“…The arithmetic operations on the attitude and misalignment, including differentiation, integration, and covariance calculations required to implement KF methodology are not trivial since attitude does not belong in a linear space [ 9 , 10 , 11 ]. Attitude and misalignment belong to nonlinear spaces, such as the 3-dimensional special orthogonal group and 3-sphere space [ 12 , 13 ]. The research [ 14 , 15 ] used usual operations on attitude assuming that linear approximation does not cause a big problem.…”