[time-nuts] Accuracy/drift of Garmin GPS 16 HVS 1 PPS output under invalid fix conditions...

[Bob kb8tq]

Hi

Sorry if this is an ongoing / somewhat random dump of a bunch of things … I am not doing the 
same sort of thing you are doing. That makes a lot of this a bit less focused than maybe 
it could be.

One thing that might “help” Windows stay on time would be to set up NTP on the machine. 
Feed it with the GPS PPS and the concerns about staying within 30 seconds of the right time. 
NTP *should* be able to get the machine into the “low ms” sort of range. You will still have 
issues generating an output with millisecond resolution. Windows simply is not designed
to be a real time operating system. 

Again, just trying to help out. There are *lots* of ways this could go. I very much do not
understand the sort of post processing you are doing so much of this could be absolute
nonsense when applied to your problem … What you are trying to do is not at all easy
so there *are* a lot of constraints that I’m not aware of …. sorry about that :)

Bob



> On Mar 11, 2019, at 9:54 PM, Steve Olney <t0502 at internode.on.net> wrote:
> 
> Hi Bob,
> 
> On 12/03/2019 9:04 am, Bob kb8tq wrote:
>> A “proper” timing device with antenna is a sub $100 sort of thing. It will be < 100 ns pretty much forever and ever.
> 
> Yes - understood.  The system I am building needs to generate a gate on a known zero-second boundary.   At the moment I am working on a three-tier system...
> 
> 1. Windows PC providing a gate about one minute duration (+/- 30
>   seconds around the required zero-second).  Hopefully Windows can
>   manage that...
> 2. Microcontroller identifying the zero-second within that minute and
>   providing a gate +/- 500 ms around the zero-second.
> 3. And-ing the 1 PPS signal with this gate to clock the final output
>   gate opening.
> 
> Cheers
> 
> Steve
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com
> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.