Accurate and Efficient Seafloor Observations With Multiple Autonomous Underwater Vehicles: Theory and Experiments in a Hydrothermal Vent Field

This letter reports the sea experiments of a navigation method for multiple autonomous underwater vehicles (AUVs) that relies on a single high-performance AUV, which can estimate its self-state (position and pose) accurately without any support. In the method, there isa parent AUV and child AUVs. While the latter have minimal navigational sensors, such as a microelectromechanical gyro, a single-axis fiber optic gyro and cameras, the former can estimate its self-state without any support using high-grade navigational sensors, such as an inertial navigation system and a Doppler velocity log. As all the AUVs have acoustic positioning and communication devices, the child AUVs can also estimate their self-state as accurately as the parent AUV; thanks to relative positioning with the parent AUV. We performed the sea experiments in a hydrothermal vent field using AUVs. Post-processing state estimation using sensor data from the experiments showed that the proposed method can realize long-distance navigation while maintaining an accuracy more than five times that for navigation independently performed by a child AUV.