Study of a Multitethered Aerostat System: Experimental Observations and Model Validation

Abstract

An aerial positioning system is proposed using a helium aerostat and a series of tethers attached to the ground. The system is intended to position the receiver for a large-scale radio telescope. An experimental tritethered system was developed to evaluate the behavior of the system and provide a basis for comparisons with a previously developed dynamics model. The dynamics model combines discretized lumped-mass tether models, an aerodynamic model of the aerostat and a turbulent wind model. Results from four test flights at different geometrical configurations are presented. The tritethered aerostat system exhibited impressive performance, as the payload motion was 2 orders of magnitude smaller than the aerostat motion. Validation of the dynamics model was achieved through a two-stage process. In the first step, the tether model was verified independently of the aerostat and wind models. Once the fidelity of the tether model was established, simulation results for the full dynamics model were compared to experimental results and the model proved to be effective for predicting the statistics of the motion of the system.