[time-nuts] GPS message jitter (was GPS for Nixie Clock)
David J Taylor
david-taylor at blueyonder.co.uk
Sun Jul 17 02:31:13 EDT 2016
From: Mark Sims
I just added some code to Lady Heather to record and plot the time that the
timing message arrived from the receiver (well, actually the time that the
screen update routine was called, maybe a few microseconds difference).
I am using my existing GetMsec() routine which on Windoze actually has
around a 16 msec granularity. The Linux version uses the Linux nanosecond
clock (divided down to msec resolution). I just started testing it on a
Ublox 8M in NMEA and binary message mode... really surprising results to
Thanks for those updates.
For Windows lower than 8, turn on the high-resolution timer and you can get
millisecond level (0.977 ms IIRC). You can also use the
QueryPeformanceCounter and related functions for better precision.
However for current Windows (8, 8.1 10) the situation is much better as you
can get 100 ns precision using the new GetSystemTimePreciseAsFileTime call:
I wrote up a little more here:
I look forward to your results.
SatSignal Software - Quality software written to your requirements
Email: david-taylor at blueyonder.co.uk
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