Performance Characteristics of a Complete Vision Only Sense and Avoid System
Bálint Vanek, Tamás Péni, Ákos Zarándy, J. Bokor, Tamás Zsedrovits, Tamás Roska · 2012
The present paper investigates the real world feasibility of a purely vision based sense and avoid system, required for small unmanned aerial vehicles (UAV) to routinely access the national airspace.The two distinct functions, sensing and avoidance are integrated into a common framework.No information is exchanged between aircraft, only passive 2-D vision information is available to estimate the encountering traffic.Based on the predicted intruder motion the time of the encounter and the minimum distance are predicted.In case an intruder violates the minimum separation the onboard autopilot initiates an avoidance maneuver.The viability of the system is demonstrated on several estimation approaches, using Extended Kalman filter (EKF) and Unscented Kalman filter (UKF) implementations.Since it is shown that for certain type of observer movements the estimation process remains unobservable in bearings-only problems, the sensitivity of the estimation performance and the resulting avoidance response with respect to different intruder motion is investigated in a Monte-Carlo simulation.The system is tested on a high fidelity Hardwarein-the-Loop (HIL) simulation platform, where flight control algorithms, scene rendering, image processing and estimation algorithms are implemented individually over a network of computers with special emphasis on parallel implementation of computationally intensive tasks.Representative encounter scenarios are presented to provide performance measures, including detection time and achieved miss distance of distinctive approaches to assess the applicability of the results.