Naval Mine Research Articles

The Weapon That Cannot Be Silenced:

Among the most frequently utilized weapons in the First World War were naval mines, which have the ability to harm the enemy the most while costing the least. The major grounds for their preference were that they did not require any human involvement other than to prepare the required equipment and release it into the ocean and that they were made to last in the sea for a very long period of time without degrading. Unfortunately, because they could not be recovered immediately after a battle, these weapons, which offered enormous advantages against the enemy during the conflict, often remained to pose a menace after it had finished. As a case study, this essay intends to investigate the post-war situation of the hundreds of mines placed in the BlackSea during the First World War, mine detection and clearance activities, and the issues they raised. The article’s thesis is that conflicts can have long-lasting impacts.

A quantitative comparison of two different models of minefield transit

Naval mines are used to cause damage and inflict casualties on ships and to deny access to mined areas. Two distinctly different Monte Carlo models of surface ships transiting minefields were implemented and compared. An analytic model represents mines abstractly as mine density within the minefield. It determines the probability of a ship encountering a mine as a ratio of the area of the ship’s track through the minefield, with width equal to the mines’ effective radius and the area of the minefield. A geometric model represents the ship’s track and the mines’ locations explicitly. It determines whether a ship encounters a mine using a calculation of the distance between a ship’s track and the mines’ locations. The two models’ results were quantitatively compared for multiple values of five experimental variables: minefield dimensions, mine density, mine placement method, ships per group, and ship transit procedure. Each model was executed for each combination of experimental variable values and their results were compared to determine whether the models produced comparable results. In addition, the effectiveness of two mine placement methods at disabling ships and two ship transit procedures at avoiding mines were also compared. All comparisons used statistical hypothesis tests.

The Role of Explosive Ordnance Disposal Divers in Eliminating the Danger Generated by Naval Mines

Abstract Explosive Ordnance Disposal (EOD) divers are that category of soldiers from the Naval Forces with tasks and missions, equipment and specific training, which ensure the removal of the danger generated by explosive devices. One of the basic missions of EOD divers is the fight against sea mines, which are the most frequently used explosive devices in naval confrontations. To win the war against mines, all specialized structures must be used, depending on the specifics of the mission, no matter if we are talking about specialized ships, aviation or EOD divers.

A Visual-Inertial Pressure Fusion-Based Underwater Simultaneous Localization and Mapping System.

Detecting objects, particularly naval mines, on the seafloor is a complex task. In naval mine countermeasures (MCM) operations, sidescan or synthetic aperture sonars have been used to search large areas. However, a single sensor cannot meet the requirements of high-precision autonomous navigation. Based on the ORB-SLAM3-VI framework, we propose ORB-SLAM3-VIP, which integrates a depth sensor, an IMU sensor and an optical sensor. This method integrates the measurements of depth sensors and an IMU sensor into the visual SLAM algorithm through tight coupling, and establishes a multi-sensor fusion SLAM model. Depth constraints are introduced into the process of initialization, scale fine-tuning, tracking and mapping to constrain the position of the sensor in the z-axis and improve the accuracy of pose estimation and map scale estimate. The test on seven sets of underwater multi-sensor sequence data in the AQUALOC dataset shows that, compared with ORB-SLAM3-VI, the ORB-SLAM3-VIP system proposed in this paper reduces the scale error in all sequences by up to 41.2%, and reduces the trajectory error by up to 41.2%. The square root has also been reduced by up to 41.6%.

Hardware accelerated ray-tracing in ocean acoustics

Due to the expense and complexity of real-world data collection, machine learning applications in ocean acoustics demand ever-faster and more realistic models for training. In this talk, I discuss some recent GPU technologies which support hardware accelerated ray tracing and how they can be exploited to boost the throughput of certain types of calculations. Firstly, I describe RTX-Prop, which is a large-scale range-dependent Gaussian beam model which benefits from hardware-acceleration of bounding volume hierarchy searches and geometry intersection calculations. Designed to ingest oceanographic forecasts from the Royal Australian Navy’s Bluelink system, RTX-Prop has been developed as an embedded model to support tactical decisions by autonomous underwater vehicles. In the second application, I discuss hardware acceleration in the context of high-frequency sonar simulation. By synthesising fine-scale environmental detail, we have previously shown that simulated imagery can be almost indestinguishable from real data. Simulated sidescan and SAS imagery from our S4 model has recently become the basis of a machine-learning pipeline for training detectors and classifiers for naval mine countermeasures. [Work supported by the Trusted Autonomous Systems Defence Coorperative Research Centre.]

