On Sat, 12 May 2007 10:27:42 -0700, Richard Riley
wrote in
:

On Sat, 12 May 2007 16:01:01 GMT, Larry Dighera
wrote:


Upon what credible information do you base your prognostication?

My day job.

The technology for autonomous see and avoid isn't here yet, even in a
transponder-mandated environment. It will be soon, but to fly a UAV
in the NAS outside of a restricted area you have to have visual
contact with the vehicle. See and avoid without transponders will
take longer. See and avoid cars, houses and people on the ground
while crashing with engine out and partial control will take even
longer. Once that's in place (10 years at least, likely 20) there
will be another 20 year lag before it's politically acceptabe.

From the information I was able to find, it looks like sense-and-avoid
is imminent:


http://www.shephard.co.uk/UVOnline/d...3-8df3c5e489fb
USAF progresses passive sense-and-avoid

Dr John McCalmont from the US Air Force Research Lab at Wright
Patterson AFB gave the army aviation community here in Atlanta a
valuable insight into USAF work on sense-and-avoid systems,
indicating that technical solutions to the problem are closer than
many have assumed.

He showed a video in which a prototype system fitted to a manned
Learjet for the test picked up an intruding King Air turboprop on
a collision course nearly twice as far way as a human pilot could
have. This is an encouraging indication that UAV sense and avoid
systems are likely to provide significantly more than the FAA
mandated ‘equivalent level of safety’ to manned ‘see and avoid’
procedures.

The prototype system is completely passive, using a
high-resolution day TV camera with a field of regard of 110
degrees either side of the nose and flow vector processing
software. This assesses the direction of visual flow – the
direction and speed at which the world appears to be moving past
the aircraft – and looks out for anomalies that appear to be
moving differently, particularly they don’t appear to be moving at
all, that being a reliable indicator of something on a collision
course.

The technology has grown out of DAS missile approach warning work
– Dr McCalmont has a background in defensive EW equipment for
combat aircraft. This is actually a much easier problem to solve,
he said.

Sized for a Predator/Warrior UAV, the current system weighs about
25 lb, so clearly needs to shrink for smaller vehicles. For larger
aircraft such as Global Hawk a radar can be added.

Regulatory requirements recently and suddenly changed from
insisting on human control of a UAV in a collision avoidance
manoeuvre to favouring complete automation of the process, he
said.

----------------------


http://www.colorado.edu/AcademicAffa...5_7177_194.pdf
26 - 29 September 2005, Arlington, Virginia
Development of a Sense and Avoid System

----------------------

http://www.uavworld.com/_disc1/00000042.htm
"The goal of the test was to be able to make a decision based on
radar data in enough lead time to manoeuvre the test aircraft to
avoid a close encounter with the intruder aircraft," said Glenn
Hamilton, UAV subsystems project manager at Dryden.

----------------------

[...]
You've got to agree, that NAS airspace is a finite resource.
As such,there is doubtless an amount of air traffic beyond which it could be
said that its capacity has been exceeded. Given that today there are
some ~5,000(?) flights aloft at any given moment, what might the
maximum number be?

[...]

There are only so many cubic miles in the NAS. But in most parts of
the country, if you look up at the sky most of the day you will see no
airplanes. Airplanes are concentrated in a few areas. If we improve
the technology for how we route and control airplanes, we can easily
fit more - a LOT more - into the NAS.

So what is the maximum NAS capacity today?

What will that figure be under NextGen?

In any event, it's not unlimited.