The invention relates to a method for estimating the spatial orientation of an object at a moment k using the global acceleration (yA), magnetic field (yM), and rotation speed (yG) measurements of said object along three spatial axes, and which comprises: A- the pre-processing (200) of said measurements (yA, yM> yG) at a moment k for detecting the existence of an interference in said measurements and estimating interference-free measurements at the moment k; B- the estimation of the orientation (formula (I)) at the moment k by an observer from the interference-free measurements (formula (II)) at the moment k resulting from step A.