Magnetic signature reproduction of ferromagnetic ships at arbitrary geographical position, direction and depth using a multi-dipole model

The reproduction of magnetic signatures is an important issue concerning the safety of ship traffic, as well as the identification and classification of vessels. Moreover, military applications of magnetic signatures and their reproduction refer to the activation or protection against activation of magnetic naval mines. Previous works on this subject focused on recording and replicating the signatures under the same conditions as those under which they were measured, e.g., on the same ship courses. In this article, much greater capabilities of the multi-dipole model are presented, including simultaneous identification of permanent and induced magnetism. Determining the dipole values using the data from cardinal directions gives the possibility of determining the magnetic field density at any trajectory (position), direction, or depth, with further reconstruction of the entire magnetic field on the basis of residual measurements. For the purpose of this article, a numerical test model of a corvette-type ship has been modelled in Opera simulation software for different geographical positions. The synthetic data from the simulator served as the data source for determining the parameters of the multi-dipole model and the reference data for the verification of the signatures reconstructed for other positions, directions, and depths than those used to determine the model parameters. To determine all permanent magnetization components, data sets were used for two different values of the external magnetic field vertical component. Finally, as a culmination of the demonstration of model universality, the entire magnetic field around the ship was reproduced for different control points on Earth, and for different courses and depths. Investigating the possibility of reconstructing the magnetic signature at a different geographic location than the place where the measurement was made for model synthesis is the main original issue considered in this paper.

Underwater acoustic performance of SiC foam ceramic materials

One of the major tasks of the underwater warfare is to detect underwater objects such as vehicles, vessels, weapons and equipment. The conduct of underwater warfare mostly depends upon the advancement of detection and identification sensors and materials. The wide variation in types and characteristics of materials may affect the underwater detection capabilities despite recently developed sonar systems. The materials with high porosity are known to provide lower acoustical signature than conventional metallic plates in common. The aim of this study is to examine the acoustical signature and the efficiency of open celled SiC foam ceramics as covering and/or casing material for naval mines. Sonar frequencies widely used in mine countermeasure operations for detection purposes, 80 kHz, 85 kHz, 90khZ, 95 kHz and 100 kHz were applied to the acoustic tests. The experimental results obtained from the study shows that the SiC foam ceramic plate leads a 19,2% reduction in reflection, 90,5% and 96% lower values are obtained in transmission and 78,4% and 68,6% lower values are obtained at 60° and 30° in scattering compared to the reference steel plate.Article HighlightsThis study investigates underwater acoustic performance of open celled SiC foam ceramics the range of 80–100 kHz in the acoustic test pool environment for the very first time.Highly tortuose and porous structure of open celled SiC foam ceramic leads a considerable decrease in scattering, reflection and transmission properties.The study reveals that SiC foams ceramics are potential candidates in reducing acoustical signature as covering and/or casing material for future naval mine applications.

A prototype autonomous robot for underwater crime scene investigation and emergency response

AbstractUnderwater crime scene investigation and emergency response are tasks typically carried out by divers constituting part of a specialist team. Operating in such dynamic environments, often with poor visibility and risk of concealed hazards, can be time consuming and dangerous. Autonomous uncrewed vessels with underwater acoustic imaging sensors have been used for similar purposes in other fields (e.g., hydrography, naval mine countermeasures [MCMS], etc.) but have not been adopted in this specific application domain. The Police Robot for Inspection and Mapping of underwater Evidence (PRIME) is an autonomous uncrewed surface vessel that is being developed for this purpose. It is a novel application of existing robotic technology that is intended to be used within an end‐to‐end police and emergency underwater search process. It aims to enhance the effectiveness, efficiency, and safety of divers by autonomously locating and highlighting target objects or regions of interest, as well as benign regions, thereby reducing their time spent underwater. Side‐scan imaging sonars are used to sense the underwater environment using techniques leveraged from the similar application domain of naval MCMs. The system autonomously generates actionable intelligence in the form of simplified coverage and anomaly maps for easy interpretation by the dive team. These are communicated to shore in real‐time and georeferenced on satellite maps. This paper details the PRIME system prototype and presents results from initial field experimentation. The prototype has been operated in various urban, shallow‐water environments. The experimental results shown here were collected in Bristol Harbour (the UK) with a water depth of approximately 5 m. In the experiment, a clothed mannequin resembling a human body was deployed on the muddy floor. Autonomous searches were executed and the body was detected successfully as an anomaly against the background, illustrating the feasibility and viability of the system as an autonomous robotic aid for locating missing persons in a representative, unstructured, and dynamic real‐world environment.

