Sea experiments and tank tests on alternating landmark navigation using multiple AUVs: Towards accurate and efficient survey of seafloor by AUVs

This paper presents the latest results of sea experiments and tank tests on the navigation method for wide-area surveys of the seafloor using multiple autonomous underwater vehicles (AUVs). Each AUV alternately becomes a landmark, which remains stationary on the seafloor, while the other AUVs can navigate over a wide area with high positioning accuracy based on the landmark AUV. Unlike conventional navigation methods such as dead reckoning or inertial navigation, our method realizes stable navigation using only AUVs. Our goal is to realize surveying near the seafloor using only AUVs, without any surface aid. Alternating landmark navigation (ALN) is implemented with AUVs `Tri-Dog 1', `Tri-TON' and `Tri-TON 2'. On the basis of the sea experiments and tank tests conducted with these AUVs, the performance of ALN is verified.