A Hybrid Underwater Acoustic and RF Localisation System for Enclosed Environments using Sensor Fusion

Underwater localisation systems are traditionally based on acoustic range estimation, which lacks the accuracy to localise small underwater vehicles in enclosed structured environments for mapping and surveying purposes. The high attenuation of electromagnetic waves underwater can be exploited to obtain a more precise distance estimation over short distances. This work proposes a cooperative localisation system that combines an acoustic absolute localisation system with peer-to-peer distance estimation based on electromagnetic radio frequency (RF) attenuation between multiple robots. The proposed system is able to improve the position estimation of a group of Autonomous Underwater Vehicles (AUVs) or Remote Operated Vehicles (ROVs) for exploring enclosed environments.