12M.
> >
> > I have winoncore, but wondered if there was anything a bit more modern.
> >
> > Regards
> >
> > Martyn
> > _______________________________________________
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