GNSS (Global Navigation Satellite System) positioning is not available underwater due to the very short range of electromagnetic waves in the sea water medium. In this article a LBL (Long Base Line) acoustic repeater system of the GNSS positioning is presented. The system is hyperbolic, i.e., based on time differences and it does not need very accurate atomic clocks to synchronize repeaters.
@article{arxiv.2204.08255,
title = {LBL System for Underwater Acoustic Positioning: Concept and Equations},
author = {Pablo Otero and Álvaro Hernández-Romero and Miguel-Ángel Luque-Nieto},
journal= {arXiv preprint arXiv:2204.08255},
year = {2022}
}