Orlando, FL-Remember MAVs? (see DN 5.18.98 or
Well, those Micro Air Vehicles have evolved from prospective hand-launched
aircraft a few inches in size to what Sam Wilson, head of the MAV development
program at DARPA (the Defense Advance Research Project Agency), calls "flying
RUGS," or Relocatable Unattended Ground Sensors.
Originally these model-airplane-appearing hand-sized systems were to be
carried by a soldier and launched to scout the local area, including urban and
interior spaces. At the AeroSense conference here last week, Wilson highlighted
recent technology advances which change the scope and performance of such
vehicles. While MAVs were seen as fixed-wing aircraft, such a configuration,
without any complex wing flaps, had its top speed and slowest speed (in tens of
mph) very close together. This narrow envelope, he pointed out, doesn't work
well for maneuvering within confined spaces. Also, a fixed wing has to keep
flying to function, limiting its endurance.
What DARPA planners now envision is a more helicopter-like vehicle using a
ducted fan (essentially a propeller mounted inside a cylindrical wing),
according to Wilson. "It could theoretically go up to 80 knots or hover," he
noted. As a video clip demonstrated, the shrouded prop allows an operator to
safely snatch the vehicle out of the air or launch it easily. This type of
system would not fly constantly but "perch and stare," as Wilson called it, say
on the corner of a building or inside it, for extended periods of time-thus the
Contributing to such a scenario are new developments in microelectronics.
Wilson cited cameras that weighed 2 grams a few years ago now being "match-head
size, 12 to the gram. GPS systems once the size of a cigarette pack are
watch-size today" thanks to cell phone electronics that meet Enhanced 911
requirements. And cheap, tiny lasers with only a 30m range will be used for
obstacle avoidance, he added.
For propulsion, Wilson said two systems seem most viable: a diesel that runs
on readily available JP-8 jet fuel and a thermo-electric device deriving power
from heat transfer at an exhaust pipe. Both also offer less noise than other
The perch-and-stare routine and a form of "snooze" mode offer some
operational advantages, he noted. For example, a 5-lb, 9-inch diameter baseline
vehicle would require 1,500W to fly for an hour. The same MAV could function for
a week †or up to 3 months in a sensor watching mode, according to Wilson.
He cited operation could be modified to achieve 20 minutes of flight, one month
of watching, and 2.5 days of transmitting without recovery or refueling.
Contributing to this power conservation, algorithms will permit only tracking
moving objects (changing pixels) and transmitting such updated information. The
baseline vehicle is "dense" enough, Wilson said, to be gust resistant when
perched. But if blown off, it should react quickly to restart the engine and
reposition itself safely.
Wilson said MAV missions will include working with and aiding ground robotic
systems: detecting people around or threatening a ground robot or troops;
scouting for hazardous holes a ground vehicle might encounter; and validating
selection of firing targets.
Finally, while some components may cost thousands of dollars today, Wilson
noted the goal is a vehicle cost of $700 each. To achieve this, volume component
production would be needed along with such construction methods as "foaming" the
vehicle in place around the wiring and frame structure.