Journal Article: 2011 AUVSI Student UAS Competition
The University of Texas at Arlington
Autonomous Vehicles Laboratory
2011 AUVSI Student UAS Competition Journal Paper
Submitted: May 23, 2011
Student Team
Daniel Glowicz, Jonathan Efinger, Mariah Bacchus, Martin Dickson, Nicholas Yokell
Faculty
Dr. Atilla Dogan - Mechanical and Aerospace Engineering
Dr. Brian Huff - Industrial & Manufacturing Systems Engineering
Dr. Kamesh Subbarao - Mechanical and Aerospace Engineering
Abstract:
This paper describes a system for semi-automated reconnaissance for the AUVSI 2011 Student
UAS Competition. An aircraft with a payload autonomously takes off and navigates via specific
GPS waypoints to a predetermined search area where it performs a search pattern. The payload is
a camera mounted on a pan-tilt-zoom platform and it is used in searching for targets. The
location and other parameters of the target are then identified and given to judges. Success
depends on proficiently controlling mission elements including; autonomous takeoff and landing,
autonomous control, waypoint navigation, mission flexibility (the ability to change missions
before and during flight), and target interpretation. Discussed in this text are the rationales,
architectures, components, and processes involved in achieving this goal. The system design is
described in terms of Project Chartering, System Requirement Review, Baseline Design,
Conceptual Design, Feasibility Studies, Preliminary Design, Unit Testing, Detailed Design, and
Integrated Testing. Additionally, Safety features such as structural reinforcements, the ability to
switch to manual control at anytime during the flight, and safety-specific engineering processes
are addressed.
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1
Introduction
During this time of the global war on terror, the safety of the troops is of utmost concern
especially in the vast, dangerous and unknown terrains where they have to fight. Unmanned
Aerial Vehicles, from the Global Hawk to the Predator and also the Scan Eagle, have been vital
in reducing troops’ risks by providing a less fatal but very effective way of obtaining
reconnaissance on their surroundings. As the years have gone by, the difficulty of the unmanned
systems missions have increased, however, so have their technological advances. The Annual
AUVSI Student Unmanned Aerial Systems Competition, formerly known as the Student
Unmanned Aerial Vehicle competition, was created to urge students in this technological
frontier.
The competition is a simulation of a plausible US Marine UAS support mission. The mission
objective is to develop a system which can provide the Marines with information such as
locations of targets in a danger zone. An unmanned vehicle, after a manual or automatic takeoff,
will autonomously navigate into a predefined combat zone via a given waypoint corridor. In this
combat zone, the vehicle is to find and identify targets for the Marines. The system is required to
be robust as this is a battle zone and the situation may change at any moment and it is vital that
the system responds accordingly.
The change of the competition name to from vehicles to systems is indicative of the degree
planning necessary in meeting the mission requirements. This report discusses the approach of
the University of Texas at Arlington (UTA) Autonomous Vehicles Laboratory (AVL), system’s
design, expected performance and results as well as safety considerations made in effort to
succeed in the mission.
2
Mission Requirements
The mission requirements, as specified in the competition rules, have five major parts which are
summarized in the table below.
Table 2-1: Key Performance Parameters (From 2011 AUVSI SUAS Rules)
Parameter
Autonomy
Imagery
Threshold
During way point navigation
and area search.
Identify any two target
characteristics:
 Shape
 Background color
 Orientation
 Alphanumeric
 Alphanumeric color
Objective
All phases of flight, including takeoff
and landing
Identify all five target characteristics
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Target Location
Mission time
In-flight re-tasking
3
Determine target location
ddd.mm.ssss within 250 ft
Less than 40 minutes total
Imagery/location/identification
provided at mission
conclusion
Add a fly to way point
Determine target location within 50 ft
20 minutes
Imagery/location/identification
provided in real time
Adjust search area
Methodology
In order to successfully complete the mission, an engineering approach was taken to address the
requirements given in the rules. The approach was to methodically design a system that will
accomplish most or all of the mission phases. The methodology chosen is similar to the ones
which top design teams use and is shown below.










