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This paper presents the results of research on the accuracy assessment of the positioning of a swarm of underwater vehicles based on hydroacoustic measurements made with respect to four surface vehicles under the time difference of arrival (TDOA) method. The assessment consisted of the estimation of accuracy parameters for determining the position of an underwater vehicle in relation to surface vehicles forming a so-called moving geometrical measurement structure (MGMS) in the following shapes: square, rectilinear, triangular, and three-pointed. This demonstrated that MGMS makes it possible to estimate the relative position of underwater vehicles in a swarm with an accuracy of 2.1 m (RMS) over an area of approx. 1000 m2 and approx. 3.0 m (RMS) over an area of approx. 1600 m2. The most favourable MGMS shapes include three-pointedwhile maximising the size of the positioning area, where the positioning accuracy should not exceed 3.0 m (RMS)—and rectilinear—while maximising the size of the positioning area, where the positioning accuracy should not exceed 10.0 m (RMS). [ABSTRACT FROM AUTHOR]

The research consisted of simulating the movement of a single vehicle in relation to the swarm leader on a square-shaped path, taking into account measurement errors characteristic of typical cheap navigation devices and the hydroacoustic system. The research showed that these methods allow for estimating position coordinates with an accuracy of about 0.5 m (RMS) in the case of a calibrated navigation system and about 3.6 m (RMS) in the case of a non-calibrated navigation system. It also showed that it can provide a higher accuracy of estimating position coordinates in terms of abeam angles of the swarm leader (relative bearing equal to approximately ±90°), as well as while ensuring minimizing systematic errors values and proper estimation of mean errors values concerning course and speed measurements. [ABSTRACT FROM AUTHOR]

The paper provides a description of a method of drafting route plan templates on the basis of AIS (automatic identification system) historical data. The first section features a brief background on the problem of drafting route plan templates in the light of international regulations. The main section contains a description of the methods and tools used for processing AIS data into a GRID reference system: ship traffic intensity, average COG (course over ground) and average SOG (speed over ground) as well as route plan templates. The final section includes a presentation of the research method and an analysis of the results, conducted on the basis of maps with charted paths of drafted route plan templates. The summary constitutes a synthesis of general conclusions, the advantages and disadvantages of the solution as well as areas for further research to enhance the solution. [ABSTRACT FROM AUTHOR]

The geometric distribution of navigational aids is one of the most important elements to be taken into account in the planning of maritime terrestrial navigation systems. It determines to a large extent the capability of vessels to obtain high-precision position coordinates. Therefore, the optimisation of their location is a key element at the planning stage, in particular on port approach fairways. This article attempts to use computer simulation methods to assess the positioning accuracy of a vessel that follows a constant course and speed on a port approach fairway. The analysis uses a technique based on the Extended Kalman Filter (EKF) Two-Dimensional (2D) Range-Bearing Simultaneous Location and Mapping (SLAM) method. In the simulation experiment conducted, the research object determined its position based on bearing and distance to fixed position beacons, which changed their locations in subsequent passages of the vessel. A geometrically optimal configuration of the terrestrial navigation marking system guaranteeing the highest positioning accuracy was identified as a result of the deliberations. The study analysed more than 20,000 cases of different configurations (locations) of the fixed position beacons, demonstrating that the adopted algorithm can be used successfully in the planning of their deployment in the context of ensuring minimum accuracy requirements for the positioning of navigational signs on port approach fairways and under restricted conditions by navigational marking services, as set out in International Maritime Organization (IMO) Resolutions A915 (21) and A953(22). [ABSTRACT FROM AUTHOR]

A research focused on development of numerical model of a sea area destined for a motion simulator of an Autonomous Biomimetic Underwater Vehicle (ABPP) is presented in the paper. There are purpose, construction and functionality of the ABPP motion simulator generally characterized in the introduction. The first part contains description of a method of creating the sea area model based on the data included in the Electronic Navigational Chart (ENC). A method of displaying the sea area model in the ABPP motion simulator, with a use of the Open GL graphic library, is described in the second part. Finally, there are conclusions drawn from the executed research given at the end. [ABSTRACT FROM AUTHOR]

The article describes a study of problem of estimating the position coordinates of Autonomous Biomimetic Underwater Vehicle (ABUV) using two methods: dead reckoning (DR) and extended Kalman filter (EKF). In the first part of the paper, navigation system of ABUV is described and scientific problem with underwater positioning is formulated. The main part describes a way of estimating the position coordinates using DR and EKF and a numerical experiment involving motion of ABUV along the predetermined test distance. The final part of the paper contains a comparative statistical analysis of the results, carried out for assessing the accuracy of estimation of the position coordinates using DR and EKF methods. It presents the generalized conclusions from the research and the problems relating to the proper placement of the components of the system measuring distances. [ABSTRACT FROM AUTHOR]

