Re: [gpsd-dev] A detail in your ntpoffset script

[Dave Platt]

> I see where you are going.  But I have gottent tow PPS to agree to
> better than 1 uSec so I do not think it is a measurement error on
> my part.
> 
> The error is attached to the GPS, not to the port or host I conenct
> it to.  So it is a characteristic of the GPS, not the measurement 
> techniwue.

It would be interesting to measure the electrical offset by a separate
technique which is completely independent of the host interface
timing.

If both GPS systems have explicit PPS outputs, using a dual-trace
digital storage 'scope whose trigger is tied to one of the two
PPS edges would give a very good look at the actual timing.

Won't work with USB-output-only GPS'es, of course.