Thomas C. Furfaro

Building location awareness into acoustic communication links and networks through channel delay estimation

This paper examines range-based localization techniques for single and multiple high-frequency underwater acoustic sources, such as those used in underwater communication systems. The emphasis is on developing flexible methods that accept range data from different origins and assimilate them into desired position estimates using compact optimization-based formulations that can scale to large problem sizes and require little or no prior information on the geometries of the acoustic links. The paper discusses how multipath information can be used for single-source localization, and how pairwise range measurements between network nodes can be used to jointly recover their relative positions through factorization of Euclidean distance matrices.

Moving JANUS forward: A look into the future of underwater communications interoperability

In the past 8 years, the Centre for Maritime Research and Experimentation (CMRE) has developed, tested and promoted JANUS - a robust and simple modulation and coding scheme to be used as the first standard to support interoperability in digital underwater communications. This document aims at reporting the current status of JANUS and a first look at possible routes for evolution of this soon-to-be standard.

Supporting AUV localisation through next generation underwater acoustic networks: Results from the field

This work describes how the localisation of autonomous underwater vehicles can be supported through networked acoustic communication. The localisation approach includes timing information within acoustic messages to create an interrogation scheme similar to that of long-baseline methods, but realised at the application level of the network. In this way, the network itself is able to provide vehicle localisation information, reducing the needs for additional on-board sensors or dedicated deployed platforms/transponders. The aim of this work is to report at sea localisation results as obtained in two completely different application scenarios. The first one is represented by the FP7 MORPH project (HORTA15 sea trial) where the proposed approach has been applied to support navigation of a fleet of AUVs in a tight formation and in very shallow waters. The second application is represented by the NATO STO CMRE multistatic network demonstrator with the acoustic network used to support navigation of AUVs working in large operational areas. In this latter case, results are given from the COLLAB-NGAS14 experimental campaign.

A communications and relative navigation architecture for underwater vehicle coordination

This paper presents an implementation of a communications stack for underwater communications and relative localisation. The application scenario, under the auspices of the EC MORPH project, is described. The high-level architecture is described, with the relevant hardware and software implementation details. A summary of the localisation methods, based on previous works, is given, followed by a discussion of the encoding mechanism.

Micro-bathymetry data acquisition for 3D reconstruction of objects on the sea floor

This paper describes an effort to capture micro-bathymetry data for the end purpose of 3D object reconstruction, using an AUV-borne multibeam echo sounder. Due to the combination of relatively narrow across-track coverage and the navigation error of the vehicle, there is little guarantee that a single-pass scan will capture the target fully. A mission planning approach will be presented, with the goal of balancing mission duration and coverage. This method was demonstrated during a sea campaign in 2016 where multiple views of targets laying on the sea floor were acquired with the goal of developing a Target Registration System.