[time-nuts] GPS 1PPS ultimate accuracy
erm1eaae7 at ermione.com
Thu Jan 15 05:11:53 EST 2015
On Mon, Jan 12, 2015 at 03:10:39PM +0100, Attila Kinali wrote:
> The GNSS Timing AppNote for the LEA6-T receiver will give you an idea
> what jitter you get with GPS. Please be aware that these measurements
> were done with an antenna located at a _good_ position (ontop of a 4 story
> building with no other high buildings around). Unless you have a simlarly
> good location you will have worse performance.
By the way, I see there are LEA-6T from Hong Kong at 49 USD shipping included.
If those are not a fake and I can extract the PPS from them, do you suggest
this as the best GPS for the price actually available for timing?
> It would average out if and only if the sawtooth correction would be completely
> independent of anything else. But it isn't. This results in effects where the
> cycle to cycle jitter is quite low, but there is a large offset in the sawtooth
> correction. This is know as "hanging bridges" in the GNSS world.
I can use the sawtooth correction with LEA-6T but if I am using it with a
normal TIC I should obtain a way either to apply the correction in hardware,
or to capture the numbers and postprocess them together with data from the TIC.
Probably the simple solution is a GPSDO where everything is already done?
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