This paper summarises research that evaluates the precision of determining a ship's position by comparing an omnidirectional map to a visual image of the coastline. The first part of the paper describes the equipment and associated software employed in obtaining such estimates. The system uses a spherical catadioptric camera to collect positional data that is analysed by comparing it to spherical images from a digital navigational chart. Methods of collecting positional data from a ship are described, and the algorithms used to determine the statistical precision of such position estimates are explained. The second section analyses the results of research to determine the precision of position estimates based on this system. It focuses on average error values and distance fluctuations of position estimates from referential positions, and describes the primary factors influencing the correlation between spherical map images and coastline visual images. [ABSTRACT FROM AUTHOR]

This article describes studies that evaluate the accuracy of measuring a ship's heeling angle with an inclinometer. It does so by comparing inclinometer readings with benchmark measurements made with the optical method. The first part of the article describes the measurement station used for gathering measurement data. This station included an inclinometer and a CCD camera, and was used to process digital images incorporating a horizon line to indicate the ship's heeling angle. The second part of the article describes the data gathering process carried out on a ship at sea. The final part describes a statistical analysis which compares the angular measurements based on an inclinometer with simultaneous optical benchmark measurements. [ABSTRACT FROM AUTHOR]

The paper presents the selected results of the international project called Nextprop, carried out in the framework of the European Defence Agency, which main goal was to examine elastic polymer propellers. The article includes the results of the comparative analysis in terms of the noise produced by two propellers: (1) the classical one made from Nickel Aluminium Bronze (NAB) and (2) the novel elastic counterpart manufactured from polyamide. The measurements were taken in the CTO cavitation tunnel in Gdańsk, Poland. The obtained results allow the following highlights to be formulated: the novel flexible propellers seem to be a promising solution for the new ships, especially in terms of energetic efficiency and produced noise, i.e. lower sound pressure level has been obtained for the new polymer propeller and larger advance speed for the same rotational speeds has been received for the new propeller compared to the classical metal counterpart. At the beginning, the introduction with the results of state-of-the-art analysis is presented. Then, the description of the measurement stand and examined propellers with seizing conditions is included. Next, the obtained results are illustrated and discussed. At the end, the conclusions with the draft of the future research are presented. [ABSTRACT FROM AUTHOR]

This paper presents a dynamic hyperboloidal mapping model aimed at building image of electronic navigational chart which constitutes an equivalent to that obtained from a hypercatadioptric camera system. In the 1st part, space and three reference frames located in it are defined. These are: the observer frame and horizontal topocentric frame considered secondary (both connected with water-surface platform), and the geocentric frame, primary one. The 2nd part provides description of a way of interconnection between the observer frame and horizontal topocentric one as well as of determination of their location in relation to the geocentric reference frame, depending on course and position of water-surface platform. In the final part is presented a model of panoramic image mapping in the observer reference frame and principles of generating ENC image by using dynamic hyperboloidal mapping. Finally, conclusions indicating possible applications of the developed model are presented. [ABSTRACT FROM AUTHOR]

The process of the ships docking, especially very large ships, is an very risky operation in confined and busy port waters. The similar difficult is the task to pass along any channel, river, strait or similar water road. The basic difficulty causes maneuvering with the great mass of the ship in situation of small space to maneuvers, the large inertia of the object and poor maneuvering properties at small speeds occurring in such circumstances. An additional factor, which make this task more difficult is the influence of the wind and the sea current on the hull of the inert ship as well as consequences of the limited visibility. The bad weather can cause the necessity to delay the maneuver. However this joins with heavy costs. An alternative is usage of systems supporting this process. In this paper nowadays accessible systems for augmentation the docking and harbor navigation are analysed. There are: shore based (active or passive) and ship based (active). This paper is prepared in the frame of Bonus project call 2012 'The Captain Assistant system for Navigation and Routing during Operations in Harbor'. [ABSTRACT FROM AUTHOR]

The following article presents researches aimed at the evaluation of precision in determining a ship's position through comparing a omnidirectional map image to a real vision image of the coast line. The first part establishes the thesis and preparatory forms in conducting the research. It also presents designed and built equipment including a research tool software. A system equipped with a spherical catadioptric camera that aids data collection on board ship designated to processing and analyzing data collected on board in connection with the spherical images of an electronic navigational chart with a software module. The second part explains procedures followed in conducting the research. The foreword note explains the procedure in data collection aboard a ship maneuvering in the port after which the algorithm for position placement and precise parametrical count was presented. The concluding part shows analyses of obtained research result. It bears a performance on the evaluation of precision at determining position. As a measure, an average error value and distance fluctuation of obtained position from referential position. As our conclusion, primary agents having rudimentary influence on the quality of correlating spherical map image to coastline visual image were characterized. [ABSTRACT FROM AUTHOR]

