[time-nuts] GPS backup for the stationary time and frequencyuser
Magnus Danielson
magnus at rubidium.dyndns.org
Sat Oct 9 12:30:58 UTC 2010
On 10/08/2010 08:09 PM, Brooke Clarke wrote:
> Hi John:
>
> The WAAS birds may be too weak to receive with an omni antenna, hence
> the desire to get some gain.
> The normal GPS sats will pass through the beam and the GPS antenna will
> pick up some sats directly so you do get some TRAIM.
> Doppler is not an issue in timing mode (i.e. position is known) and only
> one sat is required.
The WAAS/EGNOS/SBAS power should be equal to the GPS birds, such that a
normal GPS receiver can receive them on the same antenna, the code is
such that a standard GPS receiver channel can lock to it, the big
difference lies in the rate and encoding of the data-channel. Calls for
some extra software including a standard Viterbi-decoder.
Cheers,
Magnus
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