4
Project Chartering
System Requirement Review
Baseline Design
Conceptual Design
Feasibility Studies
Preliminary Design
Detailed Design
Unit Testing
Integrated Testing
System Tuning and Rehearsals
Project Chartering
A charter for this project was issued on August 31, 2010. This document formally authorized the
team’s embarkation into the 2011 AUVSI SUAS Competition. The main purpose of the
document is to ensure that all the members of the team are aware of the competition and the level
of commitment it requires. The document contains a project description, available resources, a
statement of work, a work breakdown structure, important AUVSI contact information,
competition milestones, the above methodology and a project timeline.
5
System Requirements Review
A review session was conducted in which the competition rules were thoroughly analyzed in
order to develop detailed system requirements and to generate questions for clarification at the
competition University Day. The table below highlights the system requirements defined at this
meeting. The threshold level implies the bare minimum for the system, while the objectives are
the goals and the stretch objectives are bonus for the system.
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Journal Article: 2011 AUVSI Student UAS Competition
Table 5-1: System Requirement Summary
Capability Level
Threshold
Threshold
Threshold
Threshold
Threshold
Threshold
Threshold
Threshold
Threshold
Threshold
Objective
Objective
Objective
Objective
Objective
Objective
Objective
Objective
Objective
Objective
Stretch
Stretch
Stretch
Stretch
Stretch
6
Capability
Add a fly-to waypoint
Change altitude while in automatic mode
Change airspeed while in automatic mode
Automatically fly waypoints
Automatically fly search area
View 60 degrees in every direction vertically below the air vehicle
Print 2/5 target characteristics at conclusion
Print target location within 250’ at conclusion
Conclude within 40 minutes
Address Safety issues
Automatically take off
Adjust the search area and display the changes
Display/Print 2/5 target characteristics during flight
Display/Print 5/5 target characteristics during flight
Display/Print target location within 250’ during flight
Display/Print target location within 50’ during flight
Automatically land
Print 5/5 target characteristics at mission conclusion
Print target location within 50’ at mission conclusion
Conclude at 20 minutes
Print 4/5 enroute-off-flight-path target info at mission conclusion
Display new search area (for Pop Up target) during flight
Print Pop Up target image & location within 250’ at mission conclusion
Automatically id/cue >= 2 targets with >= 50% correct
JAUS Compliance
Baseline Design
The baseline design phase was an opportunity for team members to come up with open ended
creative ideas for solving the design problem. The ideas proposed were diverse varying from
unconventional aircrafts such as a tilt rotor to a simple modification of a conventional aircraft.
The decisions made in this phase were twofold:


Selecting an aircraft and
Selecting an auto controller
A figure of merit system is used in explaining how these decisions were made. The figures of
merit for air vehicle selection and auto controller selection are shown below. Each merit was
given a weight factor (on a scale of 1 to 5) in order to amplify its importance. The grading
scheme is as follows

Strong point: 1
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

Indifference or unknown: 0
Weakness: -1
The table below shows the figure of merit for aircraft selection.
Fixed Wing Prop
Tilt rotor
Helicopter
Fixed Wing Jet
Merits
Payload Volume to vehicle weight ratio
Cost of parts
Legacy
Ease of implementation
Compatibility with auto Controller
Speed
Maneuverability in search Area
Piloting experience
Blimp
Table 6-1: Air Vehicle Figure of Merits
-1
-1
0
-1
0
-1
1
0
1
0
1
1
1
1
0
1
1
-1
0
-1
-1
1
1
-1
-1
-1
0
-1
0
-1
1
0
1
-1
0
0
0
1
-1
-1
-11
23
-7
-11
-5
W. F.
4
4
3
3
5
3
3
5
Product Total
A conventional fixed-wing propeller-driven aircraft was chosen because it has the least
unknowns, it is easy to implement, favorable to most auto controllers and the most familiar to the
safety pilot, hence the safest choice. The table below shows the FOM for the auto controllers.
