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REMUS real-time telemetry plot showing planned tracks of two vehicles performing a two-phase mine countermeasure mission. Blue crosses (+) show position reports from an SCM vehicle which has been re-directed for a closer look over a target, while the yellow crosses (+) are from a RI vehicle with dual frequency sonar and a low-light video camera. Both missions are operator-initiated in this case.
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Autonomous Underwater Vehicles (AUVs) are an alternative to traditional mine countermeasures (MCM) operations using divers or marine mammals. REMUS AUVs can be deployed at a distance and map an area using side-scan sonar, then identify and classify bottom targets using on-board processing. A shallow water acoustic communications network has been im...
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... system was recently deployed in May 2004 in Camp LeJeune, as part of a Combined Joint Task Force Exercise. It was operated for several weeks, and successfully detected mine and mine-like objects using multiple vehicles operating simultaneously. Several prototypical MCM missions that were performed are described below. The first phase of work is the Search-Classify-Map with side-scan sonar. The AUV reports CAD/CAC scores to the operator in real time through the gateway buoy, as shown in Figure 7. The operator watches the scores as the mission progresses and is able to get a feel for how many mine-like objects are present in the survey area while it is still on-going. In Fig. 7 the purple lines represent the vehicle’s planned track, and the yellow and white crosses show the position where real-time data was sampled, transmitted acoustically, received by the gateway buoy, then displayed for the user on shore. The network allows multiple vehicles to be monitored and remotely controlled. Fig. 8 shows the tracks from two vehicles operating in the same area. The first vehicle has performed a SCM mission and reports CAD/CAC targets back to the operator. The operator sends the vehicle back for a second look at two different aspects from the target to get multiple views. A RI vehicle, which has been on standby waiting for tasking, is vectored into the same area to perform a close-in mission with dual-frequency side-scan and a low-light video camera. All vehicles in the network monitor communications traffic. Thus when a SCM vehicle reports CAD/CAC messages to a central station, they are also received by a nearby RI vehicle. The RI vehicles can also be programmed to act on CAD/CAC messages automatically. The score and the location are used to prioritize the targets and maintain a list of redirect missions to be carried out. This capability forms the basis for a completely autonomous group of vehicles performing both SCM and RI missions without a human in the loop. Vehicles that are equipped with side-scan sonar and a re-acquisition sensor such as a high-frequency side-scan, video camera, or forward-look sonar can also carry out redirect missions by themselves when a CAD/CAC target score exceeds a pre-set threshold. This has been used successfully to perform SCM plus RI missions together on one AUV. Only vehicles which have a modem are allowed to use this mode because the modem is necessary to keep track of the mission. If no modem were available it would be impossible to know what was happening. The performance of the system during actual tests has been very good. The range of the system depends heavily upon the local acoustic conditions, but is typically 2000 m or greater. In environments that are well-mixed with a hard bottom the range can be 3000 m or more, while in heavily stratified conditions with surface warming (which causes downward refraction) and an absorbing bottom, the range can be substantially less, occasionally 1000 ...
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Citations
... Over the decades, a multitude of geomorphometric techniques have utilized bathymetric sensors to characterize seafloor stretching attributes (Chakraborty et al., 2013;Masetti et al., 2018;Neil et al., 2019;Pillay et al., 2020;Wang et al., 2021a;Wang et al., 2021b). The increasing use of underwater vehicles, such as Autonomous Underwater Vehicles (AUVs) or Remotely Operated Vehicles (ROVs), e.g., Bluefin (Panish and Taylor, 2011), Hugin (Marthiniussen et al., 2004), Remus (Freitag et al., 2005), Autosub (Furlong et al., 2012), JAMSTEC (Tamura et al., 2000), Urashima (Sawa et al., 2005), and so forth, provides more opportunities to facilitate deep-sea inspection with flexibility and adaptability (Singh et al., 2004;Bewley et al., 2012;Smale et al., 2012;Huvenne et al., 2018). ...
