[time-nuts] tube GPS receivers

[Magnus Danielson]

On 06/23/2013 12:04 AM, Jim Lux wrote:
> I think that doing the PN code and correlator is something that could be
> done with tubes (especially if you didn't want to go P-code).
>
> I suppose you could use a counter to record the changes in code phase as
> you scan for the correlation peak, so that gets you your numeric code
> phase.
>
> Getting doppler as a number for computation might be tricky, but you
> could probably solve for the position and clock offset without using
> doppler.
>
> Decoding the nav message at 50bps should be straight forward.

All that is relatively trivial... compared to

> Hmm. what about implementing the nav calculation as an analog computer.
> ANalog multipliers were built using vacuum tubes.

You will need more ummpf to do the trigonometry. If you go 
electromechanical you can do it, but it will be rough estimation 
regardless. CORDIC was made for these circumstances, to let a weak 
processing mechanism do navigation processing for airplanes. You could 
do CORDIC in tubes or relays. Bunch of transistors and diodes could make 
minor wonders in compactness.

Cheers,
Magnus