A Fast Initial In-movement Self-alignment Scheme Of Strapdown Inertial Navigation System Aided With Velocity And Position

Initial alignment is one of key technology of strapdown inertial navigation system(SINS), the performance of SINS is decided by the expeditiousness and accuracy of initial alignment. An optimal fast in-movement initial alignment scheme is proposed in this paper. The requirements of optimal in-movement initial alignment is acquired with the analysis about the factors affecting initial alignment and transformed into an optimization problem with constraint. This optimization problem is settled by an optimal initial alignment scheme which is carried out by backtracking and validated to be more rapider than traditional scheme by experiment.The main contents and work include the following aspects:(1)Different fine alignment models with different assistant information is formulated, and the expeditiousness and accuracy of fine alignment is investigated from the points of models, alignment-time, alignment-time assigning and position-error in the alignment which is base for putting forward the optimal alignment scheme.(2)According to the factors which affect the expeditiousness and accuracy of alignment, researching on fast initial alignment is transformed into an optimization problem with constraints which is settled to formulate the optimal in-movement backtracking alignment scheme.(3)According to different assistant information, different coarse and fine alignment schemes is formulated. The technology of implementing backtracking alignment is also investigated which includes inertial navigation algorithm in backtracking conditions, correcting position error which is caused in alignment process, compensation for velocity in low- frequency data storage condition.(4)utilizing the data of vehicle and UUV the efficiency of backtracking alignment algorithm is investigated form three aspects: the alignment accuracy, the position error of alignment accomplished instant is low which guarantee following high accuracy of navigation, the expeditiousness in the sight of accomplishing the navigation mission.(5)Three key technology is formulated to implement backtracking alignment algorithm which include inertial navigation algorithm in backtracking conditions, correcting position error which is caused in alignment process, compensation for velocity in low- frequency data storage condition.