View Single Post
  #11  
Old November 1st 11, 11:21 PM posted to sci.geo.satellite-nav,rec.aviation.ifr
Alan Browne
external usenet poster
 
Posts: 18
Default PRN133 ranging now useable for SoL, at non precision approachlevel

On 2011-11-01 17:47 , HIPAR wrote:
On Nov 1, 9:25 am, Alan
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.


That wouldn't fly far - there are only so many viable gold codes -
though possibly many more on L5 with its longer code length.

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.


No idea. But with the network of ground stations collecting the data
for GDGPS that data can be "sold" to J-D for further use. In that sense
JD depend on the network, but they package the data for Starfire (and to
finer resolution and accuracy than WAAS).

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.


But EGNOS provides SBAS for both GPS and GLONASS...

--
gmail originated posts filtered due to spam.