Experimental Evaluation of Accuracy and Efficiency of Alternating Landmark Navigation by Multiple AUVs

This paper presents the experimental evaluation of the alternating landmark navigation (ALN) by multiple autonomous underwater vehicles (AUVs) using latest results of sea experiments and tank tests in terms of accuracy and efficiency. Self-localization is essential for AUV navigation, and AUVs are typically supported by long base line or super short base line of the support system. Against these methods, the ALN was proposed, where each AUV alternately becomes a landmark, which remains stationary on the seafloor, whereas the other AUVs can navigate based on acoustic positioning with the landmark AUV. The ALN realizes stable navigation without any support. Our goal is to realize surveying near the seafloor using only AUVs. The performance of the ALN in obstacle-existing environments was evaluated through the simulation to discuss the expandability of the ALN. The ALN was implemented on AUVs “Tri-Dog 1,” “Tri-TON,” and “Tri-TON 2.” On the basis of the sea experiments and the tank tests conducted with these AUVs, the performance of the ALN was verified. In particular, accuracy and efficiency of the ALN were evaluated through the tank test. Finally, it is shown that the ALN can realize accurate and efficient survey of the seafloor by only AUVs without any support.