The vast ocean, which accounts for 70% of the Earth’s surface area, contains abundant minerals, energy, and biological resources, and surveys have been conducted in various ocean areas in recent years. It is extremely difficult for humans to conduct direct underwater surveys. Autonomous underwater vehicles (AUV) are expected to serve as platforms for surveying marine resources widely distributed throughout the vast ocean. However, owing to disturbances such as tidal currents, AUVs are unable to control there position well, making waypoint tracking difficult and preventing the observation of targeted observation points. In this research, to improve the robustness of AUVs in a tidal environment, we design a disturbance observer that estimates tidal currents as disturbances, and estimate tidal currents based on the results of actual diving surveys in actual sea areas using AUVs.

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