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USVs (unmanned surface vehicles) for carrying underwater sensors to survey the underwater environment of communication cables.
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![Distribution of underwater communication cables on Earth [2]. The cable...](publication/338907828/figure/fig1/AS:11431281391044140@1745306556686/Distribution-of-underwater-communication-cables-on-Earth-2-The-cable-routes-are_Q320.jpg)
Underwater communication cables transport large amounts of sensitive information between countries. This fact converts these cables into a critical infrastructure that must be protected. Monitoring the underwater cable environment is rare and any intervention is usually driven by cable faults. In the last few years, several reports raised issues ab...
Contexts in source publication
Context 1
... are vehicles that operate (autonomously or remotely operated, ROVs) on the sea-surface without a crew. Table 2 presents the most relevant specifications of some commercial USVs that could be used to carry the identified sensors to survey the underwater environment of the cables. -Autonomous Underwater Vehicles (AUVs) ...Context 2
... cameras can be video or stills. Table 20 presents the main specifications of some identified commercial video cameras. The cameras can have high-definition properties, making them appropriate for short-range surveillance tasks and scientific observations. ...Context 3
... significant change in the pH value of the seawater in the underwater environment where a cable is may lead to the detection of the presence of the underwater object generating such a pH change. Table 22 presents the main specifications of identified commercial systems that measure the oceanographic variables studied above, which are relevant to survey the underwater environment where communication cables are. ...Context 4
... detection inside the warning zone should require immediate action. A schematic representation of these monitoring areas/zones is presented in Figure 7. Table 23 summarizes the main parameters for the multi-threat sabotage scenario under study. ...Context 5
... threats, which are considered in this case study (see Table 23) are listed below, for which recommended sensors are provided in the following subsections: ...Context 6
... the cable can be reached only through excavation for the first 1000 m of water depth, the threat activity could be indirectly traced by ADCPs (see Table 17) and/or turbidity sensors (see Table 22). ADCPs' advantage is that they have usually a vertical beam and 4 slanted beams at 20 o or 25 o and a range that starts from 30 m and can reach up to 1000 m. ...Context 7
... USVs or UUGs having oceanographic sensors (see Table 22) could be used for detecting potential anomalies in the underwater environment due to the presence of ROVs or AUVs. ...Context 8
... and fishing trawls heavily disturb the seabed sediment. Therefore, ADCPs (see Table 17) and turbidity sensors (see Table 22) can be used to detect them. As mentioned in the previous sub-section (4.2.1), ADCPs usually have 5 beams (4 slanted at 20 o , and one vertical) and can detect changes in the water current velocities due to suspended particles in a conical shape-area around the water column. ...Context 9
... issue with these sensors (except DS) is their size, requiring large platforms/vessels for their operation. It can be seen in Table 2 that there are USVs now available that can accommodate light towed arrays and dipping sonars. Therefore, it is possible to use these two systems on USVs to monitor the underwater area of the cables against submarine threats. ...Context 10
... (Table 2) have ranges from 22 to 5329 km. In many cases their range is greater than 1000 km, being sufficient to cover the EEZ. ...Context 11
... and cable cut detection requires comparison of the seabed, where the cable is buried, at different times in order to identify any changes on the seabed environment. As mentioned in Section 4.1 and shown in Table 23, divers, ROVs and AUVs (with manipulating arms) could tape or cut underwater cables. ...Context 12
... swath covered by these systems depends on the water depth. So the limits X1 and X2 of the monitoring and surveillance zones (see Table 23), respectively, cannot be conveniently calculated here as the depth in the case study ranges from very shallow to 4000 m. Therefore, each water depth may require a different coverage regarding the selected systems and the number of them needed. ...Context 13
... are vehicles that operate (autonomously or remotely operated, ROVs) on the sea-surface without a crew. Table 2 presents the most relevant specifications of some commercial USVs that could be used to carry the identified sensors to survey the underwater environment of the cables. -Autonomous Underwater Vehicles (AUVs) ...Context 14
... global inventory of AUVs and UUGs available in the commercial market can be found in [23]. Tables 2-4 present the main specifications of the selected USVs, AUVs, and UUGs available on the market. The most favorable values provided by the manufacturers in the specification brochures have been selected to compose the tables. ...Context 15
... cameras can be video or stills. Table 20 presents the main specifications of some identified commercial video cameras. The cameras can have high-definition properties, making them appropriate for short-range surveillance tasks and scientific observations. ...Context 16