The Paper presents the optical method of fixing the off-shore objects positions from the land. The method is based on application of two reference points, having the geographical coordinates defined. The first point was situated high on the sea shore, where also the camera was installed. The second point was intended for use to determine the topocentric horizon plane and it was situated at the water-level. The first section of the Paper contains the definition of space and disposed therein reference systems: connected with the Earth, water-level and the camera system. The second section of the Paper provides a description of the survey system model and the principles of the Charge Coupled Device - CCD array pixel's coordinates (plate coordinates) transformation into the geographic coordinates located on the water-level. In the final section there are presented the general rules of using the worked out method in the optical system. [ABSTRACT FROM AUTHOR]

This article presents the concept of algorithm A* functioning in a navigation system equipped with electronic navigational chart for autonomous planning the shortest and safest route crossing an offshore unmanned vehicle "Edredon". The first part describes the general technical architecture and functionality of the vehicle's navigation system. In the second part shows in detail the modules of the system responsible for the planning of the road and how to implement them in the A* algorithm. The third part describes the proper operation of testing whether the A* algorithm in the navigation system, while the task of planning the route of the autonomous vehicle. Final part is a discussion of the results obtained from tests carried out in order to evaluate the applicability of the A* algorithm for route planning in autonomous navigation systems. [ABSTRACT FROM AUTHOR]

Evaluation of accuracy of position coordinates' determination in respect to floating marks, with free adjustment method applied, has been a target of the paper. General theory of geodesic adjustment - classical one based on least squares method and free adjustment - is presented in its first part. Main part contains description of the research. It was conducted based on geometric navigational structure which elements had been formed by beacons placed in the Bay of Gdańsk. It consisted in simulating results of measurements made in respect to marks of this structure (bearings and distances) and calculating the position coordinates based on them, as well as its accuracy. The calculations were made with the method of classical geodesic adjustment and free adjustment applied. Discussion about obtained results of the research and general conclusions are given in the ending part of the article. [ABSTRACT FROM AUTHOR]

Mounting offshore renewable energy installations often involves extra risk regarding the safety of navigation, especially for areas with high traffic intensity. The decision-makers planning such projects need to anticipate and plan appropriate solutions in order to manage navigation risks. This process is referred to as "environmental impact assessment". In what way can these threats be reduced using the available Automatic Identification System (AIS) tool? This paper presents a study of the concept for the methodology of an a posteriori vessel traffic description in the form of quantitative and qualitative characteristics created based on a large set of historical AIS data (big data). The research was oriented primarily towards the practical application and verification of the methodology used when assessing the impact of the planned Offshore Wind Farm (OWF) Baltic II on the safety of ships in Polish Marine Areas, and on the effectiveness of navigation, taking into account the existing shipping routes and customary and traffic separation systems. The research results (e.g., a significant distance of the Baltic II from the nearest customary shipping route equal to 3 Nm, a small number of vessels in its area in 2017 amounting to only 930) obtained on the basis of the annual AIS data set allowed for an unambiguous and reliable assessment of the impact of OWFs on shipping, thus confirming the suitability of the methodology for MREI spatial planning. [ABSTRACT FROM AUTHOR]

Undoubtedly, Low-Altitude Unmanned Aerial Vehicles (UAVs) are becoming more common in marine applications. Equipped with a Global Navigation Satellite System (GNSS) Real-Time Kinematic (RTK) receiver for highly accurate positioning, they perform camera and Light Detection and Ranging (LiDAR) measurements. Unfortunately, these measurements may still be subject to large errors-mainly due to the inaccuracy of measurement of the optical axis of the camera or LiDAR sensor. Usually, UAVs use a small and light Inertial Navigation System (INS) with an angle measurement error of up to 0.5 ∘ (RMSE). The methodology for spatial orientation angle correction presented in the article allows the reduction of this error even to the level of 0.01 ∘ (RMSE). It can be successfully used in coastal and port waters. To determine the corrections, only the Electronic Navigational Chart (ENC) and an image of the coastline are needed. [ABSTRACT FROM AUTHOR]

This article presents research on assessing the accuracy of ship position determination based on observations of radar echoes of navigation marks identified in an Electronic Navigational Chart (ENC). The accuracy analysis of the simulated radar positioning in relation to navigation marks the validity of the research. Position accuracy on the approach fairways was better than 6.5 m (RMS). A specially prepared measuring system made it possible to conduct tests based on radar images. In subsequent stages of the research, the association of extracted characteristic radar echoes with navigation marks found in an ENC was made. Then, in order to eliminate significant values of measurement errors and erroneous identification of navigation marks, geodetic adjustment was applied. The obtained position accuracy equal to 34.1 m (RMS) provides a premise to state that the method can be adopted for autonomous navigation systems which are alternatives to Global Navigation Satellite System (GNSS). • Novel method for navigation in Global Navigation Satellite System denied environment. • Automating bearing and distance measurements relative to navigation marks. • Data fusion from Electronic Navigational Chart (ENC) and radar system. • Positioning accuracy higher than 100m (P = 95%) in coastal zone using radar. [ABSTRACT FROM AUTHOR]

