Re: [gpsd-users] Garmin 18X-5Hz

[Robin Schwab]

Am 12.08.2016 um 20:37 schrieb Gary E. Miller:
> On thing that is coming to light, ntpd tends to chase quantization errors
> rather than averge them out.  No solutions yet.
>
> For exammple:  https://pi3.rellim.com/day/

Hello Gary
Your graphs are by characteristic very similar to what I got with a 
raspberrypi 2 and the adafruit GPS. I got much better on an absolute 
scale but the sawtooth-like waveform remains. Strange thing: It can 
happen that the periodic error disappears but it's unclear to me under 
which circumstances. Without the periodic error I could stretch the 
graph to -+10 us which is imo pretty good for a 100$ hardware setup.

Big advantage of the adafruit: You can set NEMA update rate and UART 
baud rate separately.

Regards

Robin