Nonlinear Dynamic Simulation of a Tethered Aerostat: A Fidelity Study

Full-scale flight tests of an instrumented TCOM 71M tethered aerostat conducted by the U.S. Army provide a database for determining the fidelity of the TCOM nonlinear dynamic simulation. Six global position system sensors, accurate to ±5 cm, determined the position and attitude of the aerostat, and winds were measured using a three-axis anemometer mounted on the aerostat's fin near the tip. A 32-min window of data was selected for comparison with the simulation, using the recorded winds to derive a turbulence table. This required correcting the winds for aerostat velocity and transforming to an Earth-fixed coordinate system aligned with the mean aerostat heading. Best results were obtained when the turbulence was propagated through the reference point with uniform flow over the aerostat, rather than the segmented hull with nonuniform flow