Abstract: Deploying a multi-hop underwater acoustic sensor network (UASN) in a large area brings about new challenges in reliable data transmissions and survivability of network due to the limited underwater communication range/bandwidth and the limited energy of underwater sensor nodes. In order to address those challenges and achieve the objectives of maximization of data delivery ratio and minimization of energy consumption of underwater sensor nodes, this paper proposes a new underwater routing scheme, namely AURP (AUV-aided underwater routing protocol), which uses not only heterogeneous acoustic communication channels but also controlled mobility of multiple autonomous underwater vehicles (AUVs). In AURP, the total data transmissions are minimized by using AUVs as relay nodes, which collect sensed data from gateway nodes and then forward to the sink. Moreover, controlled mobility of AUVs makes it possible to apply a short-range high data rate underwater channel for transmissions of a large amount of data. To the best to our knowledge, this work is the first attempt to employ multiple AUVs as relay nodes in a multi-hop UASN to improve the network performance in terms of data delivery ratio and energy consumption. Simulations, which are incorporated with a realistic underwater acoustic communication channel model, are carried out to evaluate the performance of the proposed scheme, and the results indicate that a high delivery ratio and low energy
consumption can be achieved.
Long range underwater acoustic communication achievement is a decisive milestone for very long cruising AUVs deployment (>1000 km). This paper describes a new kind of acoustic source designed and manufactured by iXSea, the Janus-Hammer Bell (JHB), which was recently used in the at-sea experiments for longrange communication by JAMSTEC. The modem center frequency was 500 Hz, and its bandwidth 100Hz. It provided a 200dB (ref.1μPa@1m) flat signal level spectrum with full immersion capability and was designed to be battery operated. This patented underwater acoustic source was exploited in a “passive timereversal” process. This method newly achieved long range communication at a rate of 100bit/s at 1000km.More
The Micro-Modem is a compact, low-power, underwater acoustic communications and navigation subsystem.
It has the capability to perform low-rate frequency-hopping frequency-shift keying (FH-FSK), variable rate phase-coherent keying (PSK), and two different types of long base line navigation, narrow-band and broadband. The system can be configured to transmit in four different bands from 3 to 30 kHz, with a larger board required for the lowest frequency. The user interface is based on the NMEA standard, which is a serial port specification. The modem also includes a simple built-in networking capability which supports up to 16 units in a polled or random-access mode and has an acknowledgement capability which supports guaranteed delivery transactions. The paper contains a detailed system description and results from several tests are also presented.
This paper provides an overview of the Naval Postgraduate School ARIES autonomous underwater vehicle. An attempt is made to highlight its’ current operational capabilities and provide a description of future enhancements for greater mission utility and flexibility. An overview of the vehicle design along with descriptions of all major hardware components and sensors is given. A major discussion of the implementation of a modular, multi-rate, multi-process
software architecture for the ARIES is provided. The architecture is designed to operate using a single computer
processor or two independent, cooperating processors linked through a network interface for improved load balancing. A dual computer implementation is presented here since each processor assumes different tasks for mission operation. Also included is a section on the underwater navigation method used. It involves the use of a real-time extended Kalman filter that fuses all sensor data and computes the real time position, orientation, velocity, etc., of the vehicle. Issues of navigational accuracy of the filter are also discussed. The work concludes with a discussion of using the ARIES as a communications server in a multi-vehicle environment. It is proposed to use the ARIES as a mobile communications relay between a command and control station on the surface and multiple vehicles operating below. The advantages of using a mobile relay over fixed buoys are discussed.
This Paper considers the problem of cooperative mapping and navigation (CMAN) by multiple unmanned underwater vehicles (UUVs). The goal is for several UUVs to concurrently build maps of an unknown environment, and to use these maps for navigation. This work builds on our previous research in development of concurrent mapping and localization (CML) techniques for a single vehicle. In this paper, cooperative stochastic mapping is proposed as a new framework for featurebased CML by multiple vehicles. Previous research related to cooperative mapping and navigation is reviewed. New research issues encountered, such as information transfer management, decentralized data fusion, and cooperative adaptive sampling are discussed.More