On Tue, 30 Dec 2008 21:40:27 GMT, Unruh <[email protected]> wrote:
>George R. Kasica <[email protected]> writes: > >>>>>What am I doing wrong here when I add back GPS data to break this >>>>>thing??? >>> >>> >>>>Next step....I added back GPS NEMA data without the gpsd daemon (I >>>>don't pass the data out to anywhere so there's no real need for it) >>> >>>What does "I added back GPS NMEA" mean? What program did you use to do >>>that? What reads teh NMEA data and passes it on to ntp. >>Put the config lines back in ntp.conf so it would read the NMEA data. > >>>># ntpq -p >>>> remote refid st t when poll reach delay offset >>>>jitter >>>>============================================================================== >>>>xGPS_NMEA(0) .GPS. 0 l 13 16 377 0.000 -616.37 >>>>10.466 >>> >>>Looks to me like you could get rid of that offset with a fudge. >>What would be a good amount to use half the avg. erorr or ?? > >>>>I have good PPS and am getting GPS NEMA in as well but the offset for >>>>the NEMA data seems quite large....what would I do to fix that?? >>> >>>Use the fudge to get rid of that offset. nmea is very very slow. And I >>>suspect that you are having the Garmin report a huge number of nmea >>>sentences. That takes along time to parse. >>> >>>And it does not report on the resulting time until the sentences finish. >>>Having just the one standard sentence would reduce that time. >>How would I get that to occur? I don't see a way to cut down on the >>data sent by the unit.... > > >Yousend it an NMEA sentence telling it to not report those sentences you do >not need. > >Setup minicom to listen to the serial port and display the output to your >screen so you can see which sentences are actually being reported. Then >send it the sentences to tell it to switch off the ones you do not need. > >The PGRMO NMEA sentence tells teh garmin to switch off or on the sentence. >EG sending >PGRMO,,2<CR><LF> >(all MUST end with carriage return line feed) will disable all sentences. >That doing >PGRMO,GPRMC,1<CR><LF> >will enable just the GPRMC sentence. > >(The first argument is teh sentence to affect, the second is >0=disable,1=enable, 2=disable all, 3=enable all) > >I found that the easiest way was to construct the sentence in a file, >putting the <CR><LF> at the end of the file, and then cutting and pasting >into the minicom terminal program. OK I set that up to just send the GPRMC data here but it seems to have made little difference in the GPS offset. (left some servers out) ]# ntpq -p remote refid st t when poll reach delay offset jitter ============================================================================== xGPS_NMEA(0) .GPS. 0 l 6 16 377 0.000 -667.14 11.102 *SHM(0) .PPS. 0 l 14 16 377 0.000 4.673 0.908 +eagle-local 192.168.1.2 3 u 43 64 7 0.112 33.566 0.633 +apollo-local 192.168.1.1 3 u 42 64 7 0.248 -4.073 0.729 _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
