In this paper the problem of the speed estimation of an Unmanned Aerial Vehicle is addressed, when acceleration, the angles and the angular speeds are available for measurement. We focus our analysis on a prototype drone -a 4 rotors helicopter robot-which is not equipped with GPS related devices and relies on the Inertial Measurement Unit (IMU) only. A global exponential solution to this open problem is provided in the framework of adaptive observation theory when exact measurements are available. A modified estimator is presented to enhance robustness in velocity estimation in the realistic case of noisy acceleration measurements.

International audienceIn this article, the problem of robust state observer design for a class of unmanned aerial vehicles (UAVs) is addressed. A prototype four-rotors helicopter robot for indoors and outdoors applications is considered: the drone is not equipped with GPS related devices, so we describe a strategy to estimate its translational velocity vector based on acceleration, angles and angular speeds measurements only. Since the linearised system is non-observable at the equilibrium point, a nonlinear observability verification is performed for persistently exciting trajectories. A global exponential solution to this open problem is provided in the framework of adaptive observation theory when exact measurements are available. A modified observer is presented to enhance velocity estimation robustness in the realistic case of noisy measurements. The results are compared with a classical estimation strategy based on the extended Kalman filter to test the algorithm's performance

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