[ntp:questions] How to debug PPS?

Terje Mathisen "terje.mathisen at tmsw.no" at ntp.org
Wed May 5 20:03:21 UTC 2010

David J Taylor wrote:
> "Mr Dave Baxter" <g8kbv at uko2.co.uk> wrote in message
> []
>> Indeed, but is GPGGA the correct sentence for NTPD to use? Mine is set
>> for GPRMC & works just fine.
>> pip pip
>> Dave B.
> It depends on the NTP version, Dave. I believe that newer versions allow
> more sentences. Like you, I've used the originally recommended $GPRMC.
> It's important not to use too many sentences otherwise they can't all
> fit into the available time at 4800 baud - I recommend using a single
> $GPRMC sentence type.

GPGGA has one added benefit: If you turn on clockstats you get a log of 
the current position every second, this is perfect input for a 
statistical averaging of the current antenna position. :-)

Afair you also get quite a bit of position/time quality information, in 
the number of currently tracked sats and the current DOP value.

Otherwise they are pretty much equivalent.


- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"

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