A market for small drones is developing very fast. They are used for leisure activities and exploited in commercial applications. However, there is a growing concern for accidental or even criminal misuses of these platforms. Dangerous incidents with drones are appearing more often, and have caused many institutions to start thinking about anti-drone solutions. There are many cases when building stationary systems seems to be aimless since the high cost does not correspond with, for example, threat frequency. In such cases, mobile drone countermeasure systems seem to perfectly meet demands. In modern mobile solutions, frequency modulated continuous wave (FMCW) radars are frequently used as detectors. Proper cooperation of many radars demands their measurements to be brought to a common coordinate system—azimuths must be measured in the same direction (preferably the north). It requires calibration, understood as determining constant corrections to measured angles. The article presents the author's method of fast, simultaneous calibration of many mobile FMCW radars operating in a network. It was validated using 95,000 numerical tests. The results show that the proposed method significantly improves the north orientation of the radars throughout the whole range of the initial errors. Therefore, it can be successfully used in practical applications. [ABSTRACT FROM AUTHOR]

The paper presents the results of research on assessing the accuracy of angular position measurement relative to the sea horizon using a camera mounted on an unmanned bathymetric surveying vehicle of the Unmanned Surface Vehicle (USV) or Unmanned Aerial Vehicle (UAV) type. The first part of the article presents the essence of the problem. The rules of taking the angular position of the vehicle into account in bathymetric surveys and the general concept of the two-camera tilt compensator were described. The second part presents a mathematical description of the meters characterizing a resolution and a mean error of measurements, made on the base of the horizon line image, recorded with an optical system with a Complementary Metal-Oxide Semiconductor (CMOS) matrix. The phenomenon of the horizon line curvature in the image projected onto the matrix that appears with the increase of the camera height has been characterized. The third part contains an example of a detailed analysis of selected cameras mounted on UAVs manufactured by DJI, carried out using the proposed meters. The obtained results including measurement resolutions of a single-pixel and mean errors of the horizon line slope measurement were presented in the form of many tables and charts with extensive comments. The final part presents the general conclusions from the performed research and a proposal of directions for their further development. [ABSTRACT FROM AUTHOR]

This study analyses the impact of initial conditions on the results of numerical simulations of the fan load with underwater detonation and simultaneously typical harmonic loads from the operating device. It was shown that different initial conditions affect both displacement and velocity results. Furthermore, significant differences were indicated when comparing the results with devices without harmonic loads. The results indicate the need for more detailed analyses at the initial stage of modelling the impact resistance of devices planned for ship installation. [ABSTRACT FROM AUTHOR]

Video image processing and object classification using a Deep Learning Neural Network (DLNN) can significantly increase the autonomy of underwater vehicles. This paper describes the results of a project focused on using DLNN for Object Classification in Underwater Video (OCUV) implemented in a Biomimetic Underwater Vehicle (BUV). The BUV is intended to be used to detect underwater mines, explore shipwrecks or observe the process of corrosion of munitions abandoned on the seabed after World War II. Here, the pretrained DLNNs were used for classification of the following type of objects: fishes, underwater vehicles, divers and obstacles. The results of our research enabled us to estimate the effectiveness of using pretrained DLNNs for classification of different objects under the complex Baltic Sea environment. The Genetic Algorithm (GA) was used to establish tuning parameters of the DLNNs. Three different training methods were compared for AlexNet, then one training method was chosen for fifteen networks and the tests were provided with the description of the final results. The DLNNs were trained on servers with six medium class Graphics Processing Units (GPUs). Finally, the trained DLNN was implemented in the Nvidia JetsonTX2 platform installed on board of the BUV, and one of the network was verified in a real environment. [ABSTRACT FROM AUTHOR]

This article covers research on an innovative propulsion system design for a Biomimetic Unmanned Underwater Vehicle (BUUV) operating at low speeds. The experiment was conducted on a laboratory test water tunnel equipped with specialised sensor equipment to assess the Fluid-Structure Interaction (FSI) and energy consumption of two different types of propulsion systems. The experimental data contrast the undulating with the drag-based propulsion system. The additional joint in the drag-based propulsion system is intended to increase thrust and decrease energy input. The tests were conducted at a variety of fins oscillation frequencies and fluid velocities. The experiments demonstrate that, in the region of low-speed forward movement, the efficiency of the propulsion system with the additional joint is greater. [ABSTRACT FROM AUTHOR]