Folks,
A point I have made elsewhere, there are three(3), ICAO ADS-B standards.
So far unmentioned (unmentionable ??) is VDL-4. As far as I have been able to determine, VDL-4 is the only one of the three in daily used for actual ATC purposes at present, right now, at this time, as we speak --- as opposed to "trials", and that daily use is in Scandinavia. The "Mediterranean" trial is also VDL-4.
Most of the US trials, including all the work in Alaska, and all the United Parcel Service demonstrations of pilot managed approach sequencing, have been UAT. Right now, a big FAA UAT installation program is under way, it is going in across a number of the US eastern seaboard states. The whole value of the Alaska Capstone program was about the advantages of C145/146 GPS, moving maps and a broadband datalink, aircraft to aircraft "collision avoidance" was a relatively minor issue/bonus.
Most of the Northern European/CIS states have announced the adoption of VDL-4, whether it will happen is another thing altogether. How does that fit with Eurocontrol/ECAC ??--- it will keep an army of bureaucrats happy spending our ATC fees and large volumes of taxpayer's cubic Euros on busywork for years --- just like Galileo, really.
VDL-4 seems to be the market leader for on-airport ground collision avoidance, including the US, interestingly VDL-4 has been adopted by the US Marines as standard for its practice ranges, for tracking.
The good thing about ES1090 --- it's just an addition to a TXPD Mode S signal.
As all the Australian propaganda said/says, just a simple connection from a GPS (or FMCS) to a Mode S transponder --- remember the Airservices brochure for airlines, that showed a piece of wire and a 1.44 floppy for the software.
The bad thing about ES1090 --- it's just an addition to a TXPD Mode S signal.
With all the limitations of very restricted band width compared to UAT (~WBCDMA) and VDL-4 (more or less GSM 2.5), and only 4096 channels for the basic Mode A signal ---and --- (ask QF)--- the cheap, quick and easy retrofitting for airlines "ain't necessarily so".
Indeed hardly ever, unless the 747/744/767/757/737/add long DC/MD list was ES1090 capable ex-factory. Early (less than the last several years delivery) Airbus, I don't know, but I rather suspect the same, retrofitting ES1090 is very expensive (complete recertification of a new FMCS/ADC fit) and hard to justify in an older aircraft -- and that just for ADS-B "out". Integrating ADS-B "in" with TCAS 11 is a whole new ballgame, again unless it was delivered ex-factory ---- Unless the aircraft are really old, where all the avionics are separate boxes, like most GA aircraft, just update the boxes, a bucket of $$$ for the STC, $0.25M for a 100/200/300 B747 or other "707 vintage" stuff.
ES1090 will never cut it for ground collision avoidance as is being proposed.
As for Raytheon's proposal to dump UAT ---- Mitre Corp. (FAA) will probably have something to say about that, because of the "The bad thing --" above, particularly the 4096 limitation. Given the number of aircraft in US (and airport vehicles) it wouldn't be too hard to see more than 4096 transceivers in line of sight.
Tootle pip!!