US Patent 11440680 Tether management system for a tethered UAV

A UAV tether management system comprising: a tether-wound spool rotatably mounted on a base station, a free-pivoting angle arm, and an angle arm encoder, wherein the tether is configured to transfer power from the base station to the UAV while the UAV is in flight, and the angle arm comprises a tether guide mounted to a proximal end of the angle arm such that the tether passes through the tether guide as the tether pays out of, or is taken up by, the spool, wherein the angle arm further comprises a counter weight mounted to a distal end of the angle arm such that a center of mass of the angle arm is aligned with the spool's axis of rotation, and wherein the angle arm encoder is configured to measure an offset angle of the angle arm.