Pitot-Aided Attitude and Air Velocity Estimation with Almost Global Asymptotic Stability Guarantees

TL;DR

This paper presents a novel cascade observer for UAV attitude and air velocity estimation using IMU and Pitot tube data, providing almost global asymptotic stability guarantees and validated on real flight data.

Contribution

It introduces a new observer architecture with stability guarantees for UAV state estimation using minimal sensor data.

Findings

Achieves almost global asymptotic stability under mild conditions.

Demonstrates accurate estimation on real flight data.

Ensures uniform observability of the estimation error dynamics.

Abstract

This paper investigates the problem of attitude and air velocity estimation for fixed-wing unmanned aerial vehicles (UAVs) using IMU measurements and at least one Pitot tube measurement, with almost global asymptotic stability (AGAS) guarantees. A cascade observer architecture is developed, in which a Riccati/Kalman-type filter estimates the body-fixed frame air velocity and the vehicle's tilt using IMU data as inputs and Pitot measurements as outputs. Under mild excitation conditions, the resulting air velocity and tilt estimation error dynamics are shown to be uniformly observable. The estimated tilt is then combined with magnetometer measurements in a nonlinear observer on SO(3) to recover the full attitude. Rigorous analysis establishes AGAS of the overall cascade structure under the uniform observability (UO) condition. The effectiveness of the proposed approach is demonstrated through validation on real flight data.