[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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