Cost
Experience with it
Package
Accessibility
Flexibility
Meets all autonomous objectives
1 -1 -1
1
0
0
1
1
1
1
0
0
0
0
1
1
1
0
Product Total
21
5
3
The MicroPilot solution was chosen because it was the most cost effective
already possesses two systems. Additionally, the team has about five years
MicroPilot and has performed well in two UAV competitions using it.
University of Texas at Arlington Autonomous Vehicles Lab
Stargate
Kestrel
W. F.
4
5
4
3
3
5
Piccolo
Merits
MicroPilot
Table 6-2: Vehicle Configuration Figure of Merits
1
-1
0
-1
1
-1
-6
choice as the team
of experience with
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7
Conceptual Design and Feasibility Studies
Since a decision had been made on the autonomous flight system, the conceptual design phase
was spent in creating different set-ups for meeting the imagining requirements. The candidate
designs were as follows.




Fixed Wide-Angle (120˚ FOV) High Definition Camera
Gimbaled Camera Stabilized by MP board
Gimbaled Camera controlled by a processor programmed by the team
Multiple Fixed Cameras with a Video Multiplexer
The Feasibility of each these options were determined and a decision on a design concept to
move forward with was made using the figure of merits table shown below.
Multiple Fixed Cameras
In House Stabilized Camera
W. F.
3
MP Stabilized Camera
Merits
Single Fixed Cam
Table 7-1: Conceptual Design Figure of Merits
1
0
-1
-1
Incremental Development
4
1
0
-1
-1
Reliability
4
1
0
0
-1
Available Resources
3
0
0
0
-1
Our Experience
4
1
1
-1
-1
HW Complexity
3
1
0
-1
-1
Weight
4
-1
1
-1
-1
Cost
4
-1
0
0
-1
Flexibility
4
-1
1
1
1
Ingenuity
2
-1
1
1
1
Product Total
4 14 -12 -23
The gimbaled camera stabilized by the MicroPilot design was chosen because it eliminates the
need for a heavy wide angle lens yet gives the ability to see sixty degrees in all the directions
below the aircraft. Additionally, a stabilized camera means that the camera can move
independently of the aircrafts rotations. Since MicroPilot does the stabilization there will be no
need for an extra processor, its complexity and all the sensors and communication devices that it
will require.
Overall Risk
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8
Preliminary Design
During this phase, a general idea all the components going into the system were determined. The
premise was that a fixed wing aircraft controlled by the MicroPilot carries a stabilized gimbaled
camera which sends live video to the ground. On the ground, there is a Ground Control Station
for the MicroPilot and an imaging station for viewing the video. An image processing station
was also added in this phase. This station was added in order to initiate work by the team on
autonomous image recognition. A diagram of this system is shown below.
Left Aileron
Right Aileron
Elevator
Rudder
Throttle
Aircraft
Servos
Safety
Switch
Switch
MicroPilot
R/C RX
Roll
Pitch
Stabilized
Mount
Radio Modem
Data Link
R/C TX
Radio Modem
Pilot
Ground
Control
Station
OEM
Camera
Video TX
Air
Ground
Video Link
Video RX
Ground
Imaging
Joystick
Laptop
Imaging Station
Autonomous
Imaging
Processing
Team Liaison
Ground
Judges
Control
Figure 8-1: System diagram
The overall system canStation
be divided into the airframe, radio control, autonomous control, imaging,
communication and power subsystems.
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8.1 Airframe Subsystem
The R/C aircraft chosen is a SIG Kadet Senior ARF (Almost Ready to Fly) equipped with an
O.S. FX 0.91 in3 engine. The Kadet Senior is a stable fixed-wing airplane with a large wing area
and sufficient payload space. Additionally, since it is an ARF it has a short build time. The OS
FX 0.91 in3 is a powerful, reliable and easy to maintain engine with a top output of 2.8 hp. The
airframe is equipped with HS-81MG servos for the throttle, HS 645MG for rudder and HS645BB servos for the other surfaces, all of which are very durable and reliable. Additionally, a
few modifications were made to make the airframe more ergonomic. Modifications such as




Reinforcement of the firewall to withstand stresses from the more powerful engine.
