Network Of Underwater Vehicles Research Articles

An origin state method for communication constrained cooperative localization with robustness to packet loss

This paper reports on an exact, real-time solution for server–client cooperative localization over a faulty and extremely bandwidth-limited underwater communication channel. Our algorithm, termed the origin state method, enables a ‘server’ vehicle to broadcast its navigation information to multiple ‘client’ vehicles over a bandwidth-limited and faulty communication channel. The server’s broadcasted pose-graph can be used in conjunction with an estimator on the client to exactly reproduce the corresponding server–client centralized estimate. We present an evaluation over an extensive real-time field implementation of the proposed algorithm for a multi-agent autonomous underwater vehicle network using underwater acoustic modems to communicate in a synchronous-clock transmission framework.

Optimal Control of a Surface Vehicle to Improve Underwater Vehicle Network Connectivity

The use of an autonomous surface vehicle as an auxiliary agent to improve connectivity in a network of autonomous underwater vehicles is investigated. An algorithm is developed that consists of an optimal waypoint generator and a minimum-time guidance law that is used to steer the vehicle to the waypoint. This algorithm is used together with a communication architecture to improve underwater vehicle connectivity in a region of interest. The approach is simulated using various underwater vehicle configurations, both with and without the autonomous surface vehicle, where it is found that network connectivity is improved significantly via the inclusion of the autonomous surface vehicle. An in-water hardware test is then performed and is shown to be consistent with the simulation results. The results of this study show that adding an autonomous surface vehicle to an underwater vehicle network can improve the connectivity of the network.

An Origin State Method for Lossy Synchronous-clock Acoustic Navigation

This paper examines the problem of localizing a network of underwater vehicles using inter-vehicle range observations derived from measuring the one-way-travel-time (OWTT) of acoustic broadcasts. We report the derivation of the novel origin state method; an algorithm for distributing a local pose-graph as a sequence of minimal bandwidth information packets that is robust to packet loss. We demonstrate the effectiveness of this algorithm as an extension of the decentralized extended information filter (DEIF) for synchronous-clock acoustic navigation through post-process implementation using a real-world data set.

Autonomous underwater vehicle networks as integrated acoustic observation systems

Autonomous Underwater Vehicles (AUV) are rapidly being transitioned into operational systems for national defense, offshore exploration, and ocean science. However, the use the robotic platforms as components of integrated acoustic sensing systems is still at an early stage. Thus, for example, with recent advances in underwater navigation and communication, and collaborative robotics, networks of AUVs may have significant potential as moving tomographic networks for optimally and adaptively providing in-situ environmental estimates. Such concepts are important to the development and operation of environmenatally adaptive, autonomous littoral surveillance systems by providing environmental inversion specifically emphasizing the parameters significant for the actual platform configuration. Also such multi-AUV concepts have significant potential for subbottom characterization in the deep ocean, of increased importance in the offshore industry. For such systems to be operationally feasible, the limited underwater communication bandwidth makes it necessary for such systems to involve significant on-board processing, in turn requiring the acoustic sensing to be fully integrated with an onboard modeling capability and the platform navigation and control. The development of such new nested, distributed processing concepts, autonomously integrating sensing, modeling and control, is a significant challenge to the acoustics community. [Work supported by ONR.]

Underwater Vehicle Networks for Acoustic and Oceanographic Measurements in the Littoral Ocean

Recent progress in underwater robotics and acoustic communication has led to the development of a new paradigm in ocean science and technology, the Autonomous Ocean Sampling Network (AOSN). AOSN consists of a network of fixed moorings and/or autonomous underwater vehicles (AUV), tied together by state-of-the-art acoustic communication technology. The GOATS2000 (Generic Oceanographic Array Technology Systems) Joint Research Program is aimed toward the development of environmentally adaptive AOSN technology specifically directed toward Rapid Environmental Assessment in coastal environments. The research program combines theory and modeling of the 3-D environmental acoustics with experiments involving AOSN and sensor technology. To explore the potential of providing a reliable environmental forecasts of the coastal ocean, the observational capabilities are coupled with a nested ocean modeling and assimilation framework, consistently coupling basin scale oceanography with small scale ocean processes. The central element of the the program is a prototype underwater vehicle network managed remotely by a surface platform, including moored sources and arrays, AUVs equipped with a variety of acoustic and environmental sensors, and reliable navigation and communication system.