Ian Strachan wrote:

As I understand it, ADS-B (Automatic Dependent Surveillance-Broadcast)
is a system based on Satellite Navigation that automatically transmits
GPS (or GLONASS or Galileo) position and other data from an aircraft to
other receivers in ATC units and/or other aircraft. It is being tested
by the USA FAA and also in Australia and certainly seems to be the
system of the future. Here is an extract from the FAA Fact Sheet dated
2 May 2006

That is still true in part for Australia but ASA (AirServices Oz) has
recently (about 20 July) withdrawn its RFP for lower airspace ADS-B.
Upper airspace appears to still be going ahead but the application of
ADS-B to ALL aircraft - the original aspiration - appears to have been
somewhat curtailed.

AFAIK there are no current suitable low power consumption airborne units
on the market and the ground station network being implemented will
probably not be as extensive as we'd hoped.

Obviously, widespread implementation in the US will have the same
trickledown effect worldwide as almost all other en route systems from
A-N ranges to GPS but there are problems. Avweb discussed some of these
- I'll see if I can find the reference.

This may not have helped your case

GC