On Jan 24, 10:00*am, Jim White wrote:
At 04:08 24 January 2009, Eric Greenwell wrote:

I'm also skeptical of the "in the pipeline" claim, unless that means
"I've heard of some stuff that could do the job but it's not even on
it's way *to certification because there aren't even any specifications
for it yet".

Why is progress always seen as impossible?

http://www.mitre.org/work/tech_paper...34/07_0634.pdf

Jim

Why? Because in the USA there is huge existing infrastructure
including SSR, TCAS-II equipped aircraft and even down to PCAS that
UAT's sort of turns on its head. Then more recently there is
competition for data services from XM weather, Iridium, etc. and
security/hacking concerns with UATs (want to shut down huge parts of
some airspace with a transmitter and a laptop spoofing aircraft all
over the place? - supposedly one reason some of the Australian
adoption slowed down.). Then there is regulation/bureaucracy that has
to catch up with possible technology changes. While ADS-B promises a
lot people keep blurring the ADS-B-out capabilities like the Mitre low-
end prototype UAT and all the things like ADS-B-in with TIS-B/FIS-B
etc. that it cannot do.

Meanwhile Mode-S transponder technology with 1090ES for ADS-B keeps
getting smaller, less power consumption, etc. With Europe taking the
lead (ironically by largely dragging their feet on anything besides
1090ES). I'd expect to see continuing competition in the 1090ES space.
Like the impressive looking Trig TT21 transponder. I fly with a Mode-C
now, which does me fine. UATs have no appeal to me for the foreseeable
future for where I fly in high traffic areas, and if I had to I'd
rather pay $2,000 or so for a Mode-S 1090ES unit that is fully
compatible with existing infrastructure than $500 or $1,000 (at a
guess) for something that is not (and has anybody seen pricing yet on
an ADS-B UAT?). In future UATs hold some advantages, including better
uplink data, better coverage, etc. but I would not hold my breath that
early or low-cost units will offer anything above what you can do with
1090ES. Building a box is relatively easy, changing infrastructure is
not.


Darryl