Aircraft trajectory tracking with large sideslip angles for sense and avoid intruder state estimation

This paper deals with the problem of trajectory tracking and definition in monocular vision based sense and avoid scenarios for small UAVs where the intruder aerial vehicle should be held in camera field of view. After defining effective field of view (EFOV) and introducing its possible calculation tracking of a triangular waveform trajectory by a conventional roll angle based tracker is examined. This results in zero EFOV and so probably impossible sensing and avoidance. In the next step the authors propose a new tracking solution which uses large sideslip angles to hold aircraft roll angle around zero. This way an acceptable EFOV can be provided. Further improvements in EFOV are gained through the definition of a sinusoidal trajectory which gives smoother tracking. All the results are demonstrated with software-in-the-loop simulation data.