[ntp:questions] How exact are the PPS pulses of common GPSses?

Ralph Aichinger ralph at pangea.at
Wed Feb 13 09:00:15 UTC 2013


After having my Raspberry Pi with PPS running, with an
offset and jitter value in the region of 1 to 5 microseconds,
I am wondering: How precise is the PPS signal of typical
consumer hardware (MTK chips, etc.)?

Has anybody hooked up the PPS output of different consumer
GPSes to an oscilloscope and compared it against eachother  
with a precision clock?

Is the precision of the PPS pulse higher than what
the computer/ntpd daemon can usefully handle, or is
the PPS pulse the limiting factor?

/ralph



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