Thanks Bruce for your input. It seems to have quieted the crowd.
You wrote (and it's worth repeating!!)
"This debate grows more interesting with time.
Current publicly available Galileo documentation indicates that "Safety of Life" services will be provided on E5a/E5b (1164 to 1215 MHz) downlink and the E2/L1/E1 (1559 to 1591 MHz) downlink. The E6 (1260 to 1300 MHz) downlink is designated for 'commercial services' and not the aviation. Thus, I am VERY curious why the interference to aircraft navigation receivers is constantly brought up in this discussion as it appears a non-player.
For all but the most precise needs, dual frequency capabilities will eliminate the 1st order ionospheric errors leaving only the 2nd and 3rd order terms which are on the centimeter level. Thus I don't see the need for aircraft navigation systems to employ 'tri-frequency' receivers.
What am I missing here?