The University of Texas at ArlingtonAutonomous Vehicles Laboratory

2011 AUVSI Student UAS Competition Journal PaperSubmitted: May 23, 2011Student TeamDaniel Glowicz, Jonathan Efinger, Mariah Bacchus, Martin Dickson, Nicholas Yokell

FacultyDr. Atilla Dogan - Mechanical and Aerospace EngineeringDr. Brian Huff - Industrial & Manufacturing Systems EngineeringDr. Kamesh Subbarao - Mechanical and Aerospace EngineeringAbstract: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.

IntroductionDuring 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), systems design, expected performance and results as well as safety considerations made in effort to succeed in the mission.Mission RequirementsThe mission requirements, as specified in the competition rules, have five major parts which are summarized in the table below.Table 21: Key Performance Parameters (From 2011 AUVSI SUAS Rules)ParameterThresholdObjective

AutonomyDuring way point navigation and area search. All phases of flight, including takeoff and landing

ImageryIdentify any two target characteristics: Shape Background color Orientation Alphanumeric Alphanumeric color Identify all five target characteristics

Target LocationDetermine target location ddd.mm.ssss within 250 ft Determine target location within 50 ft

Mission timeLess than 40 minutes total Imagery/location/identification provided at mission conclusion 20 minutes Imagery/location/identification provided in real time

In-flight re-taskingAdd a fly to way pointAdjust search area

MethodologyIn 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. Project Chartering System Requirement Review Baseline Design Conceptual Design Feasibility Studies Preliminary Design Detailed Design Unit Testing Integrated Testing System Tuning and RehearsalsProject CharteringA charter for this project was issued on August 31, 2010. This document formally authorized the teams 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.System Requirements ReviewA 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.Table 51: System Requirement SummaryCapability LevelCapability

ThresholdAdd a fly-to waypoint

ThresholdChange altitude while in automatic mode

ThresholdChange airspeed while in automatic mode

ThresholdAutomatically fly waypoints

ThresholdAutomatically fly search area

ThresholdView 60 degrees in every direction vertically below the air vehicle

ThresholdPrint 2/5 target characteristics at conclusion

ThresholdPrint target location within 250 at conclusion

ThresholdConclude within 40 minutes

ThresholdAddress Safety issues

ObjectiveAutomatically take off

ObjectiveAdjust the search area and display the changes

ObjectiveDisplay/Print 2/5 target characteristics during flight

ObjectiveDisplay/Print 5/5 target characteristics during flight

ObjectiveDisplay/Print target location within 250 during flight

ObjectiveDisplay/Print target location within 50 during flight

ObjectiveAutomatically land

ObjectivePrint 5/5 target characteristics at mission conclusion

ObjectivePrint target location within 50 at mission conclusion

ObjectiveConclude at 20 minutes

StretchPrint 4/5 enroute-off-flight-path target info at mission conclusion

StretchDisplay new search area (for Pop Up target) during flight

StretchPrint Pop Up target image & location within 250 at mission conclusion

StretchAutomatically id/cue >= 2 targets with >= 50% correct

StretchJAUS Compliance

Baseline DesignThe 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 controllerA 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 Indifference or unknown: 0 Weakness: -1The table below shows the figure of merit for aircraft selection.Table 61: Air Vehicle Figure of MeritsMeritsW. F.BlimpFixed Wing PropTilt rotorHelicopterFixed Wing Jet

Payload Volume to vehicle weight ratio4-11 1 -11

Cost of parts4-10 -1-1-1

Legacy30 1 0 0 0

Ease of implementation3-11 -1-10

Compatibility with auto Controller50 1 -10 0

Speed3-11 1 -11

Maneuverability in search Area31 0 1 1 -1

Piloting experience50 1 -10 -1

Product Total-1123 -7-11-5

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. Table 62: Vehicle Configuration Figure of MeritsMeritsW. F.MicroPilotPiccoloKestrelStargate

Cost41 -1-11

Experience with it51 0 0 -1

Package41 1 1 0

Accessibility31 0 0 -1

Flexibility30 0 1 1

Meets all autonomous objectives51 1 0 -1

Product Total21 5 3 -6

The MicroPilot solution was chosen because it was the most cost effective choice as the team already possesses two systems. Additionally, the team has about five years of experience with MicroPilot and has performed well in two UAV competitions using it.Conceptual Design and Feasibility StudiesSince 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 MultiplexerThe 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.Table 71: Conceptual Design Figure of MeritsMeritsW. F.Single Fixed CamMP Stabilized CameraIn House Stabilized CameraMultiple Fixed Cameras

Overall Risk31 0 -1-1

Incremental Development41 0 -1-1

Reliability41 0 0 -1

Available Resources 30 0 0 -1

Our Experience 41 1 -1-1

HW Complexity 31 0 -1-1

Weight4-11 -1-1

Cost4-10 0 -1

Flexibility4-11 1 1

Ingenuity2-11 1 1

Product Total4 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.Preliminary DesignDuring 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.

