On Thu, 24 Mar 2016 09:11:31 -0400, Vaughn Simon wrote:

On 3/24/2016 8:07 AM, Larry Dighera wrote:

http://www.avweb.com/avwebflash/news/NASA-ADS-B-Could-Allow-Drones-In-NAS-225878-1.html

NASA: ADS-B Could Allow Drones In NAS
By Mary Grady

Large-scale drones could safely fly in the National Airspace System by using
ADS-B technology,

The article is so vague that one can't really tell what they are doing.
But for drones in the national airspace system, ADS-B can never be
more that part of the answer for detecting and avoiding other aircraft.
Similarly, "Synthetic Vision" can only tell you what should be there,
not what really is, because it normally depends on a database of
obstructions. Further, "Sense and Avoid" is not necessarily the same as
"See and Avoid".

Current regulations do not require all general aviation aircraft to
equip with ADS-B (or any beacon/transponder technology). Plus there is
always the possibility of equipment malfunction or pilot error, which
could mean that any given airplane could go undetected by ADS-B.

Any drone technology that falls short of true video and radar "See and
Avoid" should be considered a non-starter. Don't buy the ADS-B Cool-aid!


Watching the Bloomberg news ticker on TV a bit ago, I saw that two million
drones were sold in the US this year, and the total is expected to be twenty
million by 2020. If this avalanche of UAS doesn't overwhelm the ATC system, I
will be surprised.

But to your points.

First, ADS-B is dependent on weak satellite radio signals for positional data
of the aircraft in which it is installed. As you mentioned, such a system is
vulnerable to the vagaries of electromagnetic propagation, including solar
coronal mass ejections, as well as spoofing by the ADS-B cockpit equipment and
higher powered radio transmitters potentially overwhelming the satellite signal
and taking control ...

https://homeland.house.gov/files/Testimony-Humphreys.pdf
STATEMENT ON THE VULNERABILITY OF CIVIL UNMANNED AERIAL VEHICLES AND OTHER
SYSTEMS TO CIVIL GPS SPOOFING TODD HUMPHREYS THE UNIVERSITY OF TEXAS AT
AUSTIN
1. Summary
Military Global Positioning System (GPS) signals have long been encrypted
to prevent counterfeiting and unauthorized use. Civil GPS signals, on the
other hand, were designed as an open standard, freely-accessible to all.
These virtues have made civil GPS enormously popular, but the transparency
and predictability of its signals give rise to a dangerous weakness: they
can be easily counterfeited, or spoofed. Like Monopoly money, civil GPS
signals have a detailed structure but no built-in protection against
counterfeiting. Civil GPS is the most popular unauthenticated protocol in
the world.

The vulnerability of civil GPS to spoofing has serious implications for
civil unmanned aerial vehicles (UAVs), as was recently illustrated by a
dramatic remote hijacking of a UAV at White Sands Missile Range. The
demonstration was conducted by the University of Texas Radionavigation
Laboratory at the behest of the Department of Homeland Security (DHS). From
a standoff range of a half mile, the University spoofer commandeered the
UAV and induced it to plummet toward the desert floor. The results of this
demonstration will no doubt factor into the Federal Aviation
Administration’s (FAA’s) plans for integrating UAVs into the national
airspace.

Hacking a UAV by GPS spoofing is but one expression of a larger problem:
insecure civil GPS technology has over the last two decades been absorbed
deeply into critical systems within our national infrastructure. Besides
UAVs, civil GPS spoofing also presents a danger to manned aircraft,
maritime craft, communications systems, banking and finance institutions,
and the national power grid. ...


The GAO http://www.gao.gov/assets/280/275335.html had this to say:

Routine UAS access to the national airspace system poses technological,
regulatory, workload, and coordination challenges. A key technological
challenge is providing the capability for UASs to meet the safety
requirements of the national airspace system. For example, a person
operating an aircraft must maintain vigilance so as to see and avoid
other aircraft. However, because UASs have no person on board the
aircraft, on-board equipment, radar, or direct human observation must
substitute for this capability. No technology has been identified as a
suitable substitute for a person on board the aircraft in seeing and
avoiding other aircraft. Additionally, UASs' communications and control
links are vulnerable to unintentional or intentional radio interference
that can lead to loss of control of an aircraft and an accident,
[Footnote 2] and in the future, ground control stations--the UAS
equivalent to a manned aircraft cockpit--may need physical security
protection to guard against hostile takeover. Although DOD has achieved
operational successes with its use of UASs in Iraq and Afghanistan,
accidents of varying degrees of severity have resulted from UAS
reliability problems and human factors issues, i.e., equipment designs
that did not fully account for human abilities, characteristics, and
limitations. Our analysis of 4½ years of DOD's data indicates that UAS
component failures caused about 65 percent of the accidents and human
factors issues--a common challenge in new technology--caused about 17
percent of the accidents. Because a regulatory framework to ensure UAS
safety does not exist, ...

Predictions of the impact of UASs on the national airspace system are
speculative because there are few data upon which to base predictions.
Predictions become even more speculative in view of RTCA's recent
estimate that minimum standards for UASs--a prerequisite for routine
UAS access to the national airspace system--will require about another
10 years to complete. One study notes that more needs to be known about
the needs and capabilities of future UASs as well as the potential
market, but concluded that their operations could have a significant
and potentially disruptive impact on aviation by affecting capacity and
introducing more complexity. In 2007, RTCA's Special Committee 203
reported similar concerns, indicating that UASs will create some unique
challenges because they operate differently from typical manned
aircraft. While manned aircraft generally go from one location to
another, UASs may hover or circle in one location for a significant
time. Additionally, UAS speed, maneuverability, climb rate and other
performance characteristics may differ substantially from those of
conventional aircraft. The committee believes that these
characteristics could affect air traffic flow, air traffic controller
workload, and departure and arrival procedures, among other things.
Similarly, FAA officials noted that UASs pose airport safety and
capacity questions that require further analysis.

Most of the experts stated that the impact of UAS's would be at least
as significant as that of additional manned aircraft on airspace,
airports, and air traffic control.