A method and system for positioning in an underwater environment

Abstract

This application relates to the field of underwater robot navigation and environmental perception technology, and discloses a positioning method and system for underwater environments. The positioning method includes: acquiring flow velocity profile data, temperature data, salinity data, and depth data at sampling points; obtaining normalized flow field feature vectors and physical feature vectors corresponding to each sampling point; calculating the cosine similarity of the normalized flow field feature vectors and the physical feature similarity of the normalized three-dimensional physical feature vectors; weightedly fusing the cosine similarity and physical feature similarity to obtain a fusion similarity; combining the fusion similarity with preset constraint rules to obtain position revisit constraint factors; adding the position revisit constraint factors to the factor graph to construct a complete factor graph model; and using the iSAM2 algorithm to solve the factor graph to obtain the globally optimized position sequence of the underwater vehicle. This method can correct cumulative drift errors and effectively ensure the reliability of the AUV's trajectory in visually and acoustically limited scenarios.

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