Performance Enhancement Technique for Position-based Alignment Algorithm in AUV’s Navigation

This paper presents an improved approach for in-motion alignment based on position estimation to accurately determine the initial heading-angle of an autonomous underwater vehicle. The existing method for in-motion alignment is highly sensitive to errors from GPS reception and the localization algorithm, particularly in the vicinity of the starting point. Consequently, compensation values for the heading-angle obtained in the vicinity of the starting point are unreliable. To address this issue, this study analyzes the variance of the heading-angle compensation during the early stage of the alignment process, aiming to assess the reliability of the compensation value. By using variance as a criterion, the algorithm determines whether to continue the execution of the early stage in the alignment process. If the variance falls below a certain threshold, the algorithm calculates the correction value of the final heading-angle based on each correction value. The proposed algorithm is validated through practical experiments using sensor data collected from real-sea environments. The experimental results demonstrate an average improvement of 50.48% in localization performance with respect to the existing algorithm. Therefore, the proposed algorithm enhances the performance of the in-motion alignment algorithm.