Formation geometry of underwater positioning based on multiple USV/AUV

Aiming at the shortcomings of existing underwater high precision positioning technologies for the autonomous underwater vehicle (AUV), an underwater positioning system based on the unmanned surface vehicle (USV) is designed using the intelligent buoys technology and the moving long baseline technology of the global positioning system. An evaluation function is established on the knowledge of the Cramer-Rao lower bound and the Fisher information matrix. The influence of the relative formation geometries of the USV/USV and USV/AUV on the positioning performance is analyzed by maximization of the evaluation function in three-dimension. Subsequently, the sensitivity of the positioning performance to small distance deviations and small angle deviations from the optimal geometry is investigated. Finally, simulation results show the effectiveness of the function and the system.