Modeling Naval Mine Warfare with Machine Learning Algorithms

Modeling Naval Mine Warfare with Machine Learning Algorithms

Barriers to wildlife movement in straits: Problematizing habitat connectivity across marine ecosystems

The innovative development of the legal regime of straits has prevented the erection of ‘sovereignty-barriers’ to the movement of humans in and above straits. However, it overlooks to a great extent the significance of straits for marine organisms and birds. This article examines if it is necessary to supplement the legal regime of straits with rules that would allow circumnavigating ‘sovereignty-barriers’ also for wildlife movement considering the obligation to protect and preserve the marine environment. The main users of straits are not humans, but rather marine species. They rely on straits for moving from one ecosystem to another. That perspective to straits shifts the emphasis away from anthropocentric connectivity. It raises a question about the need to update the current navigation-oriented legal regime of straits with new wildlife-centric rules. This implies an additional scrutiny on human activities that have a significant negative effect on marine organisms and the fragile marine environment of straits. A wildlife-centred approach enables to reconsider the appropriateness of some human uses of the seas that are environmentally hazardous, but still relatively commonplace in straits. It is possible to facilitate the unimpeded movement of marine species through straits by the prohibition of some detrimental maritime practices that have a reasonable alternative. Such practices include, e.g., the detonation of naval mines in clearance operations, the construction of such causeways that are impassable for marine species, and the use of overhead power lines in straits. In addition, limits could be set to the use of sonars and to the speed of ships in straits.

Automatic Target Recognition for Mine Countermeasure Missions Using Forward-Looking Sonar Data

The detection of objects on the seafloor is a complex task. The domain of the detection and classification of naval mines is additionally complicated by the high risk nature of the task. Autonomous underwater vehicles (AUVs) have been used in naval mine countermeasures (MCM) operations to search large areas using sensors such as sidescan or synthetic aperture sonars. These sensors generally have a high coverage rate, while sacrificing spatial resolution. Conversely, sensors with higher resolution but lower coverage (such as forward-looking sonars and electro–optical cameras) are employed for the later classification and identification stages of the MCM mission. However, to autonomously execute a target reacquisition mission, it is important to be able to collect and process data automatically and, in near real time, onboard an AUV. For this purpose, an automatic target recognition (ATR) system is required. This article proposes an ATR, which can be used onboard an autonomous vehicle, capable of detecting mine-like objects in forward-looking sonar data. The ATR combines a detector and a classifier, based on convolutional neural network models, with a probabilistic grid map that filters out false positives and combines reported detections at nearby locations. A strategy, combining a survey pattern with target-mapping maneuvers automatically activated by the ATR, has been designed to maximize the performance of this ATR. The whole system has been tested in simulation as well as using data from previous MCM exercises, the results of which are presented here.

Study of the application of PCM to thermal insulation of UUV hulls using Network Simulation Method

The Unmanned Underwater Vehicles (UUV) designed for the detection and neutralization of naval mines are characterized by their high requirements regarding the reduction of the signatures of a vessel (thermal, acoustic, magnetic, etc.), all of them must be reduced in order not to be detected by the mines during the mission. This research work focuses on the reduction of the thermal signature transmitted by the UUV hull, where the use of phase change materials (PCM) is proposed as thermal insulation, placing it between the internal heat source of the UUV and the pressure hull, with the aim of drastically increasing the time in which the external face of the hull of the UUV is within a range of 3 °C and 5 °C temperature increase, allowing it to perform its mission without being detected by the thermal sensors of current naval mines. The simulation will be carried out using the Network Simulation Method for the resolution of the governing equations, which will allow the optimization of the necessary insulation thickness according to the required mission profile. In addition, it is proposed an expression that relates the PCM thickness and the time needed to reach a certain temperature increase.

