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Powered, aerial vehicles that do not carry human operators; that
use aerodynamic forces to provide vehicle lift and can fly autonomously or
piloted remotely are called Unmanned Aerial Vehicles (UAV). Envisioned as early
as 1915, early UAV’s were little more than remote controlled military targets.
A key determining factor in their classification as UAV is whether or not they
are recoverable. Cruise missiles for instance, while pilotless and remotely
controlled are not considered UAV’s because the vehicle is the weapon itself
and therefore unrecoverable.
Primarily developed through military research and development,
civil application continues to grow and includes firefighting, security,
search, rescue and surveillance. UAV’s have the potential to create ad-hoc
networks that greatly reduce the hops from source to destination. Through use
of directional antenna instead of omni-directional antenna, issues such as
capacity limitation and jamming can be largely eliminated. UAV’s can also be
used for remote sensing applications that gauge electromagnetic spectrum
through visual, infrared or near infrared cameras. Biological and chemical
sensors can be used to detect airborne microorganisms and analyze the
concentrations of elements in the air.
Six functional categories have been established to classify modern
UAV’s including:
- Target and Decoy
- Reconnaissance
- Combat
- Logistics
- Research and Development
- Civil and Commercial
With capabilities ranging from handheld flyers with a 2km range
through vehicles able to reach speeds greater than Mach 25 and low earth orbit,
the original intent of UAV’s was to minimize civilian casualties. Costs range
from a few thousand dollars to tens of millions of dollars with weights from
less than a pound to over 40,000lbs.
UAV’s can be powered electrically thru brushed, brushless or
external can motors. An electric UAV has no exhaust noise and can temporarily
minimize prop noise to tactical advantage. While there are very few options for
improving the performance of internal combustion Predator electric UAVs can
overcome the endurance gap through "hybrid'' systems. This is accomplished through using multiple energy
sources including: high-efficiency fuel cells, solar energy (especially at
high-altitude), high-performance electrical energy storage, and energy
conserving power electronics.
With the ultimate goal of replacing the human pilot, UAV autonomy
seeks to develop ‘smart’ machines. With intelligence processing capability and
decision making abilities in line with how human pilots would respond to a
variety of battlefield and real world situations.
Key developmental areas before an autonomous UAV can be realized
include:
- Sensor Fusion: Combining information from different sensors for
use on board the vehicle.
- Communications: coordination between multiple agents using
incomplete/imperfect information.
- Motion/Path Planning: Determining optimal path while meeting
objectives and avoiding obstacles.
- Trajectory Generation: Determining optimal control maneuvers from
one location to another.
- Task Allocation/Scheduling: Optimal distribution of tasks with
time and equipment constraints.
- Cooperative Tactics: Formulating optimal activities between agents
to achieve mission scenario.
Besides the existing commercial aviation services of agriculture,
civilian policing, scientific services, mapping, and remote sensing, new
markets are also seen as viable, according to market surveys. Particularly the
telecommunications services segment where endurance platforms have become a
major rallying point for commercial UAV concepts, particularly among U.S.-based
developers. Continued advancement of UAV’s is dependent on a number of
commercial and military developments and continued government funding. Some of
the recent advancements include Optionally Piloted Vehicles (OPV), hydrogen
powered UAV and autonomous aerial refueling. We may not know which direction
the future of Unmanned Aerial Vehicles lies, but we can be sure of one thing…we
won’t need a pilot to take us there.
Sources:
http://www.afa.org/mitchell/reports/MS_UAV_0710.pdf
http://en.wikipedia.org/wiki/unmanned_aerial_vehicle
http://www.fas.org/irp/program/collect/uav.htm
http://www.theuav.com/
http://www.gizmag.com/firebird-intelligence-gathering-aircraft-system/18604/
http://www.gizmag.com/boeing-phantom-ray-flight-test/18610/
http://homepages.wmich.edu/~ldong/paper/0111.pdf
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