Fast Self-Alignment Technology for Hybrid Inertial Navigation Systems Based on a New Two-Position Analytic Method

Initial alignment technology is a key technology for inertial navigation systems (INSs) because the speed and accuracy of the initial alignment determine the working accuracy and rapid response capability of the INS. Thus, the initial alignment technique of an INS must be investigated. In a swaying base environment, traditional alignment methods cannot meet the requirements of alignment accuracy due to the occurrence of interference acceleration and angular velocity, and filtering methods do not perform well in practical and universal applications. This paper studies the self-alignment problem for the swaying base of a rotary strapdown inertial navigation system and uses the latest hybrid inertial navigation system (HINS) as the research platform. Using the double-position rotation strategy, a navigation algorithm based on an updated attitude transformation matrix and a dynamic error compensation algorithm are established, and they effectively resolve the fast and high-precision self-alignment problem of the rotary inertial navigation system (RINS) under the oscillating state. The accuracy and feasibility of the method are demonstrated by mathematical simulations. Experiments show that compared with traditional single-position and continuous-rotation alignment methods, the proposed dynamic self-alignment technology of HINS has the advantages of short alignment time, high alignment accuracy, and dynamic environment adaptability.