IEEE Consumer Electronics Magazine - November/December 2021 - 13

Table 2. Example of contemporary flight controllers.
UAV Components
Processor
Memory
Accelerometer
Gyroscope
IMU
Magnetometer
Barometer
Cost
Pixhawk Cube Orange
32-bit ARM-M7 @ 400 MHz
1 MB RAM, 2 MB flash
Three 3-axis accelerometers ICM20948
/ ICM-20649 / ICM-20602
Three 3-axis gyroscopes ICM20948
/ ICM-20649 / ICM-20602
One 3-axis magnetometer ICM20948
MS5611X5
$250.00
location
coordinates, which can be set up before
the flight by specifying each point's latitude, longitude,
and altitude, that creates a route so that
a UAV can fly autonomously from one waypoint
to the next. The flight controller can also be programmed
to make the UAV loiter in a specific
location. The flight controller automates the
UAV flight with the help of sensors, throttle, servos,
and payloads that are connected to the
flight controller. The autopilot capabilities
depend on the flight controller's firmware. All
the commands are programmed on a computer
before the flight and then loaded to the flight
controller. Table 2 describes the processing
power, memory, IMU components, and cost of
three of the most common flight controllers: the
Pixhawk Cube Orange, Lockheed Martin Kestrel
v3.1, and CUAV V5 NANO.
3. PROPULSION SUBSYSTEM: UAVs can utilize a
variety of propulsion subsystems depending on
the size, type, and mission of the UAV.
Fuel Engines: UAVs can utilize the same
engine technologies like that of the aircraft. The
UAV engine can be a piston engine, whether a
two-stroke engine such as the LYCOMING EL005,
or a four-stroke like the Rotax 914. UAVs can
also be powered by jet propulsion, such as turbofan
and turboprop engines. The Honeywell
T76, for instance, is a turboprop engine found in
General Atomics's MQ-9 Reaper. The Rolls Royce
F137 is an example of a turbofan engine, which is
November/December 2021
LockheedMartin
Kestrel
v3.1
CUAV V5 NANO
DSP @ 500 MHz
32 MB RAM, 32
MB flash
One 3-axis
accelerometer
One 3-axis
gyroscope
One 3-axis
magnetometer
Absolute and
differential
sensors
$5,000.00
32-bit Arm-M7 @ 216 MHz
512 KB RAM, 2 MB flash
Three 3-axis accelerometers
ICM-20602 / ICM-20689 / BMI055
Three 3-axis gyroscopes ICM20602
/ ICM-20689 / BMI055
One 3-axis magnetometer
IST8310
MS5611
$183.42
used by the Northrop Grumman's RQ-4 Global
Hawk and MQ-4 C Triton.
Depending on the engine type, a UAV can be
powered by a variety of fuel types such as kerosene,
diesel, gasoline, biodiesel, methanol, ethanol,
or liquefied petroleum gas (LPG). Engines
usually have a higher noise level as compared to
electric motors, but they tend to have better
endurance. The Aerosonde HQ by Textron Systems
with the LYCOMING EL-005 flew over the
Atlantic for 26 h and 45 min in stormy weather,
using only a gallon and a half of fuel.6 Table 3
describes the maximum power, weight, fuel
type, and cost for each of the aforementioned
engine types.
Electric Motors: UAVs that runonelectric
motors usually fly for a shorter period as compared
to those being run on fuel engines, but
they have the advantage of being lighter, quieter,
and easier to launch. Motorized UAVs use
brushed motors that are powered by a battery,
mostly lithium-polymer (Li-Po). Additionally, an
electronic speed controller (ESC) circuit is
required to give the flight controller control
over the speed and direction of rotation of an
electric motor. An ESC works by adjusting the
frequency of the transistors and creating a
rotating magnetic field that rotates the motor.
The speed of the motor is proportional to the
switching frequency of transistors of the ESC
circuit.
13
IEEE Consumer Electronics Magazine - November/December 2021

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