Relocation of the throttle, rudder and elevator servos to increase payload space.
Creation of panel hatches for easy access to the batteries, payload and servos.
Replacement of stock main landing gear with composite to improve take-off and landing
stability.
A three view of the airframe with dimensions and tables of its characteristics and that of the
engine are shown below.
Figure 8-2: Three-view drawing of the SIG Kadet Senior (picture from ARF Manual)
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Table 8-1: Airframe Characteristics
Table 8-2: Engine Specifications
Aspect Ratio
Wing Area (ft2)
Wing Span (ft)
W/S (lb/ft2)
Fuselage Length (ft)
Fuselage Width (ft)
Weight Take-Off (lbs)
Weight Landing (lbs)
Engine Model
Displacement (cu in)
Bore (in)
Stroke (in)
RPM
Output (hp @ rpm)
Weight (oz)
Recommended Props
5.07
7.92
6.33
0.66
5.33
0.42
12
11.5
.91 FX (OSMG0591)
0.912
1.091
0.976
2,000 -16,000
2.80 @ 15,000
19.42
15x8, 16x6
8.2 Radio Control Subsystem
The R/C Subsystem is the subsystem used for manual control of the aircraft. The subsystem
includes an R/C Transmitter, R/C receiver, a safety switch and a glitch buster. A diagram of the
subsystem is shown below.
Aircraft Servos
Glitch Buster
Safety Switch
MicroPilot
R/C RX
Air
Ground
R/C TX
Pilot
Figure 8-3: Radio Control Subsystem diagram
8.2.1 Glitch Buster:
The glitch buster is a device made by Jomar electronics which amplifies and cleans servo input
signals and provides servo power isolation. It has 8 input and output channels and weighs about
an ounce. It was implemented as a safety measure to ensure that the servos receive clean strong
signals at all times because there are a lot of signal wire splits in the system. A picture of the
Glitch buster board is shown below.
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Figure 8-4: Jomar Electronics Glitch buster (from http://www.emsjomar.com/)
8.2.2 Safety Switch:
The safety switch is a custom-built device created by Reactive Technologies10 in collaboration
with NCSU11. It receives inputs from both the R/C receiver and the MicroPilot and it outputs
signals from either of them to the glitch buster. The switch is controlled by an input channel from
the R/C Receiver that allows the pilot to select which set of inputs is to be sent to the aircraft
servos. The pilot can manually bypass the auto controller during emergencies by switching
control directly to the R/C receiver. It has an added feature that in a case where the aircraft
losses signal from the pilot’s transmitter, the switch automatically turns control to the R/C
receiver which is preprogrammed to initiate a cut-throttle-spiral-to-the-ground maneuver. This is
a fail-safe maneuver implemented in compliance with the AUVSI competition rules. A picture of
the reactive technologies safety switch is shown below.
Figure 8-5: Reactive Technologies Safety Switch (from
http://www.reactivetechnologies.com/RxMux.html)
8.2.3 R/C Receiver:
The purpose of an R/C receiver is to allow the pilot to control the aircraft. It relays the signals
from the pilot’s transmitter to the aircraft. It is connected to both the auto controller and the
safety switch. Under normal conditions, the pilot can fly the aircraft through the auto controller
via the receiver. However in an emergency, the pilot can take direct control of the aircraft by
sending a signal to the safety switch. The R/C receiver selected for this UAS is a synthesized
Multiplex IPD 9 channel RX. This receiver was chosen because it is synthesized and can run on
almost any R/C frequency. Additionally it can be programmed to initiate a fail-safe maneuver if
the aircraft losses signal from the pilot’s transmitter.