... significant change in the pH value of the seawater in the underwater environment where a cable is may lead to the detection of the presence of the underwater object generating such a pH change. Table 22 presents the main specifications of identified commercial systems that measure the oceanographic variables studied above, which are relevant to survey the underwater environment where communication cables are. ...Context 17
... detection inside the warning zone should require immediate action. A schematic representation of these monitoring areas/zones is presented in Figure 7. Table 23 summarizes the main parameters for the multi-threat sabotage scenario under study. ...Context 18
... threats, which are considered in this case study (see Table 23) are listed below, for which recommended sensors are provided in the following subsections: ...Context 19
... the cable can be reached only through excavation for the first 1000 m of water depth, the threat activity could be indirectly traced by ADCPs (see Table 17) and/or turbidity sensors (see Table 22). ADCPs' advantage is that they have usually a vertical beam and 4 slanted beams at 20 o or 25 o and a range that starts from 30 m and can reach up to 1000 m. ...Context 20
... USVs or UUGs having oceanographic sensors (see Table 22) could be used for detecting potential anomalies in the underwater environment due to the presence of ROVs or AUVs. ...Context 21
... and fishing trawls heavily disturb the seabed sediment. Therefore, ADCPs (see Table 17) and turbidity sensors (see Table 22) can be used to detect them. As mentioned in the previous sub-section (4.2.1), ADCPs usually have 5 beams (4 slanted at 20 o , and one vertical) and can detect changes in the water current velocities due to suspended particles in a conical shape-area around the water column. ...Context 22
... issue with these sensors (except DS) is their size, requiring large platforms/vessels for their operation. It can be seen in Table 2 that there are USVs now available that can accommodate light towed arrays and dipping sonars. Therefore, it is possible to use these two systems on USVs to monitor the underwater area of the cables against submarine threats. ...Context 23
... (Table 2) have ranges from 22 to 5329 km. In many cases their range is greater than 1000 km, being sufficient to cover the EEZ. ...Context 24
... and cable cut detection requires comparison of the seabed, where the cable is buried, at different times in order to identify any changes on the seabed environment. As mentioned in Section 4.1 and shown in Table 23, divers, ROVs and AUVs (with manipulating arms) could tape or cut underwater cables. ...Context 25
... swath covered by these systems depends on the water depth. So the limits X1 and X2 of the monitoring and surveillance zones (see Table 23), respectively, cannot be conveniently calculated here as the depth in the case study ranges from very shallow to 4000 m. Therefore, each water depth may require a different coverage regarding the selected systems and the number of them needed. ...Citations
... With the expansion of underwater fiber optic networks, the potential for further innovations in technology and applications continues to grow. Future applications may include more advanced transmission technologies that offer even higher speeds and security [70], as well as the potential to integrate with new forms of underwater robotic systems that could improve ocean research and surveillance [71]. ...
This review examines current underwater communication technologies, highlighting the challenges and innovations in applications spanning scientific research, exploration, environmental monitoring, and security. Emphasis is placed on the evolution and interplay of acoustic, optical, quantum, and hybrid communication methods, as well as their respective limitations and potential solutions in the complex underwater environment. The review explores advancements in Autonomous Underwater Vehicles (AUVs), with particular focus on the swarm configuration, which enables dynamic, interconnected networks for real-time data exchange and adaptive responses to environmental changes. Key areas of innovation include the use of new materials, advanced sensor networks, and machine learning algorithms to enhance communication efficiency, security, and resilience under varying underwater conditions. The integration of swarm AUVs and Internet of Things (IoT) concepts is proposed to further expand underwater operational capabilities, making underwater communication systems more reliable, secure, and versatile.
... These subsea power and control systems are installed on the seabed, with umbilical cords connecting subsea equipment to surface facilities, providing fast, reliable, and robust underwater cabled communication [49]. Like airborne systems, underwater cables are widely used for various purposes, including communications, power transmission, and distribution to islands, oilfield platforms, and underwater infrastructure [78]. However, unlike airborne cables, underwater cables require more specific design considerations for protection and shape to withstand the marine environment, including factors such as pressure, temperature, ocean currents, salinity, and water ingress [55]. ...
