AIS - Automatic Identification System.
An automatic communication and identification system intended to improve the safety of navigation by assisting in the efficient operation of vessel traffic services (VTS), ship reporting, ship-to-ship and ship-to-shore operations.
Glossary Of Maritime Navigation Related TermsARCS - Admiralty Raster Chart Service. The Admiralty Raster Chart Service (ARCS) provides direct digital facsimile reproduction of Admiralty charts for use in a wide range of electronic navigational systems both at sea and in shore-based applications. Updating is achieved with a minimum of effort. ARCS is global - there are already more than 2900 charts covering the world's major ports and routes. ARPA - Automated RADAR Plotting Aid. A system wherein radar targets are automatically acquired and tracked and collision situations computer assessed and warnings given. BA - British Admirality. BSH - Bundesamt für Seeschiffahrt und Hydrographie. Federal Maritime and Hydrographic Agency of Germany. DGPS - Differential GPS. A form of GPS in which the reliability and accuracy are enhanced by broadcasting a time-varying correction message from a GPS monitoring receiver (Differential Mode) at a known position on shore. The corrections are fed automatically to the GPS receiver on board and used to compute an improved position. directENC SENC format used for the SevenCs products is called directENC. It simplifies and accelerates the access to the ENCs and their handling. Like ECDIS, it works on every platform, no matter whether you use Windows or Unix. The directENC format has been approved by the Federal Maritime and Hydrographic Agency of Germany (BSH). It acknowledged that directENC provides "a complete storage and availability of information content of the ENC data format S-57, Edition 3.1 without changes and losses". This means that directENC can be used officially for distribution of the ENC data. For inland navigation the directENC format now completely realises the InlandECDIS Standard that was agreed upon in May 2001. In this standard the information content of the ENC data format S-57 Edition 3.1 has been supplemented with requirements for inland navigation. Thus it is ensured that by means of InlandECDIS data (charts) produced for ocean navigation can also be viewed on inland navigation vessels. ECDIS - Electronic Chart Display and Information System. The navigation information system which is considered the equivalent of the nautical paper chart, displaying selected information from the chart data base (see ENC, SENC) integrated with data from positional and, optionally, other sensors. By displaying chart contents and optionally other chart related and navigational information ECDIS assists the mariner in route planning and with online position indication in route monitoring. An ECDIS can only be recognised as equivalent to the chart required by Regulation V/20 of SOLAS if it satisfies the yet provisional IMO and IHO specifications. ECS - Electronic Chart System. Generic term for equipment which displays chart data but which is not intended to comply with the IMO performance standard for ECDIS. ECS is intended for use in conjunction with a paper chart. Electronic Chart A very broad term to describe data, software and the electronic system capable of displaying chart information. An electronic chart may or may not be the equivalent of the paper chart required by SOLAS. ENC - Electronic Navigational Chart. The data base, standardised as to content, structure and format, issued for use with ECDIS. The ENC is equivalent to new Editions of paper charts and may contain supplementary nautical information additional to that contained in the paper chart (e.g. sailing Directions). The ENC is a subset of the ENC Data Base developed by the national Hydrographic Authorities. GMDSS - Global Maritime Distress and Safety System. A communication service coordinated worldwide for Distress alerting and promulgation of Maritime Safety Information (MSI). GPS - Global Positioning System. A satellite-based navigation system consisting of a network of 24 orbiting satellites that are eleven thousand nautical miles in space and in six different orbital paths. The satellites are constantly moving, making two complete orbits around the Earth in just under 24 hours. GPS was originally designed and built for military applications. As the system evolved, many persons realised that it has numerous civilian applications as well. By presidential proclamation, Ronald Reagan declared in the early 1980s that GPS would be made available to everyone with the exception that the best accuracy would still be reserved for the military. Since that time, satellites capable of being degraded with SA have been launched regularly. Today, all GPS satellites are capable of and subject to SA degradation. The rationale behind SA is to deny hostile military or terrorist organisations the maximum accuracy benefits of GPS. Another factor affecting GPS accuracy is satellite geometry. Satellite geometry refers to the location of the satellites relative to each other (from the perspective of the GPS receiver). An example: If a GPS receiver is locked onto four satellites and all four of these satellites are in the sky to the north and west of the receiver, satellite geometry is rather poor. In fact, the GPS receiver may be unable to provide a position reading. All the distance measurements come from the same general direction. This means triangulation is poor and the common area where these distance measurements intersect is fairly large (i.e., the area where the GPS receiver thinks our position covers a large space, so pinpoint positioning is not possible). In this scenario, even if the GPS receiver does report a position, accuracy will not be very good maybe off as much as 100-150m. Grade of Chart Official ENC: S-57 data produced according to the IHO ENC Product Specification and issued officially by the authority of a Government authorized Hydrographic Office or other relevant government institution. Derived ENC: S-57 data compatible with the IHO ENC Product Specification and issued by the private sector but derived from an official source provided by authorized Hydrographic Offices or other relevant government institutions. Private ENC: S-57 data produced, issued and packaged by the private sector. HO - Hydrographic Office. A national authority producing the official navigational charts. Most of the maritime countries have got one. IHO - International Hydrographic Organization. Coordinates the activities of national hydrographic offices; promotes standards