Re: [time-nuts] GPS Valid Fix Detector
I worked wtih a GPS module that would spit out all zeros for lat/long if there was no fix, and another that would spit out the coordinates for the manufacturer's office. It'll probably be hard to weed out every special case, but with the code, any of us can easily just modify it for our own needs. Thank you for taking the time to at least get *me* started :) You saved me a lot of trouble. -Bob On Mon, Nov 24, 2008 at 3:00 AM, Ulrich Bangert <[EMAIL PROTECTED]>wrote: > 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 -- time-nuts@febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts > > and > > follow the instructions there. > > > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS Valid Fix Detector
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 -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts > and > follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
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 NMEA P> 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,1.116,104.33,120107,,,A*6A Trimble Pathfinder Pro XR $GPRMC,050945.00,A,3504.227794,N,13545.810149,E,000.0,57.1,140302,6.5,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,1.177,229.34,080705,,,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 -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] GPS Valid Fix Detector
Greetings, For those interested in a very simple means of determining if the NMEA data stream from a GPS receiver contains valid fix data, I offer design details for a "Valid Fix" detector that runs in a Microchip 12F629, an 8-pin DIP device. No other components are required if the GPS receiver provides CMOS output levels: http://www.ni6e.com/time/GPS_Valid_Fix.html Regards, Peter ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