Approximately 75% of the Earth’s surface is covered by water, and 78% of the global animal kingdom resides in marine environments. Furthermore, algae and microalgae in marine ecosystems contribute up to 75% of the planet’s oxygen supply, underscoring the critical need for conservation efforts. This review systematically evaluates the impact of underwater communication systems on aquatic ecosystems, focusing on both wired and wireless technologies. It highlights the applications of these systems in Internet of Underwater Things (IoUT), Underwater Wireless Sensor Networks (UWSNs), remote sensing, bathymetry, and tsunami warning systems, as well as their role in reducing the ecological footprint of human activities in aquatic environments. The main contributions of this work include: a benchmark of various underwater communication systems, comparing their advantages and limitations; an in-depth analysis of the adverse effects of anthropogenic emissions associated with communication systems on marine life; and a discussion of the potential for underwater communication technologies, such as remote sensing and passive monitoring, to aid in the preservation of biodiversity and the protection of fragile ecosystems.
... In recent years, towed systems have been increasingly used across various fields due to their significant benefits. As illustrated in Figure 1, these fields primarily include seafloor topographic exploration [9,10], marine environment monitoring [11,12], marine rescue, protection of marine organisms [13,14], marine resources exploration [15,16], underwater archeology [17,18], and military applications [19][20][21]. As illustrated in Figure 2, the overall trend in the amount of literature on towing cable arrays has been increasing year by year, indicating a growing emphasis on this area. ...
Towing cable arrays have made significant contributions across various fields, and their outspread process is crucial for realizing their functionalities. However, research on the dynamic characterization of the outspread process of towed cable arrays lacks systematic organization. This paper reviews, organizes, and analyzes the outspread process of towing cable arrays, drawing on relevant models, case studies, and structural features. It ingeniously applies concepts from parachute outspread to the analysis of towing-cable-array deployment. The study systematically examines the deployment of towing cable arrays under varying cable lengths, wave conditions, and the interactions between line arrays. The goal is to integrate existing research on the outspread of towing cable arrays, addressing the gaps in the description of this process and providing a comprehensive analysis of the outspread characteristics under different conditions. Additionally, this paper identifies current limitations in this area and provides insights for future developments. Furthermore, it explores the potential application of AI to address these challenges. The aim of this paper is to contribute meaningfully to this field.
... At low frequencies ( f < 500 Hz), in particular, propagation in shallow waters can be effectively described by the normal mode theory, wherein waves propagate with different speeds in distinct modes [11,12]. Note though that these frequencies fall outside the scope of the thesis; for reference, the frequency range of interest in the thesis spans from approximately 1 kHz to 10 kHz, which covers the frequencies typically used by the passive-sonar arrays mounted onto modern submarines [2,13,14]. It is important to note that although underwater sources may have spectral content at higher frequencies and hydrophones can sample up to 500 kHz, the hull-mounted hydrophone arrays (see Section 2.1.2) are usually optimised to work within the aforementioned range. ...
This thesis consists of five publications that focus on the development and evaluation of techniques designed for passive sonar applications utilising hydrophone arrays. The research specifically explores the topic of underwater soundfield visualisation on the horizontal plane for bearing estimation and tracking of sound-emitting targets. The explored techniques draw their inspiration from established microphone array techniques, widely adopted in the field of spatial audio, presenting novel approaches to traditional localisation problems in the underwater domain.
In particular, the first publication proposes a novel spatial post-filter in the circular harmonic domain suitable for application in large circular hydrophone arrays, similar to those found in modern submarines. This proposed post-filter is essentially an extension of the Cross-Pattern Coherence (CroPaC) post-filter to higher orders of circular harmonics. The second and third publications concern the development of a space-domain version of CroPaC, i.e., a version that operates directly on the hydrophone array signals, eliminating the need for conversion into the circular harmonic domain. This aspect holds particular significance for passive sonar, as it enables the application of CroPaC to linear arrays, which are the predominant type of arrays used in underwater acoustics. The fourth publication proposes a novel approach for underwater soundfield visualisation using circular hydrophone arrays. The proposed approach is inspired by the soundfield analysis performed in Higher-Order Directional Audio Coding (HO-DirAC), a parametric spatial audio technique which extracts spatial parameters from directionally constrained regions termed sectors. Finally, the fifth publication proposes the use of an optimal mass transport framework for bearing estimation and tracking of underwater targets, achieved by solving a convex optimisation problem.
