[time-nuts] GPS orthodontics: sawteeth & hanging bridges

[Poul-Henning Kamp]

In message <458B03AA.4000209 at xtra.co.nz>, Dr Bruce Griffiths writes:

>If only one had access to the receiver firmware: the cure for "hanging 
>bridges" etc is surely to add sufficient (rms noise ~ PPS positioning 
>quantisation error) bandlimited gaussian noise to calculated PPS 
>position before quantisation of the PPS position occurs in the hardware.

The negative saw-tooth field _is_ the cure.

As long as you apply the correction, you are in pretty amazing shape.

The trouble is when you do not apply the correction.

Curing that would take more involved hardware than the oncore has,
so firmware access would not help you.

The more involved hardware is what the CNS Clock is all about as far
as I can tell.

If you feed a PRS10, and it's firmware is new enough, you just need
to read the serial data from the oncore, and send the correction
to the PRS10 and everybody are happy.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
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