A Nonlinear Observer for Air-Velocity and Attitude Estimation Using Pitot and Barometric Measurements

This paper addresses the problem of estimating air velocity and full attitude for unmanned aerial vehicles (UAVs) in GNSS-denied environments using minimal onboard sensing-an interesting and practically relevant challenge for UAV navigation. The contribution of the paper is twofold: (i) an observability analysis establishing the conditions for uniform observability, which are useful for trajectory planning and motion control of the UAV; and (ii) the design of a nonlinear observer on SO3R3R that incorporates pitot-tube, barometric altitude, and magnetometer measurements as outputs, with IMU data used as inputs, within a unified framework. Simulation results are presented to confirm the convergence and robustness of the proposed design, including under minimally excited trajectories.