Design and implementation of a low-cost observer-based attitude and heading reference system

A nonlinear observer (i.e. a “filter”) is proposed for estimating the attitude of a flying rigid body, using measurements from low-cost inertial and magnetic sensors. It has by design a nice geometrical structure appealing from an engineering viewpoint; it is easy to tune, computationally very thrifty, and with guaranteed (at least local) convergence around every trajectory. Moreover it behaves sensibly in the presence of acceleration and magnetic disturbances.Experimental comparisons with a commercial device illustrate its good performance; an implementation on an 8-bit microcontroller with very limited processing power demonstrates its computational simplicity.