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A local area UAS detection system from an elevated observation position

We present a new approach to an optical UAS detection system that confirms several requirements specified by the authorities. Our UAS detection system consists of a ground unit and a folding mirror located in the air. The ground based unit contains high resolution camera system mounted on a pan tilt unit. Therefore, the lens of the camera system can be actively aligned to a convex mirror which is located in vertical distance over the ground unit on the lower side of a raised captive balloon. The focal length of the ground based lens, the altitude of the balloon and the curvature of the mirror define the field of view towards the ground. The recorded video streams are processed in a vision system using change detection and other algorithms to alert a UAS intrusion. We will outline the design parameters of the optical system, the requirements and the implementation of the mechanical system as well as the active alignment system and show first results of outdoor operation