The increasing use of underwater vehicles facilitates deep-sea exploration at a wide range of depths and spatial scales. In this paper, we make an initial attempt to develop online computing strategies to identify seafloor categories and predict biogeographic patterns with a deep learning-based architecture, DenseNet, integrated with joint morphological cues, with the expectation of potentially developing its embedded smart capacities. We utilized high-resolution multibeam bathymetric measurements derived from MBES and denoted a collection of joint morphological cues to help with semantic mapping and localization. We systematically strengthened dominant feature propagation and promoted feature reuse via DenseNet by applying the channel attention module and spatial pyramid pooling. From our experiment results, the seafloor classification accuracy reached up to 89.87%, 82.01%, and 73.52% on average in terms of PA, MPA, and MIoU metrics, achieving comparable performances with the state-of-the-art deep learning frameworks. We made a preliminary study on potential biogeographic distribution statistics, which allowed us to delicately distinguish the functionality of probable submarine benthic habitats. This study demonstrates the premise of using underwater vehicles through unbiased means or pre-programmed path planning to quantify and estimate seafloor categories and the exhibited fine-scale biogeographic patterns.
... Applications in different human activities in the underwater environment have become very important and opened a new field for investigators interested in this area. Many researchers such as [3][4][5][6][7][8][9][10][11][12] have proposed solutions to fulfill human requirements and needs in such a harsh environment for industry (detecting chemical pollution, pipeline monitoring, biological phenomena, and seismic studies), government (military applications and maintaining the coast), and nature (hazard events, marine farms, ecological monitoring, and contamination studies). The underwater sensor design in such applications ranges from simple to complex [13]. ...
One of the most challenging issues in the routing protocols for underwater wireless sensor networks (UWSNs) is the occurrence of void areas (communication void). That is, when void areas are present, the data packets could be trapped in a sensor node and cannot be sent further to reach the sink(s) due to the features of the UWSNs environment and/or the configuration of the network itself. Opportunistic routing (OR) is an innovative prototype in routing for UWSNs. In routing protocols employing the OR technique, the most suitable sensor node according to the criteria adopted by the protocol rules will be elected as a next-hop forwarder node to forward the data packets first. This routing method takes advantage of the broadcast nature of wireless sensor networks. OR has made a noticeable improvement in the sensor networks’ performance in terms of efficiency, throughput, and reliability. Several routing protocols that utilize OR in UWSNs have been proposed to extend the lifetime of the network and maintain its connectivity by addressing void areas. In addition, a number of survey papers were presented in routing protocols with different points of approach. Our paper focuses on reviewing void avoiding OR protocols. In this paper, we briefly present the basic concept of OR and its building blocks. We also indicate the concept of the void area and list the reasons that could lead to its occurrence, as well as reviewing the state-of-the-art OR protocols proposed for this challenging area and presenting their strengths and weaknesses.
... The military uses UWSN to keep track of activities both over and underwater at the sea border. They use imaging, sonar, and other sensors for surveillance, mine detection, and locating submarines [82,83]. ...
Underwater wireless sensor networks (UWSNs) are a prominent research topic in academia and industry, with many applications such as ocean, seismic, environmental, and seabed explorations. The main challenges in deploying UWSN are high ocean interference and noise, which results in longer propagation time, low bandwidth, and changes in network topology. To mitigate these problems, routing protocols have been identified as an efficient solution. Over the years, several protocols have been proposed in this direction and among them, the most popular are the ones that use multi-path propagation. However, there is a lack of compilation of studies that highlight the advancement of multi-path routing protocols of UWSN through the years. Hence, getting a heuristic idea of the existing protocols is crucial. In this study, we present a comprehensive survey of UWSNs multi-path routing protocols and categorize them into three main categories; energy-based routing protocols, geographic information-based routing protocols, and data-based routing protocols. Furthermore, we sub-classify them into several categories and identify their advantages and disadvantages. In addition, we identify the application of UWSN, open challenges and compare the protocols. The findings of our study will allow researchers to better understand different categories of UWSN multi-path routing protocols in terms of their scope, advantages, and limitations.
... The network designed here works as a master-slave network, where almost every data gathered by the vehicles get transmitted to the surface buoy with a high-rate receiver. A method to improve the reliability of the PSK by using multiple receiver channels is mentioned in Freitag et al. (2005). Multi-Channel input is introduced by incorporating another small card along with a DSP card and co-processor cards. ...
