[ntp:questions] Inexpensive OEM GPS units?
Dennis Hilberg, Jr.
timekeeper at dennishilberg.com.invalid
Mon Nov 19 07:30:38 UTC 2007
Chris Adams wrote:
> Once upon a time, Steve Kostecke <kostecke at ntp.org> said:
>> What does ntpq -p show?
>
> $ ntpq -p
> remote refid st t when poll reach delay offset jitter
> ==============================================================================
> -fly.hiwaay.net 192.5.41.40 2 u 2 64 377 16.351 9.846 1.449
> +lashiir.sapros. 74.53.198.146 3 u 36 64 377 48.593 6.778 0.636
> +newton.8086.net 209.51.161.238 2 u 39 64 377 27.075 5.322 0.970
> -ntp.unknowndevi 18.26.4.105 2 u 52 64 377 51.295 -9.173 6.805
> LOCAL(0) .LOCL. 10 l 52 64 377 0.000 0.000 0.002
> xGPS_NMEA(0) .GPS. 0 l 11 64 377 0.000 143.198 56.164
> *SHM(0) .SHM. 0 l 2 16 377 0.000 -0.195 0.541
> $
>
> The PPS is run via shm_splc2, so the GPS_NMEA is guaranteed to be off
> (but it gets the date/time info). This is using pool servers plus an
> ISP server (across a DSL link from my box).
I run a Garmin GPS 18 LVC over serial, and get the PPS signal via the shmpps
(shm_splc2) driver. Here is my 'ntpq -p' and 'ntpq -crv':
saturn:$ ntpq -p
remote refid st t when poll reach delay offset jitter
==============================================================================
*SHM(0) .PPS. 0 l 13 16 377 0.000 0.000 0.001
-bigben.cac.wash .USNO. 1 u 26 64 377 13.568 -1.107 2.694
-clepsydra.dec.c .GPS. 1 u 37 64 377 32.296 -1.607 3.923
-time.sdsc.edu .WWVB. 1 u 4 64 377 41.676 -4.008 2.228
-clock.sjc.he.ne .CDMA. 1 u 5 64 377 33.254 -1.262 1.950
+tick.ucla.edu .GPS. 1 u 48 64 377 42.264 -0.820 6.585
+clock.xmission. .GPS. 1 u 4 64 377 51.862 -0.540 1.430
saturn:$ ntpq -crv
assID=0 status=0964 leap_none, sync_telephone, 6 events, event_peer/strat_chg,
version="ntpd 4.2.4p4 at 1.1520 Sun Oct 7 00:42:35 UTC 2007 (2)",
processor="i686", system="Linux/2.6.17-5mdv", leap=00, stratum=1,
precision=-20, rootdelay=0.000, rootdispersion=0.243, peer=28353,
refid=PPS, reftime=caebb9b5.a65ccee4 Sun, Nov 18 2007 23:28:53.649,
poll=4, clock=caebb9b6.5599d760 Sun, Nov 18 2007 23:28:54.334, state=4,
offset=0.000, frequency=-22.465, jitter=0.001, noise=0.001,
stability=0.000
--
Dennis Hilberg, Jr. timekeeper(at)dennishilberg(dot)com
NTP Server Information: http://saturn.dennishilberg.com/ntp.php
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