Tether management system for a tethered UAV

An unmanned aerial vehicle (UAV) tether management system comprising:

• a spool having an axis of rotation and a slip ring, wherein the spool is configured to be rotatably mounted on a base station;
• a spool motor operatively coupled to the spool and configured to cause the spool to pay out or take up the tether;
• a tether wound on the spool, wherein the tether is configured to transfer power and communication signals between the base station to the UAV via the slip ring while the UAV is in flight;
• an angle arm assembly mounted to the spool such that the angle arm assembly is free to pivot around the axis of rotation, wherein the angle arm assembly comprises a pair of angle arms and a tether guide, wherein each angle arm has a proximal end and a distal end to which a counter weight is mounted such that a center of mass of the angle arm assembly is aligned with the axis of rotation, and wherein the tether guide is mounted between the proximal ends of the angle arms such that the tether passes through the tether guide as the tether pays out of, or is taken up by, the spool;
• and
• an angle arm encoder mounted to the spool and configured to measure an offset angle of the angle arm with respect to a reference plane that is parallel to the axis of rotation.