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Figure 8-6: R/C Receiver (from http://www.multiplexusa.com/)
8.2.4 Pilot’s R/C Transmitter:
The pilot’s transmitter is the means by which the pilot can control the airplane. This transmitter
sends signals to the air vehicle’s receiver, allowing the pilot to fly either via the auto controller or
directly through the safety switch. The transmitter chosen is a Multiplex Royal EVO 9 channel
TX equipped with a frequency scanner. It is reliable, durable and versatile. It is versatile in the
sense that it allows the pilot to assign any of its switches to any of its channels. The frequency
scanner allows the transmitter to check for dirty or in-use R/C frequencies. This gives added
safety because the transmitter will be inactive if a channel is dirty and the UAV will not fly if the
transmitter is inactive (see safety switch section).
Figure 8-7: R/C Transmitter (from http://www.multiplexusa.com/)
The roles of a pilot are summarized below:



Ensure the auto controller flies the aircraft in a regular manner.
Update the team and the liaison on any irregularities during the course of the mission
Take control of the aircraft if there is a major malfunction
8.3 Autonomous Control Subsystem
The auto controller chosen is the MicroPilot MP2028g. It was chosen during the baseline design
phase because the team is familiar with the system and it meets design requirements. It is capable
of altitude hold, airspeed hold, coordinated turns and GPS navigation as well as autonomous
take-off and landing. It is also able to stabilize a gimbaled camera to compensate for the aircrafts
rotations. Additionally, it produces sufficient telemetry data which can be transmitted via a
modem link or overlaid unto a video as needed.
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The Autonomous subsystem comprises of the MP2028g board, its sensors and Ground Control
Station software
8.3.1 MP2028g Board:
The MP2028g is the base of the autonomous control subsystem. It is where all the flight
parameters are stored including airplane characteristics and the current flight plan. It weighs only
1 oz and measures 3.9 inch by 1.5 inch. It comes equipped with two pressure transducers, X-Y
gyros and a GPS unit. One of its pressure transducers is open to ambient air for altitude
measurements while the other is connected to a stagnation pressure tube for airspeed
measurements. A layout of the MP 2028 board is shown below.
Figure 8-8: MP2028g Layout (from Micropilot manual)
From the sensor data, the board determines the required action in order to achieve a desired flight
condition. The actual magnitude of the commands MP2028g issues to the aircraft servos are
governed Proportional-Integral-Derivative (PID) control loops which are tuned to the specific
airframe. It uses 12 PID loops which are:
1. Aileron from Desired Roll
2. Elevator from Desired Pitch
3. Rudder from Y-accelerometer
4. Rudder from Heading
5. Throttle from Speed
6. Throttle from Glide Slope
7. Pitch from Altitude
8. Pitch from AGL Altitude
9. Pitch from Airspeed Altitude
10. Roll from Heading
11. Heading from Cross Track
12. Pitch from Descent
8.3.2 Ground Control Station (GCS) Horizon Software:
The GCS software that comes with the MicroPilot is called HORIZONmp. Horizon displays
information in a Graphics User Interface (GUI) and allows the operator to monitor as well as
dynamically change flight parameters. It is also used to upload aircraft parameters and flight
plans to the auto controller. A screenshot of the GCS Horizon Software GUI is shown below.
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Figure 8-9: A screen shot of the GCS HORIZON Software GUI
The GCS also has a window which displays the camera’s projection and gives the camera center
location in UTM coordinates. A picture of this widow is shown below.
Figure 8-10: A screen shot of the Camera Status window showing camera center location
8.4 Imaging Subsystem
The imaging subsystem is the system used to identify targets. It is comprised of a roll-pitch
gimbaled camera, Image viewing and an Image processing station and components of the
autonomous subsystem such as the MicroPilot and GCS. A diagram of the imaging subsystem is
shown below.
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Images
Aircraft attitude
AIR
Micropilot
Gimbaled Camera
Stabilized Camera Positions
Camera
Orientation
Video
Desired
Camera Position
Image Viewing
Station
Target
Images
Video
Image Processing
Station
Auto detected Target
Parameters:
 Shape
 Background color
Desired Camera Positions
Ground Control
Station
Target
location
Ground
Team
Liaison
Almost Real Time
Actionable Intelligence
Judges
Figure 8-11: Imaging subsystem diagram
8.4.1 Roll-Pitch Stabilized Gimbaled Camera:
The aircraft carries a gimbaled camera for capturing in-flight video used in target search and
recognition. The camera rotates about the roll and pitch directions with respect to the aircraft.
