Global and local path (GPP, LPP) planning is very actively researched for different vessels and manning levels. To employ planning algorithms or workflows, an environment model must be created, which is not commonly based on Electronic Navigational Chart (ENC), although it is the official and standardized representation of maritime environment. ENCs are used in Electronic Chart Display and Information System (ECDIS), a component of an Integrated Navigation System (INS), the software platform fusing ECDIS, radar, sensor data and functions including route planning for which GPP can be considered as a part thereof. ENCs were created primarily for human interpretation, however with intended usage not solely for navigation. Closed and proprietary navigational and research software, ENC format limitations, scarce availability of free ENC file formats and complex usage outside of regulated frameworks contribute to limited number of ENC based GPP research approaches, usually based on single or few ENC objects. Therefore, the purpose of this study was to create an open-source methodology based on spatially extended object-relational database, programming languages and libraries with geographic information system to manage ENC objects used for static environment modelling and GPP applicable in INS or broader context. We created the navigable area and environment model using ENC objects and hexagonal hierarchical grids from Uber's H3 Hexagonal Hierarchical Geospatial Indexing System library. For evaluation, we used ENC objects from different usage bands and scales for area between the ports of Savannah and Charleston in the USA with results confirming the open-source methodology applicability, along with possibilities for further research and development.

The characterization of ship routes and route similarity measurement based on Automatic Identification System (AIS) data are topics of various scientific interests. Common route research approaches use available AIS identifiers of ship types. However, assessing route and similarity profiles for individual fleets requires collecting data from secondary sources, dedicated software libraries or the creation of specific methods. Using an open-source approach, public AIS and ship data, we evaluate route characteristics for the container ships of a single fleet in a six-month period, calling on two selected ports of the shipping line on the USA East Coast. We evaluate the routes in terms of length, duration and speed, whereas for the similarity measurement we employ the discrete Fréchet distance (DFD). The voyage length, duration and average speed distributions were observed to be moderately positive (0.77), negative (−0.62), and highly positively skewed based on the adjusted Fisher–Pearson coefficient of skewness (1.23). The most similar voyages were from the same ships, with the lowest discrete Fréchet distance similarity value (0.9 NM), whereas 2 different ships had the most dissimilar voyages, with the highest DFD value (14.1 NM). The proposed methodology enables assessment of similarities between individual ships, or between fleets.

In past years, numerous global path planning methods have been researched and applied in maritime surface navigation. Regardless of intended usage for either decision-support in manned, or autonomous vessel navigation, path planning should generate a safe and efficient route. However, prior to route generation, static maritime environment representation must be created first. Whether it is transformed in to discrete or continuous form, common approach is to use Electronic Navigational Charts (ENCs) as a basis for maritime environment representation. Nevertheless its origins, ENCs still adhere to inherited data generalisations and simplifications to be comprehensible for human navigators. This leads to limitations when considering path planning and spatial resolution at different chart scales. Furthermore, when generating the representation and path, uncertainty must be considered since the quality and accuracy of chart data varies. Although these topics have been addressed separately in their respective domains, their relations have not been researched in detail. The aim of the proposed paper is the review of electronic navigational charts, environment representation and common global path planning approaches’ relations. Forthcoming standards and technologies, such as usage of high-density charts, are presented and discussed as well.

Global and regional positional accuracy assessment is of the highest importance for any satellite navigation system, including the Global Positioning System (GPS). Although positioning error can be expressed as a vector quantity with direction and magnitude, most of the research focuses on error magnitude only. The positional accuracy can be evaluated in terms of navigational quadrants as further refinement of error distribution, as it was shown here. This research was conducted in the wider area of the Northern Adriatic Region, employing the International Global Navigation Satellite Systems (GNSS) Service (IGS) data and products. Similarities of positional accuracy and deviations distributions for Single Point Positioning (SPP) were addressed in terms of magnitudes. Data were analyzed during the 11-day period. Linear and circular statistical methods were used to quantify regional positional accuracy and error behavior. This was conducted in terms of both scalar and vector values, with assessment of the underlying probability distributions. Navigational quadrantal positioning error subset analysis was carried out. Similarity in the positional accuracy and positioning deviations behavior, with uneven positional distribution between quadrants, indicated the directionality of the total positioning error. The underlying distributions for latitude and longitude deviations followed approximately normal distributions, while the radius was approximated by the Rayleigh distribution. The Weibull and gamma distributions were considered, as well. Possible causes of the analyzed positioning deviations were not investigated, but the ultimate positioning products were obtained as in standard, single-frequency positioning scenarios.