Underwater Mobile Sensor Network (UWMSN) has marked a new era in ocean observation systems involving large scale ocean phenomena monitoring applications. These spatial and temporally varying applications demand multiple mobile entities for the collection of large amounts of data. This paper gives a concise view of the current state of the art of such networks comprising multiple Autonomous Underwater Vehicles (AUVs) and their challenges. It provides a literature review of the channel model and networking protocols of the physical layer, data link layer and network layer. Important algorithms and techniques for localisation and time synchronisation have also been reviewed. These algorithms play a huge role in a cooperative mission involving multiple AUVs, to achieve a common notion of time and to share the location information among the vehicles. Moreover, this paper includes a survey of various software platforms that support UWMSN, testbeds/real-time deployments of UWMSN developed by various research institutes/organizations and briefly discusses the recent advancement in the field of UWMSN.
... Another aspect is mechanical engineering methods of diagnostics for ship equipment [9,13], using on-board and external measurement systems. A further area of underwater noise research is the safety of the ship in terms of the threat from non-contact mines with hydroacoustic igniters [5,6]. In addition, studies have been conducted for statistical purposes for different types of customers, for example physicists, biologists, logisticians and various services connected with maritime transport. ...
A ship moving over the surface of water generates disturbances that are perceived as noise, both in the air and under water. Due to its density, water is an excellent medium for transmitting acoustic waves over long distances.
This article describes the impact of the settings of a ship’s machinery on the nature of the generated noise. Our analysis includes the frequency characteristics of the noise generated by the moving ship. Data were obtained using an underwater measurement system, and the measured objects were two ships moving on specific trajectories with certain machinery settings. The acquired data were analysed in the frequency domain to explore the possibilities of the acoustic classification of ships and diagnostics of source mechanisms.
... Moreover, the video monitoring systems used for collecting data for coastal environment management (Davidson et al., 2006) will improve with a higher understanding of nearshore currents. Second, currents affect autonomous underwater vehicles that in recent years have been used for research/data collection (Greiner et al., 1996;Moline et al., 2005) and coastal defense (Chen et al., 2013;Freitag et al., 2005). The vehicles are propelled underwater by crawling, with wheels, or by swinging motions. ...
Suzuki, T. and Cox, D.T., 2019. Statistical analysis of longshore currents on a barred beach. Journal of Coastal Research, 35(6), 1215–1224. Coconut Creek (Florida), ISSN 0749-0208.
Longshore currents were observed using a horizontally mounted acoustic Doppler current profiler in the nearshore on a dissipative barred beach. The data were taken for 20 days from 13 May to 2 June 2016. Wave, current, water level, and wind data were continuously observed. From a statistical point of view, the exceedance probability/occurrence ratio of higher currents is important. Therefore, in this research, the hourly data were used to investigate the spatial and wave-energetic distributions of exceedance probability of the longshore currents. Moreover, the effect of tidal range on this exceedance probability is discussed. From the analysis, the exceedance probabilities of longshore currents were well predicted by the Weibull distribution, with parameters estimated using the normalized wave energy flux, relative surf-zone location, and normalized water depth. The exceedance probability of the longshore current was largely affected by water level (tidal elevation): during high tide it was the same or lower than that of the full data set. However, the exceedance probability was approximately two times larger during low tide than that using the full data set.
... The vehicle is visible in Fig. 1, during one of the preliminary tests. Nowadays AUVs can be involved in many fields of interest, in order to reduce the costs of experimental campaigns or human intervention in areas at risk, among them: oceanography [2], marine geoscience [3], defence [4], underwater installations inspection [5] and underwater archaeology, the field of application of the following projects; THESAURUS [6], ARROWS [7] and ARCHEOSUb (logo visible in Fig. 2). Unlike already known commercial AUVs, typically with a torpedo-shape, (gliders e.g. ...
... The role of the vehicle within an archaeological campaign is not too much different from a mission against mines [4] concerning the phases of search and inspection: in the first one, acoustic payloads, such as SSS and FLS, can be employed for quickly and ample surveying, to identify and mapping interesting places and targets, technically called "candidate points" [18]. Obviously, the speed of the vehicle and the range of SSS decrease the mission time and increase the rate of exploration: for a good quality data acquisition, the operational speed is usually around 1 kn. ...