The rotations are controlled by servos connected to the MicroPilot which makes them
compensate for the plane’s rotations. The camera used is a Sony FCB color OEM camera. It was
selected because it is light, has high quality images and a serial interface which allows zoom
(26x) control. Zoom control has not been implemented at the time of writing this report;
however, it is in the works. A picture of the camera in the gimbaled mount is shown below.
Figure 8-12: Roll-Pitch gimbaled camera
8.4.2 Image Viewing Station:
The image viewing station is where the Camera Operator works. The Camera Operator uses a
joystick to control the camera via the GCS. The operator is responsible for finding targets and
alerts others about it.
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8.4.3 Autonomous Image Processing Station:
This is a computer dedicated solely to autonomous imaging. A simultaneous video feed is sent to
the laptop which is running a program written using OpenCV. The program autonomously
detects shapes and their colors. The pictures below show the software detecting triangles.
Figure 8-13: Pictures of triangles automatically detected by the imaging program
8.5 Communication Subsystem
The communication subsystem is the means by which the ground subsystems communicate with
those in the air. This subsystem has two components: a two-way data link and a video link. The
data link is via two 900 Hz MaxStream Xtend radio modems while the video link is through a
2.4 GHz Black Widow Audio/Video transmitter and a diversity receiver.
Figure 8-14: Radio Modem, Video Transmitter and Diversity Receiver
8.6 Power Subsystem
A schematic of the power distribution is shown below. Lithium Polymer batteries were chosen
because they are light weight (1.1lbs total) and have high current capacities. The master switch is
a safety precaution to ensure that all the batteries are turned off when they are supposed to be.
11.1 V
1350mAh
Li-Pol
Radio
Modem
7.4 V
1000mAh
Li-Pol
6V
Regulator
7.4 V
4500mAh
Li-Pol
6V
Regulator
11.1 V
1350mAh
Li-Pol
MP
Master
Switch
8V
Regulator
Servos
OEM
CAM
Video
TX
Figure 8-15: Power distribution schematic
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9
Unit Testing
All the subsystems were tested individually to ensure they work as expected and in the cases
where they did not, the subsystems were redesigned to do so. R/C and autonomous flights were
performed, the camera stabilization system was bench tested and the communication links were
proven to work.
10 Detailed Design
During this phase of the process the interconnections between the subsystems were designed as
well as their placements. Consideration was also given to the methods in which the system as a
whole is used to perform the mission. The designs are described in the following sections.
10.1 Aircraft Layout
Each subsystem in the airframe was carefully grouped and some were mounted in metal boxes
and then placed in various sections of the aircraft with weight/balance and RF interference
considerations. Since some of the systems are connected via multiple wires Alden Pulse Lock
connectors were used to connect between them. These connectors are lightweight and provide
secure connections which are quick to release. The pictures below show some of the grouped
subsystems.
Figure 10-1: Power, autonomous and R/C subsystems and an Alden PL700 connector
10.2 Target Search Pattern and Target identification Procedure
A search needs to be performed that will maximize the use of the gimbaled camera and
MicroPilot’s capabilities in accomplishing the mission. A figure of the selected search pattern is
shown in Figure 10-2 below. It involves the camera operator performing a sweep while the
aircraft performs a back-and-forth pattern in and out of the search area. Upon target discovery
the GCS operator initiates either a right or left orbit depending on the location of the target. After
the target is identified the aircraft returns to its original path. The full target identification process
is described in two sections: the Operators loop and the Target editors loop. The operators are the
GCS and Imaging Station operators while the Target editor is in charge of determining the image
parameters and filling out the Real Time Actionable Intelligence Forms (RTAIF) and Mission
report.
