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Old November 1st 11, 09:47 PM posted to sci.geo.satellite-nav,rec.aviation.ifr
HIPAR
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Posts: 6
Default PRN133 ranging now useable for SoL, at non precision approach level

On Nov 1, 9:25*am, Alan Browne
wrote:

....

L5 isn't exactly usable yet with all of 2 sats in orbit. *Will be a long
wait before any advance with any system. *For simplicity sake (a good
thing in avionics) mixing GPS with EGNOS in a system won't be seen in
avionics for quite a while yet.

--


I couldn't agree more that we need simplicity .. too many
constellations transmitting signals that are compatible only by the
definition of not interfering with each other. My head would be
spinning if I were tasked to perform a trade study defining the next
generation of avionics. But the GNSS community thinks this kind of
diversity is great so those geniuses like Marcelo (just joking) can
sort it out.

Would it have been nice if Galileo L5 and NAVSTAR L5 shared a common
ICD? Would it have been nice if there were a common L1 modernized
signal. That would be 'bound' the problem.

Regarding WDGPS, I really don't understand who actually controls
access to the system. If NASA operates the core system, what kind of
agreement does the US government have with Deere allowing them
exclusive commercial marketing rights under the Starfire trademark?
NASA/JPL doesn't say much about that.

I looked over a few of the easier to read references concerning the
JPL system. This one addresses the expected performance for a GDGPS
corrected C/A code system:

http://www.gdgps.net/system-desc/pap...leFreqCorr.pdf

Receiving L1 only, I'd say it might provide WAAS grade performance.
Getting back to simplicity, the need to receive the corrections from
another satellite system would complicate the actual operations.
Along with the other issues discussed, WAAS remains a more practical
system for airplanes.

--- CHAS





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