Inertial navigation system aiding by passive seeker angle tracking

A novel inertial navigation system (INS) aiding approach is raised by exploring the possibility of using seeker bearings-only measurement in the missile midcourse guidance. INS error model was formulated, and line-of-sight (LOS) angles were solved. The error model of angle solution was derived, which was applied in Cramer-Rao lower bound derivation for the proposed INS aiding problem. A sequential square root Kalman filter was designed for the optimal INS error estimation. Simulation in typical trajectory was carried out to verify the aiding performance. A loosely coupled system was implemented to realize INS feedback augmentation in flight. Hardware-in-the-loop testbed is built for assessments and good performance is reported in the simulation test by using statistics of missile auto-control termination error.