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Right Orbit
Left Orbit
Key
Search Area
Flight Path
Camera Sweep Pattern
Orbit Flight Path
Target
Figure 10-2: Target Search Pattern
10.2.1 Operator Loop:
1. While manually steering & zooming the camera searching for targets, the Camera Operator
sees a target on his real-time video computer screen.
2. The Camera Operator loudly says “I see a target on the left (or right).”
3. The Horizon Operator commands the GCS to orbit the airplane to the left or right, depending
on the side stated by the Camera Operator.
4. While the airplane orbits, the Camera Operator attempts to compose a good image of the
target.
5. When the Camera Operator composes a satisfactory image of the target, he says out loud
“Acquire target!” and maintains the composition.
6. When hearing “Acquire target!” the Target Editor reaches over & presses the PrtSc button on
the Camera Operator’s computer.
7. The Camera Operator’s computer spools the print job without further manual intervention.
8. The Horizon Operator, upon hearing the Camera Operator say “Acquire target!” selects the
Horizon Camera Status Window and presses the Alt-PrtSc key combination.
9. The Horizon Operator’s computer spools the print job without further manual intervention.
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10. The Horizon Operator then commands the airplane to resume its flight plan.
11. This process is repeated until the entire search area is covered.
10.2.2 Target Editor’s Loop:
1. The printer prints the Camera Operator’s image.
2. The printer prints the Horizon Operator’s Camera Status window.
3. The Target Editor gets both hardcopies from the printer.
4. The Target Editor gets a blank Real-Time Actionable Intelligence Form (RTAIF).
5. The Target Editor transcribes the CAM Center “Hdg(deg.)”, UTM “zone”, “Easting”, &
“Northing” numbers into a custom Excel worksheet.
6. The Excel worksheet computes the latitude & longitude of where the camera’s boresight
intersects the ground.
7. The Target Editor transcribes the computed latitude & longitude to the RTAIF.
8. The Target Editor looks at the hardcopy target image and fills in as many of the RTAIF fields
as reasonably possible.
9. If time allows, the Target Editor estimates the direction of true north on the hardcopy of the
target.
10. If time allows, the Target Editor estimates the orientation of the target with respect to the
eight cardinal compass directions relative to the true north direction he drew on the hardcopy.
11. If time allows, the Target Editor adds the target orientation to the RTAIF.
12. The Target Editor gives the completed RTAIF to the judge & announces “This is real-time
actionable intelligence, Sir!”
13. This process is repeated until the all the targets are handed to the judges
11 Integration Testing
Integration testing is the phase where the fully integrated system as well as the methods
described in the detailed design section is to be tested and timed. Due to unforeseen
circumstances, no integrated testing has been done at the time of creation of this document.
12 Safety Features
Safety is an important part of engineering design. A lot of thought and planning has to go into
ensuring that personnel, equipment, and software are well-protected before, during and after the
missions. In this project, safety was stressed from the beginning and was emphasized through
the daily operation of the equipment in the Autonomous Vehicles Laboratory.
It was standard practice to use checklists and other means in order to prevent or minimize the
chance of injury. Some of the Standard Operating Procedures (SOP) for safety are characterized
below under Procedures for Accident Avoidance, Hardware Handling and Safety Devices.
University of Texas at Arlington Autonomous Vehicles Lab
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Journal Article: 2011 AUVSI Student UAS Competition
12.1 Procedures for Accident Avoidance
The general operation guidelines are:
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Checklists are used for procedures such as charging batteries to reduce the risk of damage
The airplane must be de-fueled after each flight.
Two team members are involved in the starting of the airplane’s engine. One secures the
plane while the other starts the engine.
Prior to each flight, the transmitter and receiver range checks are performed according to
the manufacturers’ suggested procedure.
All flights are conducted using a skilled pilot covered by AMA insurance.
No spectators or operators are allowed to stand in front or to the side of a rotating
propeller. All team members must remain behind the airplane while the engine is on.