and provides advice for developing countries in the fields of hydrographic surveying and production of nautical charts and publications. IMO - International Maritime Organization. Formerly called IMCO, the IMO is the specialised agency of the United Nations responsible for maritime safety and efficiency of navigation. ISM-Code - International Safety Management. The International Management Code for the Safe Operation of Ships and for Pollution Prevention (ISM Code) addresses the responsibilities of the people who manage and operate ships and provides an international standard for the safe management and operation of ships and for pollution prevention. The application of the ISM Code should support and encourage the development of a safety culture in shipping. Factors for the successful development of a safety culture include: commitment, values and beliefs. MSI - Maritime Safety Information. Navigational and meteorological warnings, meteorological forecasts, distress alerts and other urgent safety related messages broadcasted to ships. ECDIS update information is considered as MSI. NMEA 0183 - National Marine Electronics Association. The National Marine Electronics Association is a non-profit association composed of manufacturers, distributors, dealers, educational institutions and others interested in peripheral marine electronic occupations. An NMEA standard defines an electrical interface and data protocol for communications between marine instrumentation. The NMEA-0183 standard is 4800 baud and consists of several different ASCII sentences. NMs - Admirality Notices to Mariners. P&TNMs - Preliminary & Temporary Notices to Mariners. RADAR - Radio Detection And Ranging. Raster Chart Format Method of representing all or part of a chart digitally by a matrix-like scheme of pixels or grid points. Charts in raster format are scanned, geo-referenced paper charts. Contrary to the charts in vector format, no additional information may be given to the user. Important functionalities of an ECDIS are not possible with data in raster format. For example it is impossible to do the route controlling automatically. To do it, you require information about depth contours, land areas and so on, which is not available in raster format. Advantages of charts in raster format are: • They are easy to produce. Only paper charts need to be scanned. • They are easy to operate. Panning of charts is faster than for charts in vector format. • People are used to the symbology of raster charts. British Admiralty supplies their ARCS charts in raster format. RENC - Regional ENC Coordinating Centre. In the Worldwide Electronic Navigational Chart Data Base (WEND) it is the IHO network of Hydrographic Offices. It is the regional node being responsible as Issuing Authority for official ENCs and official updates compiled of national ENC data. S-57 IHO Publication No. 57.
IHO Transfer standard for Digital Hydrographic data contains the definition of the exchange format. The object classes and their attributes designed to describe reality and to translate it into a digital data base are defined in the Appendix A. S-52 IHO Special Publication No. 52.
The specification for Chart Content and Display Aspects describes which information is to be displayed by means of chart on the screen and what are the presentation requirements for an ECDIS. S-63 - IHO Data Protection Scheme. The publication “S-63—IHO Data Protection Scheme” describes the recommended standard for the protection of ENC information. It defines security constructs and operating procedures that must be followed to ensure that the data protection scheme is operated correctly and to provide specifications that allow participants to build compliant systems. The S-63 standard is based on the protection scheme developed and operated by Primar and Primar-Stavanger as part of providing their protected ENC service. The Electronic Chart Centre AS and United Kingdom Hydrographic Office were the original contributing organisations. SENC - System Electronic Navigational Chart. The data base which is transformed by ECDIS of the ENC for optimum use and updated by appropriate means. The SENC is the data base that is actually accessed for the display generation and other navigational functions. The SENC contains the equivalent of the up-to-date paper chart. SOLAS - Safety of Life at Sea. Safety of Life at Sea stands for the regulations relating to the safety on board of ships, as defined by the IMO. STCW 95 - Standards of Training, Certification and Watchkeeping for Seafarers. An essential criterion for safe navigation is an adequate manning of vessels with qualified seafarers. The International Convention on Standards of Training, Certification and Watchkeeping for Seafarers (1978) as amended on 7 July 1995 (STCW Convention) set minimum standards for the qualification of seafarers and the issue of Certificates of Competency. UKHO - United Kingdom Hydrographic Office. Usage 1: Overview (fewest Details) 2: General 3: Coastal 4: Approach 5: Harbour 6: Berthing (most Details) Vector Charts A vector is a direct connection between two points, either given as two sets of coordinates (points) or as the direction and distance of one given set of coordinates or a point in a vector space defined by one set of coordinates relative to the origin of a coordinate system. S-57 vector charts are distributed in ISO8211 format or in SENC format. Have a look at the directENC for more details. A vector chart presentation is a method of representing individual chart features digitally as points, lines and polygons described by their coordinates and appropriate code(s). Advantages of charts in vector format are: • Variable zoom in and -out. • Highest accuracy (directENC is capable of a precision of 2 cm on the surface of the earth). • Additional information may be stored direct into the data (route checking, anti grounding a.s.o.). • Rotation of the charts without loss of data is easy to do in comparison with raster charts. Disadvantages are: • High time and production costs in preparing a vector chart. • The performance is not always esthetic but more functional. WEND - Worldwide Electronic Navigational Chart Data Base World Electronic Navigational Chart Database, a model for a distribution network for ENC services to ECDIS compliant shipping developed by the IHO. A common, worldwide network of ENC datasets, based on IHO standards, designed specifically to meet the needs of international maritime traffic using ECDIS which conform to the IMO Performance Standards. |
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