Advanced Layered Composite Structures for Underwater Acoustic Applications

The detection of underwater objects is one of the most critical technologies, and there have been constant efforts for developing sophisticated sonar systems in naval warfare. Against such efforts, the countermeasure of hiding underwater vehicles, equipment and weapons is another technological challenge. One of the effective countermeasures against sonic detection for the submarines and other underwater objects, such as naval mines, is to employ composite/hybrid materials to prevent ease of detection. Geometrical forms, shapes and layers, along with the tuning of the acoustical impedance, lead to a considerable decrease of the sonar signals via absorption of the sonic waves. In this study, an original and novel design of multi-layered composite/hybrid structure was developed and underwater acoustic testing procedures of reflection, transmission and scattering were applied in 80 kHz100 kHz frequency range. The findings obtained in this study showed that the multi-layered composite/hybrid materials with porous structure possess much lower values in millivolt than steel plates and might be potential candidates as covering and/or casing materials for underwater mines to reduce the acoustical signature against detection and identification.

4차 산업혁명 신기술로 무장한 기뢰위협과 우리의 대응방안

4차 산업혁명 신기술로 무장한 기뢰위협과 우리의 대응방안

‘Among the faded lines of the Combat Leaflet...’. Yury Inge

The article is dedicated to the pre-war poet Yury Inge, who was killed at the very start of the German invasion of the USSR. A war correspondent during the Winter War (1939–1940), Inge joined the newspaper Krasnoznamyonniy Baltiyskiy Flot in 1941 at its headquarters at the new Soviet naval base in Tallinn. Inge took part in the so-called Tallinn disaster, a tragedy yet to be fully explained: the Soviets lost two-thirds of their Baltic Fleet ships during evacuation to Kronstadt. Inge was leaving on the icebreaker Valdemārs, when it was sunk by a naval mine placed by the Soviet military just days before. A witness account describes the poet, wearing a long black naval coat and equipped with a gas mask and a pistol, helping women and children into a lifeboat, while remaining on board of the damaged ship the entire time. Inge died before reaching his 36th birthday. The article offers a first estimation of the tragedy’s scale and lists all literary workers attached to the Baltic Fleet who met their end on the 28th–29th of August, 1941.

A Simple Superposition Formulation to Predict the Underwater Electric Potential Signature of Naval Vessels

The underwater electric potential (UEP) signature is an electric signal, which can be exploited by naval mines to be utilized as a possible trigger indicator and may cause severe damage to the vessel and the onboard crew. Hence, knowing the UEP signature as exactly as possible can help to evaluate a possible risk of the vessel being detected by naval mines or if the UEP signature is within a noncritical region. As the UEP signature differs for changes of the corrosion protection system, the UEP signature is usually unknown for new conditions. In this work, we present a simple mathematical formulation to predict the UEP signature based on the mere use of a single reference UEP signature, and the corresponding currents, which are excited by the impressed current cathodic protection (ICCP) system. With this methodology, deviations below 10% between the maximum of the simulated UEP signature and the predicted UEP signature can be achieved, even in the presence of the nonlinear corrosion process. Furthermore, a corrosion protective coating of the propellers can significantly reduce the influence of the nonlinear corrosion process on the total UEP signature to improve the prediction accuracy of the superposition formulation as presented in this work.

