James, the Garmin unit does not include a GPS.
Airservices imply that you just run a wire to a certified GPS and everything is approved.
This is not so.
If ADSB is so simple and proven and risk free why are Airservices spending millions of dollars of our industries money on a totally different system in Tasmania?
It's called "Multilateration" and works with standard transponders and keeps working if the GPS system has a fault.
Try and get that question answered!
More importantly' Airservices are having problems with the high level ADSB system with delays and cost overuns.
They can't even get the data transfer between the ADSB transceivers going without problems and I understand in mid-stream they have been forced to change contractors.
A similar situation occurred with the Seasprite contract before the Government stepped in and cancelled the project.
Their ADSB plan is totally based on the financial saving made by the early removal of the existing SSR units -and thats where the risk is. By not entering a contract now to refurbish or replace the radars(which is their stated plan) they have all their eggs in one basket. If the ADSB contract does not go as planned we are completely stuffed in Australia.