George R. Kasica wrote: > On Mon, 29 Dec 2008 09:45:51 -0500, "Richard B. Gilbert" > <[email protected]> wrote: > >> George R. Kasica wrote: >>>>> Since you have a GPS receiver, three internet servers should be >>>>> sufficient as backup and a sanity check for the GPS. >>>> See below, now set up as recommended with three us.pool.ntp.org >>>> servers but as you say it will take some time to be useful, but I >>>> don't seem to be getting the NEMA data as of 1415Z 28-dec-2008. >>>> >>>> # ntpq -p >>>> remote refid st t when poll reach delay offset >>>> jitter >>>> ============================================================================== >>>> GPS_NMEA(0) .GPS. 0 l 273 16 0 0.000 -664.93 >>>> 0.002 >>>> xSHM(0) .PPS. 0 l 7 16 227 0.000 -634.51 >>>> 349.893 >>>> eagle-local 192.168.1.7 4 u 11 64 37 0.120 -11.083 >>>> 0.523 >>>> apollo-local 192.168.1.7 3 u 18 64 37 0.224 6.685 >>>> 0.765 >>>> x64.247.17.251 129.6.15.28 2 u 12 64 37 34.158 -18.850 >>>> 6.764 >>>> +ip-72-167-54-20 204.123.2.72 2 u 13 64 37 82.722 1.031 >>>> 1.821 >>>> *caspak.cerias.p .GPS. 1 u 10 64 37 22.867 7.745 >>>> 10.934 >>>> >>> OK here is about 21 hours later 11Z 29 Dec-2008: >>> >>> # ntpq -p >>> remote refid st t when poll reach delay offset >>> jitter >>> ============================================================================== >>> xGPS_NMEA(0) .GPS. 0 l 2 16 375 0.000 -722.08 >>> 9.115 >>> xSHM(0) .PPS. 0 l 6 16 377 0.000 -722.20 >>> 7.892 >>> eagle-local 192.168.1.7 4 u 390 1024 377 0.181 -5.629 >>> 4.389 >>> apollo-local 192.168.1.7 4 u 410 1024 377 0.311 -2.394 >>> 0.299 >>> *got.my.mojo.net 192.5.41.41 2 u 966 1024 377 30.157 -5.166 >>> 0.361 >>> +kiri.nonexiste. 64.202.112.75 2 u 644 1024 377 9.423 -5.517 >>> 203.143 >>> +host2.kingrst.c 99.150.184.201 2 u 944 1024 377 16.221 -11.608 >>> 16.695 >>> >>> >>> still seing both of the local GPS/PPS entries as false tickers but I >>> also see the offsets are huge compared to other clocks...where do I go >>> from here to correct this?? >>> >>> ntp.conf is below: >>> >>> # LinuxPPS: GPS >>> server 127.127.20.0 minpoll 4 >>> fudge 127.127.20.0 flag3 1 flag2 0 >>> >>> # SHM: PPS filtered mean >>> server 127.127.28.0 minpoll 4 >>> fudge 127.127.28.0 refid PPS flag3 1 >>> >>> server eagle.netwrx1.com iburst >>> server apollo.netwrx1.com iburst >>> server 0.us.pool.ntp.org iburst >>> server 1.us.pool.ntp.org iburst >>> server 2.us.pool.ntp.org iburst >> Without actually being there it's difficult to say. Clearly something >> is very wrong but exactly what is not immediately obvious, at least to >> me! Your GPS receiver is being rejected as a falseticker! > So what do I need to do here? It was working well with just shm and > the PPS signal, once I added both NEMA and PPS things went > south....what do I need to be looking at here, I'm by far not an > expert at this. > >> I can't say it's because it's presenting an in correct time; that's most >> unlikely assuming it's installed correctly and can see at least four >> satellites. > When I look at the GPS unit with the Garmin utility in Windows it has > a fix and altitude in it so I'm assuming its seeing a sufficient > number and also gpsd is griping about too many satellites at times in > /var/log/messages so I'm guessing there are far more than 4.
Last I heard there were some 27 GPS satellites aloft! There are usually seven or eight above the horizon though some may not be very far above the horizon. Your GPS should select four of the available satellites and use their signals to compute a 4-D fix, latitude, longitude, elevation and time. I know the Garmin GPS18LVC only by reputation. I'm using a a Motorola receiver whose model designation I have forgotten. I think your best help/advice will come from another GPS18LVC user. _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