The evaluation of the techniques was conducted using hydrophone array data obtained from highly detailed numerical simulations as well as real-world hydrophone array recordings. The examined array types include linear arrays with both baffled and open designs, as well as circular arrays mounted on cylindrical baffles. In the majority of cases, the array designs were chosen to align with specifications of arrays commonly used in passive sonar operations with submarines. The performance of the proposed techniques demonstrated significant improvements over conventional passive sonar techniques in many cases. These improvements pertain to the accuracy
of bearing estimation, the side-lobe suppression capability, the separation of closely spaced targets, the computational complexity, and the robustness to noise, interference, and model mismatch. Lastly, it is noted that, while the evaluation primarily focused on specific hydrophone arrays of special interest deployed in shallow-water environments, the results have broader applicability and may therefore be generalised to other use cases.
... Submarine cables have a complex structure and operate in harsh environments, making them susceptible to various external loads that can lead to failures. According to recent statistics on cable faults, nearly 70% of damage to submarine cables results from anchor impacts and fishing activities [3,4]. The hooking and dragging of anchors and fishing nets by ships pose the primary threats to the safe operation of submarine cables. ...
Anchor damage is one of the main risk factors for the safe operation of submarine cables. Additionally, due to a scour effect induced by seabed currents, submarine cables are prone to exposure or even suspension, increasing the risk of being dragged by anchors. Therefore, it is necessary to study the global response of exposed and suspended submarine cables subjected to anchor dragging. In this study, the tensile and bending stiffnesses of submarine cables are calculated by theoretical methods, and the accuracy of these calculations is verified by establishing a detailed finite element model. Then, the mechanical properties of the submarine cables are equivalently modeled using beam elements, and a large-scale finite element model for exposed and suspended cables under anchor dragging is established. Considering different dragging forces, exposed lengths, spanning lengths, and spanning heights, the overall deformation and mechanical responses of exposed and suspended cables are analyzed separately. The results show that under dragging forces, axial forces are uniformly distributed along exposed and suspended segments, while bending moments concentrate at the central hooking area and the ends of exposed and suspended segments. The influence of dragging force, exposed length, spanning length, and spanning height on the stress and deformation of submarine cables is significant. The results can be used for submarine cable damage assessments caused by anchor dragging.
... [3,4] For that reason, underwater sensing technologies have attracted huge interest from not only the scientific community but also various private and public-sector organizations. These technologies also have several defence and security applications, such as maritime surveillance, [5,6] mine detection, [7] communication cable protection, [8] or anti-submarine warfare. [9] Ocean exploration is traced back to the 19 th century when the HMS Challenger made the first oceanographic expedition, [10] but from that time until now, the technology and exploration methods have drastically advanced. ...
... One proposal in this domain is to use sensors to detect submarines or other potential dangers. These sensors could either be part of the cable itself (Eleftherakis & Vicen-Bueno, 2020) or a separate network (Wong, 2016). However, Bueger et al. suggest that by equipping submarine cables with the technology to detect submarines, cables would undermine their dual-use nature and make them valid military targets, putting civilian use at risk (Bueger et al., 2022). ...
The international network of submarine cables plays a crucial role in facilitating global telecommunications connectivity, carrying over 99% of all internet traffic. However, submarine cables challenge digital sovereignty due to their ownership structure, cross-jurisdictional nature, and vulnerabilities to malicious actors. In this article, we assess these challenges, current policy initiatives designed to mitigate them, and the limitations of these initiatives. The nature of submarine cables curtails a state’s ability to regulate the infrastructure on which it relies, reduces its data security, and threatens its ability to provide telecommunication services. States currently address these challenges through regulatory controls over submarine cables and associated companies, investing in the development of additional cable infrastructure, and implementing physical protection measures for the cables themselves. Despite these efforts, the effectiveness of current mechanisms is hindered by significant obstacles arising from technical limitations and a lack of international coordination on regulation. We conclude by noting how these obstacles lead to gaps in states’ policies and point towards how they could be improved to create a proactive approach to submarine cable governance that defends states’ digital sovereignty.
