Shedding some light
A few comments on this thread- hope it helps those who are interested in this subject:
The technology
1. ADS-B (over 1090 Extended Squitter) will give you the same set of data as Mode S Enhanced Surveillance (this version of Mode S having a mandate in UK, France and Germany). It is from the same on-board data register. The difference comes in position determination - ADS-B uses aircraft positioning sources, Mode S uses azimuth and signal ranging from the ground.
2. The SBS-1 unit from Kinetic will not interrogate aircraft. It is merely a receiver. However, within this limit, it can receive whatever data is sent by the aircraft. This may be Mode S information (no position!) or ADS-B 1090ES information (with position). So technically, they can talk about Mode S reception - it's just that (to my mind) it can't be used by them for anything.
3. Another technology which uses the 'opportunity' signals from Mode S (and anything else on the 1090MHz frequency) is multilateration. This is what Innsbruck have implemented successfully, ostensibly as a support to RNP 0.3 operations.
4. The Dependent nature of ADS-B is indeed an issue (i.e. dependent on where the aircraft thinks it is). Not so much from an accuracy point of view - the figures can be astounding. The main issue (amongst others!) comes from the integrity of GPS, as it currently stands. GLONASS is not operational - only 11 of the necessary 18 satellites are up there. India may launch 3 more GLONASS sats to kick-start its own space programme, but that still leaves us 4 short. How will this therefore be solved? Initially, ADS-B will only be used in low density areas, where procedural control is a viable back-up. Another mitigation is using independent position validation via multilateration (triangulating the aircraft signals to obtain a position estimate).
As we get WAAS, EGNOS, GPS Phase 2, Galileo, MTSAT, China's SBAS etc, I believe the integrity will reach levels we can accept for safety-of-life services such as aviation.
All this is assuming the ADS-B position is purely coming from GNSS... actually, it is likely to become an FMS output, and will be compatible with the airspace requirements (e.g. using DME/DME, INS/IRS etc).
5. For security reasons (and safety mitigation reasons), I don't believe ADS-B will ever replace Primary Radar. Not least because the military own a load of systems and will keep them for air defence purposes.
The implementation plans
Fact: Mode S SSRs are expensive. Multilateration (MLAT) and ADS-B ground stations - often combined - are cheaper. And easier to maintain. And can extract potentially more information at a higher update rate with greater accuracies.
Australia has purchased 1090MHz ADS-B ground stations, and will carry out radar-like en-route services using ADS_B sole means surveillance. Indeed, ICAO, Eurocontrol, the FAA and Airservices Australia have almost agreed on a safety and performance case for ADS-B (comparative to radar), such that it can be used in place of radar.
As TACAN mentions, the USA is currently considering a potential mandate for ADS-B operations, so that they can reduce their infrastructure. This is because they MUST become cost-effective. It isn't an option any more. Under the plans going to FAA top-brass (and congress), as radars require replacing (over time), they would be rationalised and phased out in place of ADS-B.
Europe is starting to consider a similar route. Again, cost pressures (cost transparency) for the ANSPs is the main issue. A secondary issue is the potential to have Gate-to-Gate surveillance (a surveillance layer covering a Single European Sky!). Wide Area Multilateration with ADS-B data is the possible future direction for surveillance.
Iron City: investment analysis fairy tales? - maybe? But I believe in the next 10 years, that frog will have turned into a prince.