For some reason the copy of this message I received via [email protected] was truncated after the Terje quote, conveniently omitting everything I said. In Google's Group's usenet web interface, the complete message is displayed.
So, once more with feeling, and without any correction like removing the duplicate signature... ---------- Forwarded message ---------- From: Dave Hart <[email protected]> Date: Feb 7, 16:40 UTC Subject: fudge time1 for gps-18x-LVC? To: comp.protocols.time.ntp On Feb 7, 14:59 UTC, Terje Mathisen wrote: > David J Taylor wrote: > > Indeed, but I think we've talked about this before with David and > > "default" may mean "default for use with NTP". We'll see. Certainly the > > single sentence is the best - I happen to use: $GPRMC. > I'm trying to make $GPGGA the default, it is a much more informative > sentence (using 'mode 2' in the server statement specifies this): > It contains the current time (hms), position (ddmm.mmmm), nr of visible > sats, DOP etc, which makes it easy to write a little perl script to > process the clockstats file to gather all sorts of interesting statistics. Historically, the NMEA driver claimed to use any/all sentences in the default (mode 0) configuration, but it lied and in fact treated mode 0 the same as mode 1, which is to say it ignored all but $GPRMC. This was fixed during the period 4.2.5 was ntp-dev, and with the current code, you really can use any/all of the supported sentences by configuring mode 0. That allows you to choose which sentence to use without touching ntp.conf, by reconfiguring the NMEA device to send a single sentence of your choosing. I don't know about you, but looking up modes on the NMEA driver's driver22.html and configuring them is tedious to me -- I'd much rather fire up the Garmin configuration software and switch sentences that way. Moreover, using mode 0, there is need to match changes to the device configuration with changes to the mode number. You can see which is being used easily enough: ntpq -ccv If you have more than one reference clock driver configured, you can select which using the longer form: ntpq -p -c "cv &1" &1 is equivalent to the first association ID and must come after a command which lists the associations such as -p / peer or assoc. The cv (clockvar) output looks like: associd=35286 status=0011 , 1 event, clk_no_reply, device="NMEA GPS Clock", timecode="$GPGLL,____.____,N,_____.____,W,163332,A*__", poll=27796, noreply=1, badformat=0, baddata=0, fudgetime1=-6.729, stratum=0, refid=uPPS, flags=8 (that's with fudge flag4 1 set to obscure the location.) So to be clear, the NMEA driver no longer has any preference for $GPRMC in 4.2.6 and later. With mode 0, every recognized sentence is processed, with the effect that the last recognized one seen is the one used. Cheers, Dave Hart Cheers, Dave Hart _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
