Peter, in general NMEA decoding involves
1) Message type detection 2) End of message detection 4) Checksum test 5) Looking for what is to be found between comma N and comma N+1, having in mind that there may also be NOTHING. Best regards Ulrich Bangert > -----Ursprungliche Nachricht----- > Von: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Im Auftrag von Yuri Ostry > Gesendet: Montag, 24. November 2008 04:21 > An: Peter Putnam; Discussion of precise time and frequency measurement > Betreff: Re: [time-nuts] GPS Valid Fix Detector > > > Hello, > > Monday, November 24, 2008, 1:08:45, Peter Putnam wrote: > > P> Greetings, > > P> For those interested in a very simple means of determining if the > P> NMEA data stream from a GPS receiver contains valid fix > data, I offer > P> design details for a "Valid Fix" detector that runs in a Microchip > P> 12F629, an 8-pin DIP device. > > P> No other components are required if the GPS receiver provides CMOS > P> output levels: > > P> http://www.ni6e.com/time/GPS_Valid_Fix.html > > P> Regards, > P> Peter > > > Looks like your firmware will need some correction, as there > is a lot of NMEA variations... > > Below is examples of GPRMC sentences from several different > GPS receivers. You'll need to pick character after second > comma, not by particular offset, to be compatible. > > > uBlox LEA4A (firmware 4): > $GPRMC,214541.00,A,5558.55936,N,03709.54595,E,1.116,104.33,120 > 107,,,A*6A > > Trimble Pathfinder Pro XR > $GPRMC,050945.00,A,3504.227794,N,13545.810149,E,000.0,57.1,140 > 302,6.5,W,A*12 > > Garmin GPS III Plus > $GPRMC,031655,A,3404.456,N,13531.788,E,000.0,360.0,110101,006.8,W*6D > > Garmin GPSMAP 76S > $GPRMC,040014,A,4242.0410,N,14134.2795,E,1.4,51.0,010802,8.0,W,A*35 > > Blue Logger GPS (Something from Japan) > $GPRMC,021803.751,A,3501.5666,N,13546.9457,E,0.00,212.31,110604,,*07 > > uBlox SBR-LS (firmware 3.01) > $GPRMC,051250.00,A,5558.55523,N,03709.54211,E,1.177,229.34,080 > 705,,,A*6E > > GlobalSat BT-338 (SiRF) > $GPRMC,100643.000,A,5522.9036,N,03710.1282,E,0.16,119.11,200507,,*0D > > > > > > -- > Best regards, > Yuri mailto:[EMAIL PROTECTED] > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts > and > follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
