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Cooperative navigation method of multiple autonomous underwater vehicles for wide seafloor survey — Sea experiment with two AUVs

In this paper, we report sea experiments using two AUVs on which the cooperative navigation method proposed in the previous report was implemented. The method divides vehicles into two groups: moving and landmark vehicles. A moving AUV estimates the states (horizontal positions and heading angle) from its ground velocity, horizontal angular velocity, and acoustical positioning relative to a landmark AUV remaining stationary on the seafloor. Each AUV can navigate over a wide area with small drift by alternating the landmark role. The proposed method is implemented on two actual AUVs (AUV Tri-Dog 1 and AUV Tri-TON). Both AUVs were evaluated in sea trials at Suruga Bay, Japan, in November 2013. The AUVs succeeded in a cooperative navigation, alternatively becoming the landmark. The performance of the method was verified through the sea experiments and post-processing simulation using the experimental results.