On 11/1/2010 12:59 PM, Eric Greenwell wrote:
On 11/1/2010 6:50 AM, bildan wrote:
From "AVweb":


The FAA has estimated overall costs on the user end could range from
$2.5 billion to $6.2 billion overall. And the FAA currently plans to
mandate only ADS-B Out by 2020. However, ADS-B Out "essentially
replicates existing domestic radar coverage," meaning adopters would
bear a cost but see few new benefits.

I'm reminded of the situation that has existed with personal computers
for decades: advanced computers with more powerful processors (8 bit,
then 16 bit, 32 bit, and now 64 bit) appear on the market years before
the software is able to take advantage of the added power. While
proponents of ADS-B point at how well the hardware (ground stations,
e.g.) is being implemented, it appears the people, protocols, and
software are lagging significantly behind.


Again, most people of mixing together ADS-B and "Nextgen" in the same
bucket. ADS-B is a very small and limited part of the FAA's Nextgen
plan. It is purely a position reporting infrastructure, part of which
is on the aircraft (either a 1090ES or UAT transmitter with an optional
receiver). The other part is a network of ground stations which are
interfaced with the existing ATC infrastructure so that controllers can
see ADS-B equipped aircraft on their scopes and conversely, so that the
ground stations can transmit TIS-B info for Mode C/S transponder
equipped aircraft to ADS-B IN equipped planes.

The ADS-B part of Nextgen is clearly defined and is being deployed as we
speak. The ground stations are being deployed, and the interfaces to
the existing ATC infrastructure have been designed, tested, and are
being implemented as the ground stations are being installed.

Slowly, we are seeing the introduction of ADS-B IN and OUT compliant
avionics coming onto the market. Again, the technology exists and is
currently being deployed. The big problem is cost and affordability,
both for GA and the big iron. A big part of this problem is due to the
overly cumbersome certification and TSO requirements that the FAA has
established for this equipment.

The big uncertainties that everyone is talking about are the additional
Nexgen components that the FAA is planning to completely redesign how
they control IFR aircraft to increase direct routings, permit direct
descent profiles, etc. to hopefully provide significant fuel burn
savings to the airlines. This redesign is enabled by the increased
resolution and accuracy provided by the ADS-B avionics, vs what can be
resolved by conventional radars interrogating Mode C/S transponders.

For situational awareness in a VFR environment, the bigger Nextgen
issues are completely irrelevant. What is important is that we can see
other aircraft and they, and ATC, can see us. That part of ADS-B works.
The challenge is to get the price down so that people will actually
buy it before they are forced to in 2020 or beyond.

--
Mike Schumann