  We present a model-based approach to wind velocity profiling using motion
perturbations of a multirotor unmanned aircraft system (UAS) in both hovering
and steady ascending flight. A state estimation framework was adapted to a set
of closed-loop rigid body models identified for an off-the-shelf quadrotor. The
quadrotor models used for wind estimation were characterized for hovering and
steady ascending flight conditions ranging between 0 and 2 m/s. The closed-loop
models were obtained using system identification algorithms to determine model
structures and estimate model parameters. The wind measurement method was
validated experimentally above the Virginia Tech Kentland Experimental Aircraft
Systems Laboratory by comparing quadrotor and independent sensor measurements
from a sonic anemometer and two SoDARs. Comparison results demonstrated
quadrotor wind estimation in close agreement with the independent wind velocity
measurements. Wind velocity profiles were difficult to validate using
time-synchronized SoDAR measurements, however. Analysis of the noise intensity
and signal-to-noise ratio of the SoDARs proved that close-proximity quadrotor
operations can corrupt wind measurement from SoDARs.
