An algorithm for determining the initial orientation of a strapped-down block of inertial elements mounted on a movable base

A method is proposed for determining the initial setting of the block of inertial elements of a strapped-down navigational system attached to a movable base. The algorithm, which uses additional information on the relative motion of the base, is sufficiently accurate and makes it possible to assess the instrument errors of strapped-down inertial navigation systems. Mathematical modeling indicates that the use of the algorithm proposed here in combination with optimal filtering makes it possible to reduce orientation errors to less than one angular minute for times from 10 to 100 s.