A method and apparatus for identifying inertial reference unit (IRU) errors in a guided missile employing a multi-mode guidance system and constructing correction terms to recover the missile true position. Discrepancy parameters are introduced to indicate misalignment between missile and launching platform...http://www.google.com/patents/US4783744?utm_source=gb-gplus-sharePatent US4783744 - Self-adaptive IRU correction loop design interfacing with the target state estimator for multi-mode terminal handoff