Classification and Localization of Naval Mines With Superellipse Active Contours

In this paper, an approach for the classification and localization of geometric shapes, e.g., man-made objects or different types of geological features, in sonar images is presented. It is applied to a concrete application case, namely the detection and classification of naval mines. The approach consists of three steps. In the first step, the sonar image is segmented by a new active contours algorithm. To deal with the significant noise on sonar images, the assumption is used that the segmenting contours of highlight and shadow areas of objects are geometric shapes that can be described by superellipses. It is shown here that this superellipse constraint, which can cover a wide range from box-shaped to round objects, can directly be incorporated into an active contours method without an additional edge framework. In addition to its robustness to noise, our superellipse-driven active contours approach has the advantage that it is adaptable to the intensity distribution properties of sonar images. The second step consists of the actual classification including a pose estimation using a standard naive Bayes classifier on the superellipse parameters that are computed by the segmentation in the first step. Robustness is further boosted in a novel third step in which the classification is verified in a top-down process. Based on the results of the bottom-up processes, i.e., the segmentation in step one and the pose estimation from the superellipse parameters plus the class estimation by the classifier in step two, it is possible to simulate what the input sonar image should look like if the results are correct. If this model-based top-down simulation is similar to the original sensor image, the classification result is accepted; otherwise it is rejected. To this end, different measures are compared to compute the similarity between the real sensor image and the anticipated image generated from the classification and localization hypothesis. Finally, our approach is evaluated with a challenging real-world data set of 213 synthetic aperture sonar sidescan images from sea trials with mock-up mines.

Ship’s de-perming process using coils lying on seabed

A ship built from ferromagnetic steel disturbs the uniformity of the Earth’s magnetic field. Changes of ship’s signature are due to the magneto-mechanical interaction of the hull with the Earth’s magnetic field. The ship’s magnetic field can be detected by a magnetic naval mine. For this reason, the vessel has to be demagnetized. There are several methods of ship’s de-perming. The results of experimental and computer simulations of the ship’s de-perming process using coils lying on the seabed are presented in this paper. The simulation of the de-perming process with a hysteresis model of ship’s steel was carried out in Opera3d 18R2. The laboratory experiments were carried out using a physical ship’s model, several Helmholtz coils, magneto-resistive sensors, etc. The experiments and computer simulations have shown that ship’s de-perming with coils lying on the seabed is possi

Transmission of images by unmanned underwater vehicles

As an acoustic communications medium, water is characterized by frequency dependent attenuation, short range, very low bandwidth, scattering, and multi-path. It is generally difficult to acoustically communicate even terse messages underwater much less images. For the naval mine counter-measures mission, there is value in transmitting images of mine-like objects, acquired by side-scan sonar on-board unmanned underwater vehicles, to the above-water operator for review. The contribution of this paper is a methodology and implementation, based on vector quantization, to compress and transmit snippets of side-scan sonar images from underway unmanned underwater vehicles to an operator. The work has been validated through controlled indoor tank tests and several at-sea trials. The fidelity of the received images is such that trained operators can recognize targets in the received images as well as they would have in the original images. Future work investigates machine learning to improve the compression basis and psycho-visual studies for the specialized skill of feature recognition in sonar images.

Synthetic Aperture Sonar Track Registration With Motion Compensation for Coherent Change Detection

The capability to detect changes in an underwater scene has many applications, including environmental monitoring, surveillance of strategic maritime waterways, and naval mine countermeasures. This paper examines the automated detection of changes in repeat-pass synthetic aperture sonar (SAS) imagery by exploiting the loss of phase coherence caused by differences in the scene. A renavigation method based on track registration is developed for performing the coregistration of images. The method first determines the corrections to be applied to the repeat-pass navigation data by optimizing a linear track model using the estimated across-track pixel displacements. A second optimization is then performed using the along-track pixel displacements to determine a velocity correction for each ping location of the repeat-pass image to compensate for residual motion errors. The corrected navigation solution is then used to rebeamform the repeat-pass image onto the same focal points as the reference image. The method is demonstrated on a pair of repeat-pass SAS images acquired using the AquaPix INSAS2 sonar, where it is shown that it is not necessary to have access to raw element data to coregister images accurately enough for coherent change detection requirements. This technique is then applied to the second data set obtained using the HISAS 1030 sonar for the purpose of comparing both coherent and noncoherent (amplitude-only) approaches to change detection in scenes with low and high clutters. False alarms caused by the acoustic shadows of objects in high-clutter areas are mitigated using the single-pass interferometric coherence as a reference mask. The results show the successful use of the repeat-pass coherence to detect changes between SAS images with temporal baselines of several days on scenes consisting of mud, gravel, and sand, and demonstrate that a coherent approach is capable of detecting large-scale differences (caused by the introduction or removal of targets) as well as subtle scene changes that are not detectable using noncoherent methods.