纬度未知条件下捷联惯导摇摆基座自对准方法

Aimed at solving the initial alignment problem of swaying strapdown inertial navigation system (SINS) under geographic latitude uncertainty, which is considered as an eigenvalue decomposition optimization-based alignment problem in the paper, a self-alignment algorithm based on the gravity vector in earth frame is proposed. Firstly, the velocity increment-based objective function is constructed to represent the gravity vector in earth frame without the aid of external latitude information, which can improve the estimation accuracy of the gravity vector in earth frame. Secondly, the self-alignment of swaying SINS is transformed into a Wahba problem and the gravity vector-based objective function in velocity increment form is built to restrain the disturbances of the sensor noises and oscillations. Then the eigenvalue decomposition-based optimization method is employed to determine the accurate attitude quaternion on the swaying base. Finally, both simulations and ship mooring experiment under the swaying base are carried out, and the results verify the effectiveness and superiority of the proposed algorithm under geographic latitude uncertainty.