All autonomous fine-tuning flights are conducted at a minimum altitude of 500 ft. This
altitude provides enough time to safely transition from autonomous to manual flight in
case of an emergency. Also, in the event of an engine failure, the conservative altitude
provides the pilot with a better chance of recovery.
12.2 Hardware Handling
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The tips of the propeller are painted white so that its boundary is visible at all times while
in rotation.
All battery charging ports and switches are placed inside hatches on the top aft of the
fuselage, away from the engine’s exhaust in order to prevent possible short-circuiting due
to fuel or oil ingestion.
The Lithium-Polymer batteries are charged outside the aircraft. This is done in order to
prevent improper charging which could result in fire or a possible explosion.
The master switch is turned off before the aircraft is loaded for transportation
Fuel is stored in a fireproof cabinet and never left unattended to or under the direct heat
of the sun.
All batteries onboard the aircraft are checked for proper charge prior to each takeoff in
order to prevent loss of control or communication during flight due to insufficient battery
charge.
All software files and programs pertinent to the autonomous project including the
operating system of the ground station are backed up and saved. This gives the ability to
retrieve the information in case of loss or damage of the original one
12.3 Safety Devices
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Glitch Buster – See Section 8.2.1 for more details
Safety Switch – See Section 8.2.2 for more details
Frequency Scanner – See Section 8.2.4 for more details
Master Switch – See Section 8.6 for more details
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Journal Article: 2011 AUVSI Student UAS Competition
13 Conclusion
Many considerations must go into the design of an autonomous aerial system, from
aerodynamics and structures to electronics and communications. This paper has briefly
described the University of Texas at Arlington’s Autonomous Vehicles Lab’s UAS. It described
the process by which the air vehicle was selected, the suite of electronics chosen to be integrated,
the tuning of the autonomous system and the modifications that took place on the airframe in
preparation for the AUVSI 2011 Student UAS Competition. The design phases were Project
Chartering, System Requirement Review, Baseline Design, Conceptual Design, Feasibility
Studies, Preliminary Design, Unit Testing, Detailed Design, and Integrated Testing. Safety was
also paramount. The participating students had to become familiar and fully aware to the
associated risks of dealing with flammables, internal combustion engines and propellers. Safety
compliance was addressed with safety devices, procedure checklists and constant reinforcement
of situational awareness. From the content of this document, the UTA AVL is confident that its
UAS is capable of achieving the performance goals of the 2011 AUVSI Student UAS
Competition.
14 Acknowledgements
We would like to thank the MicroPilot Company for their contributions in technical support and
product discounts. Additional thanks goes to Multiplex giving the team a wonderful deal on
their radios and other electronics. Special gratitude goes to Jay Francis from Reactive
Technologies for developing and donating two of his bypass boards to the AVL.
15 References
1. MicroPilot, “MP2028g - Autopilot.”2005,
http://www.micropilot.com/Manual-MP2028.pdf
2. MicroPilot, “HORIZONmp User Guide.”2004.
3. MicroPilot, “Working with radio modems.” 2005.
4. MaxStream, “Xtend Wireless OEM RF Module.” 2006.
http://maxstream.net/products/xtend/product-manual_XTend_PKG-R_rs-232-rs-485-RFModem.pdf
5. O.S. Engines, “61FX Owner’s Instruction Manual.” 2001.
6. SIG, “Kadet Senior ARF Assembly Manual.” 2002.
7. Multiplex, “Royal EVO Instructions.” 2002.
8. Multiplex, “Operating Instructions RX-9 / RX-12 SYNTH DS IPD receivers.”
9. Ublox TIM-LP Product Summary http://www.ublox.com/products/Product_Summaries/TIM-LP_Prod_Summary(GPS.G3-MS302028).pd
10. Reactive Technologies- James T. Francis.
11. North Carolina State University- Dan Edwards.
12. EMS Jomar, http://www.emsjomar.com/SearchResult.aspx?CategoryID=4 , 2006
13. Omoragbon, A., Watters, B., and Rahimi, S., “2011 AUVSI Student UAS Competition
Journal Paper,” University of Texas at Arlington, May 2008
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