A Distributed Protocol for Multi-hop Underwater Robot Positioning

This paper presents a distributed protocol for multi-hop robot positioning in underwater environment without relying on GPS data at each robot. It is a complementary approach for localization and coordination estimations in underwater scenarios where GPS services are unavailable, unstable, or unreliable. The protocol conducts the positioning task in three phases periodically: distance estimating, positioning, and refining. Issues caused by alias problems and measurement errors are discussed and solved in order to improve the practicability of the approach and its accuracy of the location and coordinates estimations. Simulation results comparing to those by the existing work show that our research contributes: (i) a distributed multi-hop positioning algorithm and an associated protocol for underwater multi-hop robot networks; (ii) solutions to two practical issues that increase the practicability of the protocol; and (iii) investigations on relationships between network density, network scale, positionability, and positioning accuracy