Multi-UUVs Cooperative Localization in Asymmetric Large Configuration

Multi-Underwater unmanned vehicles (UUVs) can make up for the defects of a single platform with the advantages of low cost, small size and large number, achieve the extension of time-space benchmark of the global navigation satellite system, and complete large-scale underwater search and rescue, submarine resource exploration, coordinated attack and other difficult and highly complex tasks. Aiming at the problem that the former work focuses on the symmetric configuration of single slave UUV and the task requirements of multi-UUVs formation configuration, a novel multi-UUVs cooperative localization method in asymmetric large configuration is proposed. Based on the nonlinear Lie derivative theory, the relationship between the system observability and the rate of direction and distance between UUV in adjacent time is derived, and the variation rule of the UUVs cooperative localization in asymmetric configuration is demonstrated. By adjusting the cooperative communication strategy, the multi-UUVs cooperative localization method in asymmetric large configuration is established. The sound velocity profile in Nankai trough (Japan) is selected, and multi-UUVs on the underwater and surface are simulated for verification. The experimental results show that the proposed method can significantly improve the accuracy of cooperative localization by increasing the underwater baseline constraint.