Separate-bias quaternion estimation of SINS alignment under large initial heading error

This paper presents a new separate-bias quaternion estimation algorithm for SINS alignment under large initial heading error. Surface and air launched weapons can inherit large heading errors during the initialization process by launch platform, which, if uncorrected, can inhibit terminal seeker acquisition of the target. To handle large heading error a new attitude error model is introduced and the error equations are established by additional quaternion error. In this algorithm iterative filtering with velocity measurement is used. In addition the computer simulation is carried out to validate the performance of the proposed algorithm. The simulation results indicate the quaternion errors decrease very quickly for a short term.