纬度未知条件下捷联惯导摇摆基座自对准方法

Self-alignment algorithm for swaying SINS under geographic latitude uncertainty

中文关键词  捷联惯导系统  摇摆基座  自对准  纬度未知  特征值分解  重力表观运动

英文关键词  strapdown inertial navigation system  swaying base  self-alignment  latitude uncertainty  eigenvalue decomposition  gravity apparent motion

中文摘要

      针对纬度未知条件下捷联惯导摇摆基座自对准问题, 本文将其看作基于特征值分解的优化问题处理, 提出 一种基于地球系重力矢量的摇摆基座自对准方法. 首先, 构建基于速度增量形式的目标函数, 建立不依赖外部纬度 信息的地球系下重力矢量模型, 以提高地球系下重力矢量的估计精度; 然后, 将摇摆基座自对准看作Wahba姿态确 定问题, 基于地球系下重力矢量建立关于惯性系转换四元数的速度增量式目标函数, 增强对噪声及振荡干扰的抑 制, 利用基于特征值分解的多矢量优化方法完成摇摆基座自对准, 以提高对准精度; 最后, 通过设置捷联惯导摇摆基 座初始对准仿真及船舶系泊实验, 验证了所提方法的有效性.

英文摘要

      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 selfalignment 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 decompositionbased 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.