[ntp:questions] Garmin GPS 18LVC Setup but questions on best way

Chris givemeafckingacctyoudouche at gmail.com
Fri Jan 2 01:17:47 UTC 2009


On Jan 1, 12:38 pm, Evandro Menezes <evan... at mailinator.com> wrote:
> On Dec 31 2008, 8:49 pm, givemeafckingacctyoudou... at gmail.com wrote:
>
>
>
> > So, basically I'm manually adjusting the nmea second reading forward
> > by 1.
>
> > The SHM(0) gps is still fudged to account for normal lag w/ the time
> > given on qnan. Here's my conf with the modified gpsd:
> > #Garmin GPS 18x LVC 0
> > server 127.127.28.0 minpoll 4 noselect  #Local GPS serial
> > fudge 127.127.28.0 time1 -0.420 refid GPSa
>
> How is this different from leaving the source code intact and fudging
> the reference by +0.580?
>
> TIA

Sorry for the double post, but it's easier to prove via logs too.
ntpd.conf:

#Garmin GPS 18x LVC 0.520 worked tried up to 0.800
server 127.127.28.0 minpoll 4 noselect  #Local GPS serial
#fudge 127.127.28.0 time1 -0.420 refid GPSa
#to prove positive adjustment doesn't work
fudge 127.127.28.0 time1 0.580 refid GPSa
#PPS pin
server 127.127.28.1 minpoll 4 prefer
fudge 127.127.28.1 refid PPSa

ntpq -p response:
==============================================================================
 SHM(0)          .GPSa.           0 l   13   16   77    0.000
-79.107  20.795
 SHM(1)          .PPSa.           0 l    -   16    0    0.000
0.000   0.001
 navobs1.gatech. .GPS.            1 u   32   64    3   62.163
3.120   0.211
 ntp-s1.cise.ufl .GPS.            1 u   28   64    3   67.988
1.296  18.917

See, no PPS output but SHM(0) is about on target.

and gpsd (non-modified version) output log
--SNIP--
gpsd: pps-detect (DCD) on /dev/ttyS0 changed to 1
gpsd: ntpshm_pps: not in locking range: 627236
gpsd: PPS pulse. cycle: 1000006, duration: 799999
gpsd: pps-detect (DCD) on /dev/ttyS0 changed to 0
gpsd: ntpshm_pps: not in locking range: 627236
gpsd: PPS pulse. cycle: 999988, duration: 199989
--SNIP--




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