A general symmetry-preserving observer for aided attitude heading reference systems

International audienceWe generalize several recent works on nonlinear observers for aided attitude heading reference systems: we propose a symmetry-preserving nonlinear observer which merges the most common measurements available on an aircraft (altitude, Earth-fixed and body-fixed velocity, inertial and magnetic sensors). It can be seen as an alternative to the Extended Kalman Filter, but easier to tune and computationally much more economic. Moreover it has by design a nice geometrical structure appealing from an engineering viewpoint. We illustrate its good performance on simulation and experimental results

Generalized Multiplicative Extended Kalman Filter for Aided Attitude and Heading Reference System

International audienceIn this paper, we propose a “Generalized Multiplicative Extended Kalman Filter” (GMEKF) to estimate the position and velocity vectors and the orientation of a flying rigid body, using measurements from lowcost Earth-fixed position and velocity, inertial and magnetic sensors. Thanks to well-chosen state and output errors, the gains and covariance equations converge to constant values on a much bigger set of trajectories than equilibrium points as it is the case for the standard Multiplicative Extended Kalman Filter (MEKF). We recover thus the fundamental properties of the Kalman filter in the linear case, especially the convergence and optimality properties, for a large set of trajectories, and it should result in a better convergence of the estimation. We illustrate the good performance and the nice properties of the GMEKF on simulation and on experimental comparisons with a commercial system