[ntp:questions] How to debug GPS PPS?

unruh unruh at wormhole.physics.ubc.ca
Mon Dec 21 19:36:08 UTC 2009


On 2009-12-21, xyz-2041 <xyz2041 at gmail.com> wrote:
> ntpq> pe  GPS line reads:
>
>  GPS_NMEA(1)     .GPS.            0 l    -   64    0    0.000
> 0.000   0.001
>
>
> ntpq> rv
> assID=0 status=06f4 leap_none, sync_ntp, 15 events, event_peer/
> strat_chg,
> version="ntpd 4.2.4p7 at 1.1607-o Wed Dec 16 07:24:35 UTC 2009 (1)",
> processor="i386", system="FreeBSD/7.2-RELEASE", leap=00, stratum=2,
> precision=-20, rootdelay=53.694, rootdispersion=31.936, peer=3269,
> refid=18.26.4.105,
> reftime=ceda45a9.1bda1b54  Mon, Dec 21 2009 13:06:17.108, poll=8,
> clock=ceda4a7b.9a36d363  Mon, Dec 21 2009 13:26:51.602, state=4,
> offset=-3.784, frequency=-47.665, jitter=2.066, noise=3.569,
> stability=0.026, tai=0

Is the gps plugged into the serial port? Is the PPS line operating ( eg
does it have an led on it to let you know that it is working)? And
serial interrupts turned on? 

>
>
>
> # ntptime
> ntp_gettime() returns code 0 (OK)
>   time ceda48c0.01611ba4  Mon, Dec 21 2009 13:19:28.005, (.005388419),
>   maximum error 445680 us, estimated error 3569 us, TAI offset 0
> ntp_adjtime() returns code 0 (OK)
>   modes 0x0 (),
>   offset -3119.252 us, frequency -47.665 ppm, interval 4 s,
>   maximum error 445680 us, estimated error 3569 us,
>   status 0x2001 (PLL,NANO),
>   time constant 8, precision 0.001 us, tolerance 496 ppm,
>   pps frequency -47.445 ppm, stability 0.000 ppm, jitter 0.000 us,
>   intervals 0, jitter exceeded 0, stability exceeded 0, errors 0.
>
> What to check next?




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