The in‐motion alignment for the underwater strapdown inertial navigation system is still a challenging problem due to various disturbances in the underwater environment. In this paper, a novel in‐motion alignment method, based on the Lie group representation, is developed. In this method, the process model is rewritten using the Lie group of the constant attitude matrix between two inertial frames as the state. An exact linear measurement model is constructed by analyzing the effect of the sensor errors in calculating the velocity vector. Next, the state‐dependent Lie group filter is designed basing on accurate derivation expressions for the covariance matrices of state‐dependent noises. The simulation and experiment results demonstrate that the proposed method can achieve better alignment accuracy and time than the existing method. The accuracy improves by 70% with the quaternion Kalman filter.

中文翻译：

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基于状态依赖李群滤波器的水下捷联惯导运动对准方法

由于水下环境中的各种干扰，水下捷联惯性导航系统的运动对准仍然是一个具有挑战性的问题。本文提出了一种基于李群表示的运动对齐方法。在该方法中，使用两个惯性框架之间的恒定姿态矩阵的李群作为状态来重写过程模型。通过分析传感器误差在计算速度矢量中的作用，构建了精确的线性测量模型。接下来，基于状态相关噪声的协方差矩阵的精确推导表达式，设计了状态相关的李群滤波器。仿真和实验结果表明，与现有方法相比，该方法具有更高的对准精度和时间。