A semi-global model-based state estimator for the quadrotor using only inertial measurements

We propose a nonlinear observer to estimate the state (orientation and in-plane velocity vector) of the quadrotor, based on a drag-force-enhanced model. It is an alternative to recent works using a similar model together with an Extended Kalman Filter (EKF). But while enjoying the benefits of an enhanced model, it does not have the usual drawbacks of an EKF: indeed, the computational cost is much lower, the tuning is easier, and above all the guaranteed domain of convergence is very large.