... These sensors are also suitable for monitoring the underwater environment where CUIs are located. In the operational research and analysis paper reported in [56] the examination of several commercial sensors is given. Among the already described, the MBES is a good candidate to perform fast mapping of the area with the additional capability to detect small targets. ...
The underwater environment poses numerous challenges and risks, making Unmanned Underwater Vehicles (UUVs) an indispensable alternative to human operators. Numerous Remotely Operated Vehicles (ROVs) and Autonomous Underwater Vehicles (AUVs) have been developed as a valuable resource in a broad spectrum of underwater operations. However, the deployment and operation of UUVs face significant challenges due to the unique underwater environment that critically affects Positioning, Navigation, and Timing (PNT) performance, making it incomparable to above-water applications. This discrepancy significantly impacts the decision-making process of industrial operators, particularly those in the sector of Critical Undersea Infrastructures (CUIs). Despite advancements, they persist in the use of heavy ROVs deployed from an expensive and environmentally impactful mothership for Inspection and Monitoring (I&M) tasks. To explore the potential revolutionary impact on underwater operations, we analyze the resilience of CUIs, and we review the most promising robotics developments that are currently or soon to be available. The forthcoming solutions not only promise to enhance the efficiency of I&M operations, thereby bolstering the security of CUIs, but they also have the potential to transform the broader field of underwater operations as a whole.
... Unauthorized or malicious use of these interfaces can lead to data leakage during transmission. Additionally, network management systems typically depend on HTTP or TCP/IP protocols for connections, which makes it easy for attackers to intercept protocol packets and analyze or obtain data information [12]. Attackers may also gain control over sensor nodes to steal or tamper with sensitive data [13]. ...
A seafloor observation network (SON) consists of a large number of heterogeneous devices that monitor the deep sea and communicate with onshore data centers. Due to the long-distance information transmission and the risk of malicious attacks, ensuring the integrity of data in transit is essential. A cryptographically secure frame check sequence (FCS) has shown great advantages in protecting data integrity. However, the commonly used FCS has a collision possibility, which poses a security risk; furthermore, reducing the encryption calculation cost is a challenge. In this paper, we propose a secure, lightweight encryption scheme for transmitted data inspired by mimic defense from dynamic heterogeneous redundancy theory. Specifically, we use dynamic keys to encrypt a data block and generate multiple encrypted heterogeneous blocks for transmission. These continuously changing encrypted data blocks increase the confusion regarding the original encoded data, making it challenging for attackers to interpret and modify the data blocks. Additionally, the redundant information from the multiple blocks can identify and recover tampered data. Our proposed scheme is suitable for resource-constrained environments where lightweight encryption is crucial. Through experimental demonstrations and analysis methods, we determine the effectiveness of our encryption scheme in reducing computational costs and improving security performance to protect data integrity.
... One of the many ways to obtain information about the seabed, depths and features lying on the seafloor is to conduct hydrographic surveys [6,7]. Hydrographic survey is a crucial activity in many underwater applications, such as ocean surveys, offshore oil and gas exploration, pipeline and underwater cables survey or mine clearance [8,9]. ...
Side-scan sonar is designed and used for a variety of survey work, in both military and civilian fields. These systems provide acoustic imageries that play a significant role in a variety of marine and inland applications. For this reason, it is extremely important that the recorded sonar image is characterized by high resolution, detail and sharpness. This article is mainly aimed at the demonstration of the impact of side-scan sonar resolution on the imaging quality. The article also presents the importance of acoustic shadow in the process of analyzing sonar data and identifying underwater objects. The real measurements were carried out using two independent survey systems: hull-mounted sonar and towed side-scan sonar. Six different shipwrecks lying in the Baltic Sea were selected as the objects of research. The results presented in the article also constitute evidence of how the sonar technology has changed over time. The survey findings show that by maintaining the appropriate operational conditions and meeting several requirements, it is possible to obtain photographic-quality sonar images, which may be crucial in the process of data interpretation and shipwreck identification.
