System identification of High Altitude Long Endurance fixed-wing aerial vehicles is challenging as its operating flight envelope covers wide ranges of altitudes and Mach numbers. We present a new global system identification framework geared towards such fixed-wing aerial platforms where the aim is to build a global aerodynamic model without many repetitions of local system identification procedures or the use of any aerodynamic database. Instead we apply parameter identification techniques to virtually created system identification data and update the identified parameters with available flight test data. The proposed framework was evaluated using data set outside the flight envelope of the available flight test data, i.e. at different airspeeds considering both interpolation and extrapolation scenarios. The error analysis has shown that the obtained longitudinal aerodynamic model can accurately predict the pitch rate and pitch angle, mostly within a tolerance of +1.5 degrees/s and +2 degrees respectively. Such a cost and time efficient model development framework enables high fidelity simulation and precise control which ultimately leads to higher success rates in autonomous missions.

Within this paper, a new fast algorithm that provides efficient solutions to the problem of inspection path planning for complex 3D structures is presented. The algorithm assumes a triangular mesh representation of the structure and employs an alternating two-step optimization paradigm to find good viewpoints that together provide full coverage and a connecting path that has low cost. In every iteration, the viewpoints are chosen such that the connection cost is reduced and, subsequently, the tour is optimized. Vehicle and sensor limitations are respected within both steps. Sample implementations are provided for rotorcraft and fixed-wing unmanned aerial systems. The resulting algorithm characteristics are evaluated using simulation studies as well as multiple real-world experimental test-cases with both vehicle types.

This paper presents the conceptual design, detailed development and flight testing of AtlantikSolar, a 5.6m-wingspan solar-powered Low-Altitude Long-Endurance (LALE) Unmanned Aerial Vehicle (UAV) designed and built at ETH Zurich. The UAV is required to provide perpetual endurance at a geographic latitude of 45°N in a 4-month window centered around June 21st. An improved conceptual design method is presented and applied to maximize the perpetual flight robustness with respect to local meteorological disturbances such as clouds or winds. Airframe, avionics hardware, state estimation and control method development for autonomous flight operations are described. Flight test results include a 12-hour flight relying solely on batteries to replicate night-flight conditions. In addition, we present flight results from Search-And-Rescue field trials where a camera and processing pod were mounted on the aircraft to create high-fidelity 3D-maps of a simulated disaster area.