Abstract:The strap-down inertial unit is one of the core equipment of the navigation control system. It can perform independences detection, independences alignment, and independences calibration through a rotating mechanism. The establishment of the digital model of the strap-down inertial group is conducive to monitoring the product status, predicting the trend of product accuracy, and assisting in locating product faults. In this paper, the system composition of the strap-down inertial group is analyzed, and the corresponding mathematical model is established according to the characteristics of different components, and then the multi-dimensional and multidisciplinary dynamic model of the strap-down inertial group is established based on the digital twin, and finally, the model can be verified through experiments to consistently reflect the attributes, functions, performance and tested capabilities of the real product of the strap-down inertial group. Through the digital twin system of the strap-down inertial group, the real-time interactive application of the strap-down inertial group between the digital space and the physical space is realized.