A New Analytical Method to Improve Attitude Correction in Inertial Navigation Systems

Inertial Navigation Systems suffer from accumulative errors due to their dead reckoning structure. Consequently, the navigation reset or realigning process of such systems is unavoidable. Realigning starts with estimating the navigation errors and correcting the navigation states. To correct the error of attitude states in the navigation reset process, different kinds of attitude correction method are used in the literature. This paper proposed an analytical attitude correction method that can calculate the error of Euler angles more precisely than the conventional method. In addition, this new approach preserves normality and orthogonality characteristics of the transformation matrix while the conventional method leads to losing both of these conditions. The proposed method expresses the error of Euler angles as functions of Euler angles and small rotation angles. The relation between the Euler angles error and the small rotation angles is nonlinear and mathematical calculation is performed to extract the explicit functions. Numerical simulations prove that the proposed method of attitude correction has the mentioned features and its performance is dominant over the conventional method.