Preliminary Study on System Design of USBL-Aided Underwater Navigation for Hull Cleaning Robots

Biofouling on ship hull should be removed for energy efficiency of ships in service, also for marine environmental protection against invasive aquatic species. Underwater navigation is one of the core technologies of hull cleaning robots (HCR), and it is essential for the intelligence and autonomy of the HCR. In this paper, we proposes a designed of an underwater navigation system for multiple HCRs using USBL acoustic positioning as an auxiliary sensor. Two USBL transceivers will be placed in the bow and stern respectively to measure four HCRs' position. The position measurement distortion of USBL caused by diffraction waves and the effect of reflection waves between the dock wall (or seabed) and docked ship will be discussed. This paper also proposes a method for correcting diffraction errors, judging and rejecting outliers.