Autonomous Fixed-Wing UAV Liam Cawley

Overview

I built and flew a 1.6 m MFD Crosswind Mini with autonomous takeoff and waypoint navigation. The aircraft integrated a Pixhawk Cube Orange running ArduPilot, RTK GPS, telemetry, and a camera payload. The work included airframe integration, state-estimation and control tuning, and an object-detection pipeline using YOLOv5 with Sony A6000 imagery.

The AUVSI SUAS 2021 mission supplied design requirements: a four-mile waypoint course, imaging roughly 250,000 m², identifying ground targets, and delivering a payload within a 40-minute mission budget. Those figures describe the target mission. They are not measured endurance or mapping performance for this aircraft.

The linked report describes an earlier 1.9 m Crosswind/Nimbus Pro design. Its component estimates and Keras letter-classifier proposal should be distinguished from the later Mini build. The report now opens with corrections to those distinctions and to several unsupported engineering claims.

The MFD Crosswind Mini airframe used for the build.

Design Decisions

Airframe integration. The flight controller, power distribution, radio equipment, and camera payload had to fit within the foam fuselage while leaving access for wiring and maintenance. The earlier design's 6.2 cm center-of-gravity target belongs to its larger airframe; it is not a measured balance specification for the Mini.

Navigation. ArduPilot handled the waypoint mission and flight-control loops. The build used EKF3 state estimation and PID/TECS control tuning, with telemetry available at the ground station. Autonomous flights demonstrated the takeoff and waypoint functions; the record does not provide a measured waypoint-error distribution or endurance curve.

Ground control station bench test — Ground-station bench setup with the flight controller, GPS, receiver, and telemetry hardware connected.

Imaging. The camera payload combined a video view with high-resolution imagery. The later object-detection work used YOLOv5 and Sony A6000 images. The earlier report's two-camera triggering scheme was a design description; it does not supply measured detection accuracy, imaging throughput, or geolocation error.

Hand-drawn power and signal wiring diagram — The wiring plan separates power rails, flight-control connections, telemetry, and video links.

Corrections to the design record

The report proposed a parachute-delivered LaTrax Teton ground vehicle and obstacle-avoidance work on a companion computer. It contains no drop-test results, demonstrated self-righting mechanism, or completed competition score. These remain proposed mission components in that document.

Several technical statements also needed correction. Motor $K_v$ is measured in rpm per volt. The quoted current calculation used a different motor and propeller from the selected design, and cannot establish its endurance. Image geolocation requires camera geometry and aircraft pose and altitude; elapsed time along a flight path alone is insufficient. A SUAS competition demonstration also does not confer federal “level-5 autonomy” certification.

Integration photographs

Airframe interior during integration — Airframe integration with the fuselage open and the wing sections detached.

Assembled aircraft during preflight setup — The assembled aircraft connected to the ground station for parameter checks.

The report retains the original design after the correction note, so the distinction between the proposal and the later build remains visible.