[time-nuts] New timing receivers?
tic-toc at bodosom.net
Sun Apr 27 23:45:31 EDT 2014
On Sun, Apr 27, 2014 at 2:14 AM, Poul-Henning Kamp <phk at phk.freebsd.dk>wrote
> Position Hold is what makes a GPS receiver "timing", the sawtooth
> is icing on the cake.
I've been curious about this for a while:
SkyNav says the SKG16 (based on the MT3329) has a timing accuracy of 60ns
rms. Sure says 20ns. TVB measured 20ns with 60ns p-p sawtooth.
GlobalTop says the FGPMMOPA6H (based on the MT3339) used in the previously
mentioned AdaFruit break-out has a PPS with 10ns jitter(?).
u-blox says 30ns or 15ns with sawtooth correction. In the 2011 edition of
Tom&Rick (the slide has gone missing in the 2013 edition*) they show the
LEA-6T at 20ns uncorrected and ~5ns corrected.
Trimble says <15ns rms for the SMT.
So I wonder if the MTK units are doing fixed position timing, if these
numbers have not relationship to each other or if it's not that important.
*btw, that's where they say "Even if (/when?) the Motorola/iLotus M12’s
become unavailable, the uBlox LEA6T can step in as a replacement"
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