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.