External force estimation for ARWs

This chapter focuses on estimating external forces applied to the ARWs, like wind gusts or variation in the center of gravity due to payload handling. To deploy ARWs in real-world applications, there is a need for online methods to compensate for external disturbances and uncertainties in localization. Optimally, in such scenarios, it is preferred to avoid a) equipping the ARW with extra sensors that directly affect the flight time; b) relying on system identification techniques to obtain parameters for the ARW aerodynamic models; c) relying on external sensors in the environment, such as weather station measurements. This chapter will present a method to estimate external forces and filter the ARW states thus reducing the noise affecting the states of an ARW. To compensate for the forces acting on the ARW, we utilize an augmented version of the nonlinear dynamic model of the system described in Chapter 3 and the equivalent NMPC defined in Chapter 4.