On Jul 16, 1:56 am, "David J Taylor" <david- tay...@blueyonder.co.uk.invalid> wrote: > > Is there a maximum fudge value above which the NMEA refclock throws > > away input? Both my 18xLVC GPS receivers output serial data about 550 > > ms after the PPS signal. That works fine with gpsd, but I've been > > trying to set up the NMEA driver with pps compiled in the 2.6.34 > > kernel and it doesn't seem to work.I thought I read somewhere that it > > accepts a max of 400 ms but I can't seem to find that anywhere. Could > > anybody tell me what the value is, and maybe point me to the line in > > refclock_nmea.c (if that's where it is) that governs that? > > > Thank you, > > > Court > > Court, > > This site suggests nearer 350ms than 550ms: > > http://www.dangl.at/ausruest/gps18lvc_e.htm > > Are you using the minimum sentences, and the right edge of the PPS signal? > I have no such problems with a GPS18x LVC on Windows with ntpd > 4.2.6p2-RC5-o, but I haven't tried it on FreeBSD which still runs my GPS18 > LVC. > > Cheers, > David
If it was triggering on the wrong edge of the pps signal, wouldn't it be off of the rest of the servers by the length of the pulse? I think that it's triggering properly. remote refid st t when poll reach delay offset jitter ================================================= *SHM(1) .PPS. 0 l 2 16 377 0.000 -0.005 0.005 +SHM(0) .NMEA. 0 l 4 16 377 0.000 12.034 15.490 -dense.utcc.utor 128.100.103.253 2 u 490 512 377 16.047 -0.029 5.304 -ntp-2.gw.illino 128.174.38.133 2 u 844 1024 377 33.467 3.084 1.829 -rs1.tor1.rogers 192.43.244.18 2 u 875 1024 377 19.683 17.259 1.058 +ntp-4.cns.vt.ed 198.82.247.164 2 u 3 64 377 47.869 3.035 3.673 My 555 ms fudge, from the config file. #gpsd PPS server 127.127.28.1 minpoll 4 maxpoll 4 prefer fudge 127.127.28.1 refid PPS #gpsd server 127.127.28.0 minpoll 4 maxpoll 4 fudge 127.127.28.0 refid NMEA flag4 1 time1 0.555 I stopped gpsd to check and make sure I had set the outputs properly, but it shows just one sentence, GPRMC. $GPRMC,130803,A,4416.2422,N,07823.4033,W,000.0,143.4,160710,011.6,W*71 $GPRMC,130804,A,4416.2422,N,07823.4033,W,000.0,143.4,160710,011.6,W*76 $GPRMC,130805,A,4416.2421,N,07823.4033,W,000.0,143.4,160710,011.6,W*74 $GPRMC,130806,A,4416.2421,N,07823.4033,W,000.0,143.4,160710,011.6,W*77 $GPRMC,130807,A,4416.2421,N,07823.4033,W,000.0,143.4,160710,011.6,W*76 $GPRMC,130808,A,4416.2421,N,07823.4033,W,000.0,143.4,160710,011.6,W*79 $GPRMC,130809,A,4416.2421,N,07823.4033,W,000.0,143.4,160710,011.6,W*78 $GPRMC,130810,A,4416.2421,N,07823.4033,W,000.0,143.4,160710,011.6,W*70 $GPRMC,130811,A,4416.2421,N,07823.4033,W,000.0,143.4,160710,011.6,W*71 $GPRMC,130812,A,4416.2421,N,07823.4033,W,000.0,143.4,160710,011.6,W*72 $GPRMC,130813,A,4416.2421,N,07823.4033,W,000.0,143.4,160710,011.6,W*73 _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions