[ntp:questions] PPS and NMEA

Rob van der Putten rob at sput.nl
Mon Sep 10 09:02:37 UTC 2012


Hi there


ksprabha wrote:

> Kindly let me know what is the difference between NTP with PPS and NTP with out PPS.

NMEA can be a bit off with some GPS receivers. PPS tends to be very 
accurate.

When using RS232, NMEA is send via a data line. PPS via the DCD status line.

A few graphs;
http://www.sput.nl/ntpstats/parents/

Using the following setup;
NMEA and PPS;
http://www.sput.nl/time/garmin.html
DCF77 [1];
http://www.sput.nl/time/dcf77.html

With these receivers DCF77 so more accurate then NMEA. PSS is more 
accurate then DCF77

[1] http://en.wikipedia.org/wiki/DCF77


Regards,
Rob
-- 
The end is near;
http://www.ripe.net/internet-coordination/ipv4-exhaustion/ipv4-available-pool-graph



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