Old Akro,
Thanks for the links to that further information. I haven't delved into it yet, but am really curious about one particular aspect of this issue:
The requirement that the ADSB transmitted position be the same as the position used by the onboard navigation system.
I am curious because this one requirement has made the installation requirements much more complicated - and therefore, much more expensive. I heard that, for a chap with a Global 5000 jet, the avionics upgrade cost him about $130,000.
This requirement would be acceptable if there was some tangible benefit behind it, but I cannot see any. I would really like to know what the supposed advantage/benefit is.
I can only see a disadvantage, which is because there could have been two (2) independent positions in play, but now there is only one.
With two positions, it would have been more obvious if a significant discrepancy between positions had arisen. With only one, that discrepancy could remain hidden.
I know this is not a big concern, given the expected accuracy and consistency of the positions, but in the absence of any other reasons, it really stands out.
It would have been a much more robust system with the two positions in play. I think we all take the availability and accuracy of GNSS positions for granted these days, but a future event involving solar flares (taking out some of the satellites) could make things interesting.