On Sun, Apr 27, 2014 at 2:14 AM, Poul-Henning Kamp <p...@phk.freebsd.dk>wrote > > Position Hold is what makes a GPS receiver "timing", the sawtooth > correction > 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" _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.