... Recent advances in autonomous underwater vehicle (AUV) technology have facilitated growing roles for AUVs in mission-critical tasks such as underwater acoustic communications, remote intelligence retrieval, tactical surveillance, naval operations, military countermeasures, and oceanography (Chitre et al., 2008;Yuh, 2000). Most of the AUV studies in the literature cover vehicle guidance, navigation, path determination, or point-to-point communications (Freitag et al., 2005;Yoerger et al., 2007;Jia et al., 2012). However, reliable and adaptive networking protocols must be developed to overcome the drawbacks of underwater acoustic channel such as low data rate, limited bandwidth, and large propagation delay. ...
Autonomous underwater vehicle (AUV) networks are used for coordinated missions such as area mapping and
remote surveillance. AUVs are typically deployed by a central platform such as a ship or a submarine, and they
operate in an unattended environment. Although there is no need for continuous monitoring of AUV nodes, the
central platform may occasionally need to send messages, route updates, or mission commands to the AUV fleet.
Nodes in an AUV network are mobile and self-powered. Moreover, periodic exchange of neighborhood messages
is not practical due to large propagation delays. Therefore, reliable, low-latency, and energy-efficient solutions
are needed to meet the performance requirements of ad hoc AUV networks. We propose P-AUV as a routing and
medium access protocol, which depends on location estimation at each node. Data required for packet relaying
decision is carried in the header of each data packet. Loop-free routes are generated, where relay candidates
closer to the sink nodes are prioritized. In order to control medium access and to avoid collisions, each node
selects a backoff interval according to its own position. We analyze the performance of our solution and we
compare P-AUV with probabilistic broadcast in terms of several network parameters. Our results indicate that
P-AUV improves packet delivery ratio and end-to-end delay along with lifetime of AUV networks.
... In order to avoid this interference, a simple solution is to schedule the transmissions by a Time-Division Multiple Access (TDMA) protocol, where only one reception can happen at any receiver at any time. The users are assigned different time slots to communicate with each other [21]- [25], or the arrival times are estimated in advance in order to overlap transmissions to increase channel use [26]. On the one hand, user identification and collision avoidance is straightforward. ...
The correct detection of arrivals is a crucial step in any communication system, in order to achieve frame synchronization. This step is even more relevant in underwater acoustic communications, as the medium is characterized by hazardous phenomena such as long multipath delays and non-uniform Doppler shifts, which hinder the detection process. All these phenomena make the detection of arrivals and identification of multiple users in underwater communication systems a challenging task. In this work, a multi-user detector is presented. The detection is based on the Direct-Sequence Code-Division Multiple Access technique (DS-CDMA), by using a combination of two sequences as a preamble: a Zadoff-Chu sequence that provides candidate peaks and frame synchronization, and a Complementary Set of Sequences (CSS) that validates the true Zadoff-Chu arrival while at the same time identifies the user. Both sequences are modulated using multi-carrier techniques, and the users can transmit asynchronously to the channel. In the case of CSS, multi-carrier modulation techniques allow to perform channel equalization and demodulation at the receiver in a simple manner, enabling the correlation of the CSS at bit level, thus keeping its ideal correlation properties. Sea trials were conducted in February of 2017 at Suruga Bay, Japan, in which the reception of two different users was analyzed under different noise and multipath conditions, as well as uniform and non-uniform Doppler shifts. The results show that, even under strong multipath and non-uniform Doppler shifts caused by roll and pitch motions, the receiver is able to detect and identify the user in 98% of the transmitted packets.
... Submarine Wireless Sensor Networks (SWSNs) used to observe the vast unfamiliar submarine field of the ground. SWSN facilitates broad range of applications such as environment observing, aided navigation, quarry detection, and calamity prevention [1], [2]. The acoustic signals contribute a lot of disputes owing to fixed bandwidth, bit error rate (BER) and high mobility. ...
Submarine Wireless Sensor Networks (SWSNs) have earned important concentration of both university and manufacturing in current years. In this paper, we introduce intensity and trustworthiness awake delay perspective (ITADP) routing protocol for submarine WSNs. We get inspiration from Submarine Opportunistic Routing (SOR) protocol that explains expected end-to-end latency from Sender sensor to sink. We consider two faults in SOR. Initially, in SOR protocol, sensor transmit the information to intermediate node that have higher trustworthiness missing the depth of the forwarder node, thus create more hop counts. The coordination time of intermediate sensor cluster is second fault that increases the latency. Thus, we introduce Intensity and trustworthiness awake routing in submarine WSNs. © 2018 Institute of Advanced Engineering and Science. All rights reserved.
