Assay devices, kits, and methods for detection of one or more analytes in a sample are provided. Within the enclosure of the pit beneath the surface across which the aircraft travel a counterweight system is connected by gears to pit lid supporting arms. The buoyant body and the reel housing are deployed from and towed at from a submerged platform. When the rotor is rotated, the camera also makes a circular movement on the plane of rotation. A motion vector is then estimated using the shifted vertical search range.