[time-nuts] Speaking of Costas loops

[Attila Kinali]

On Tue, 2 Jul 2013 17:06:47 -0400
<jmfranke at cox.net> wrote:

> Valid concerns all. What I am building is a squaring circuit for
> recovering the carrier from a WAAS GPS satellite. Granted there
> is still some Doppler and other issues, but the accuracy would not
> be bad and it just looks like a fun thing to do. Plus, I can use my
> four foot diameter dish antenna to reduce the number of satellites seen,
> reduce thermal ground noise, and get some signal gain.

Right.. i didnt think about the WAAS/EGNOS satelites.
If i'm not mistaken, then you dont have to correct for doppler, as
the satelites are stationary relative to you. The only thing you might
want to correct for are atmospheric changes, but if you are tracking
frequency only, and don't care about the phase relation, respektively
can live with some phase noise, then you dont even need to do that.

Correcting for atmospheric changes should be "fairly" simple. You just
need to decode the WAAS/EGNOS signal, read the atmosphere/TEC data out
and apply a phase shift according to that.

			Attila Kinali

-- 
The trouble with you, Shev, is you don't say anything until you've saved
up a whole truckload of damned heavy brick arguments and then you dump
them all out and never look at the bleeding body mangled beneath the heap
		-- Tirin, The Dispossessed, U. Le Guin