Imaging Station Pilot Aircraft ServosSafety SwitchSwitchRadio ModemR/C RXVideo TXGround Control Station

GroundControlStationRadio ModemTeam LiaisonJudgesVideo RX Imaging LaptopR/C TXData LinkAirAutonomous Imaging ProcessingJoystickLeft AileronRight AileronElevatorRudderThrottleRollPitchStabilizedMountGround

GroundMicroPilotVideo LinkOEM Camera

Figure 81: System diagramThe overall system can be divided into the airframe, radio control, autonomous control, imaging, communication and power subsystems.Airframe SubsystemThe 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 HS-645BB 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 82: Three-view drawing of the SIG Kadet Senior (picture from ARF Manual)

Journal Article: 2011 AUVSI Student UAS Competition

University of Texas at Arlington Autonomous Vehicles Lab Page 1 of 20Table 81: Airframe CharacteristicsAspect Ratio5.07

Wing Area (ft2)7.92

Wing Span (ft)6.33

W/S (lb/ft2)0.66

Fuselage Length (ft)5.33

Fuselage Width (ft)0.42

Weight Take-Off (lbs)12

Weight Landing (lbs)11.5

Table 82: Engine SpecificationsEngine Model.91 FX (OSMG0591)

Displacement (cu in)0.912

Bore (in)1.091

Stroke (in)0.976

RPM2,000 -16,000

Output (hp @ rpm)2.80 @ 15,000

Weight (oz)19.42

Recommended Props15x8, 16x6

Radio Control SubsystemThe 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.

Figure 83: Radio Control Subsystem diagramGlitch 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.

Figure 84: Jomar Electronics Glitch buster (from http://www.emsjomar.com/)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 pilots 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 85: Reactive Technologies Safety Switch (from http://www.reactivetechnologies.com/RxMux.html)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 pilots 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 pilots transmitter.

Figure 86: R/C Receiver (from http://www.multiplexusa.com/)Pilots R/C Transmitter:The pilots transmitter is the means by which the pilot can control the airplane. This transmitter sends signals to the air vehicles 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 87: 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 malfunctionAutonomous Control SubsystemThe 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. The Autonomous subsystem comprises of the MP2028g board, its sensors and Ground Control Station softwareMP2028g 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 88: 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 Roll2. Elevator from Desired Pitch3. Rudder from Y-accelerometer 4. Rudder from Heading 5. Throttle from Speed 6. Throttle from Glide Slope 7. Pitch from Altitude8. Pitch from AGL Altitude9. Pitch from Airspeed Altitude10. Roll from Heading 11. Heading from Cross Track12. Pitch from DescentGround 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.

Figure 89: A screen shot of the GCS HORIZON Software GUIThe GCS also has a window which displays the cameras projection and gives the camera center location in UTM coordinates. A picture of this widow is shown below.

Figure 810: A screen shot of the Camera Status window showing camera center locationImaging SubsystemThe 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.

Figure 811: Imaging subsystem diagramRoll-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 planes 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 812: Roll-Pitch gimbaled cameraImage 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.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 813: Pictures of triangles automatically detected by the imaging programCommunication SubsystemThe 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 814: Radio Modem, Video Transmitter and Diversity ReceiverPower SubsystemA 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.

Figure 815: Power distribution schematicUnit TestingAll 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.Detailed DesignDuring 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.Aircraft LayoutEach 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 101: Power, autonomous and R/C subsystems and an Alden PL700 connectorTarget Search Pattern and Target identification ProcedureA search needs to be performed that will maximize the use of the gimbaled camera and MicroPilots capabilities in accomplishing the mission. A figure of the selected search pattern is shown in Figure 102 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.

Figure 102: Target Search PatternOperator 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 Operators computer.7. The Camera Operators 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 Operators computer spools the print job without further manual intervention.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.Target Editors Loop:1. The printer prints the Camera Operators image.2. The printer prints the Horizon Operators 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 cameras 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 judgesIntegration TestingIntegration 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.Safety FeaturesSafety 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.Procedures for Accident AvoidanceThe general operation guidelines are: 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 airplanes 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.Hardware Handling 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 engines 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 oneSafety Devices 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 detailsConclusionMany 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 Arlingtons Autonomous Vehicles Labs 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.AcknowledgementsWe 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.References1. MicroPilot, MP2028g - Autopilot.2005, http://www.micropilot.com/Manual-MP2028.pdf2. 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-RF-Modem.pdf5. O.S. Engines, 61FX Owners 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.u-blox.com/products/Product_Summaries/TIM-LP_Prod_Summary(GPS.G3-MS3-02028).pd10. Reactive Technologies- James T. Francis.11. North Carolina State University- Dan Edwards.12. EMS Jomar, http://www.emsjomar.com/SearchResult.aspx?CategoryID=4 , 200613. Omoragbon, A., Watters, B., and Rahimi, S., 2011 AUVSI Student UAS Competition Journal Paper, University of Texas at Arlington, May 2008