Creating an efficient and safe voyage plan is a complex and challenging task. Compliance with safe mandatory voyage planning procedures must be considered alongside shortest distance, sailing time and efficiency. Mentioned factors reflect on decisions in voyage appraisal, planning, execution and monitoring. Decisions in all voyage stages are further influenced by navigational knowledge and experience of those involved in the actual planning. Subjective interpretation, quality of used sources and uncertainties can result in different voyage plan outcomes. Research in weather routing and quality and assessment of hydrographic data have enabled multi-criteria and multi-objective voyage planning approaches. Usage of Electronic Chart Display and Information System (ECDIS) voyage planning features and advanced third-party solutions (including improved GNSS solutions) have improved the voyage planning process on-board. For a safe voyage planning, determination of safety distances to non-navigable areas or dangers is essential. Furthermore, uncertainty must be assessed for all elements of voyage planning. Moreover, the route has to be adaptable to forecasted or present environmental conditions. The aim of this paper is to present the concept of safety distance determination as a function of the adaptive planning process in coastal navigation. The concept integrates all relevant parameters influencing the decisions of the navigational planning task in an adaptive way, with the final output subject to pre-defined limit values. Ship particulars, hydrographic data accuracy and reliability, hydrographical and meteorological conditions, etc. set the basis for the safety distance determination. The concept is further enhanced with information on current and forecasted environmental conditions prevailing in the area of interest.

For a long time, Inmarsat satellite system was the only maritime mobile satellite service provider when Global Maritime Distress and Safety System (GMDSS) is concerned.This satellite system has diff erent generations of its satellites providing a wide range of services and applications.In 2018, its services related to the GMDSS have migrated to a newer generation of satellites.This satellites' services migration is systematically discussed and analysed in this paper in order to familiarize the readers with its eff ects on the safety of navigation.Furthermore, Inmarsat system announced a new service called Inmarsat Fleet Safety which will incorporate and provide all functional requirements for the GMDSS which are currently provided by Inmarsat-C and Inmarsat Fleet 77 terminals.However, in 2018 a new satellite system called Iridium has been recognized as a mobile satellite communication services provider in the GMDSS.Accordingly, this system and its capabilities are also introduced and briefl y described in this paper.In addition, authors have discussed impacts of the introduction of the new satellite system as a service provider in the GMDSS and addressed several emphasized issues related to this GMDSS modernization.

The Automatic identification System (AIS) has been mainly designed to improve safety and efficiency of navigation, environmental protection, coastal traffic monitoring simplifying identification and communication. Additionally, historical AIS data have been used in many other areas of maritime safety, economic and environmental research. The probability of the detection of terrestrial AIS signals from space was presented in 2003, following the advancements in micro satellite technology. Through constant development, research and cooperation between governmental and private sectors, Satellite AIS (S-AIS) has been continuously evolving. Advancements in signal and data processing techniques have resulted in an improved detection over vast areas outside of terrestrial range. Some of the challenges of S-AIS technology include satellite revisit times, message collision and ship detection probability. Data processing latency and lacking the continuous real-time coverage made it less reliable for end user in certain aspects of monitoring and data analysis. Recent developments and improvements by leading S-AIS service providers have reduced latency issues. Complementing with terrestrial AIS and other technologies, near real-time S-AIS can further enhance all areas of the global maritime monitoring domain with emerging possibilities for maritime industry.