| The Large Adaptive Reflector is a Canadian design for a new radio telescope. The receiver is held at the focus of the reflector by an aerostat tethered to the ground by multiple tethers. One of the main goals in the design of this system is the minimization of the motion of the receiver. Most perturbations are produced by the action of the wind on the aerostat and transmitted to the confluence point via the leash that connects the aerostat to the receiver. For that reason, this work focused on leash-related stabilization techniques. Computer simulations were used to evaluate the benefits of different passive and active methods. Among the passive approaches studied were the use of a constant force spring and of a passive heave compensator. The active methods evaluated included aerostat pitch control and active heave compensation. One of the more promising approaches, a leash made of bungee cable, was evaluated experimentally on a prototype of the system in Penticton, BC. Finally, a pitch control mechanism was designed. This mechanism displaces the leash attachment point on the harness to pitch the aerostat nose up or down. |
