ECDIS v001.000 ENG - CURSUS - 2019 PDF

ECDIS STCW A-II/1, A-II/2, A-II/3 Defensie MARINECOMPONENT Competentiecentrum Marine Ecole Nautique / Nautische School ECDIS 001/000 2 001.000...

ECDIS STCW A-II/1, A-II/2, A-II/3 Defensie MARINECOMPONENT Competentiecentrum Marine Ecole Nautique / Nautische School ECDIS 001/000 2 001.000 ECDIS This curriculum is property of the VDAB© and is a cooperation between: Ecole Nautique / Nautische School Antwerp Maritime Academy VDAB Maritieme Opleidingen contact: contact contact: Leopold Debruynestraat 125 Noordkasteel Oost 6 Lanceloot Blondeellaan 9 8310 Brugge 2030 Antwerpen 8380 Zeebrugge tel. +32 02 44 13183 tel. +32 32 05 64 35 tel. +32 50 59 03 10 [email protected] [email protected] [email protected] Edition Revision Date Reason / Remarks 001 000 01-01-2019 Base document Author(s): L. Baert Wettelijk Depotnummer: Peoplesoft Code: 3 ECDIS 001/000 Required foreknowledge: In order to participate in this course, you should have received some formal navigation and training in the use of instruments. You should also have basic computer skills. Learning objective This course will allow you to use the ECDIS to maintain the safety of navigation through the use of ECDIS and associated navigation systems. Evaluation At the last day of the course there will be a test. The test will take about 4 hours and will consist of a theoretical and a practical part. To succeed a score of 60% is required.. The examination regulations are at your disposal at the front desk. Timetable Day 1 Day 2 Day 3 Day 4 Block 1 Ch1: What is ECDIS Ch11: Integrity of the Ch9: Interfacing & Repetition, navigational solution integration Ch2: history of the theoretical test ECDIS and the Exercise: manual position and electronic chart Ch8: Back-up practical test Ch3: Legal aspects Ch10: Power supply Ch4: Electronic Chart Data Block 2 Familiarisation exercise Exercise: safety Ch15: Route monitoring parameters and Exercise: planning a route alarms in narrow water Block 3 Ch5: Electronic Charts Ch14: Route Planning Exercise: planning a route in narrow water Ch6: Errors in Exercise: planning a displayed data route in open sea Ch7: ECDIS or ECS Block 4 Ch6: Errors in Ch12: Data coverage Ch 16: Human error displayed data and data distribution Exercise: IHO ENC/ECDIS Ch7: ECDIS or ECS Ch13: Loading and date presentation and up-dating data performance checks 4 001.000 ECDIS CONTENTS 1 What is ECDIS................................................................................................................................................. 8 2 History of the ECDIS and the electronic chart................................................................................................ 8 The basic idea........................................................................................................................................ 8 2 ways of producing ctronic charts........................................................................................................ 8 Performance standards – Purpose of ECDIS.......................................................................................... 8 Performance standards - definition ECDIS............................................................................................ 9 Acceptance to meet chart carriage requirements................................................................................. 9 Mandatory carriage of ECDIS................................................................................................................. 9 The ECDIS-mindset.............................................................................................................................. 10 Training................................................................................................................................................ 10 3 Overview legal aspects and requirements................................................................................................... 11 IMO: SOLAS Chart Carriage Requirements.......................................................................................... 11 IMO: SOLAS ECDIS Carriage Requirements.......................................................................................... 12 IMO: Performance Standards for ECDIS.............................................................................................. 12 IMO: training requirements................................................................................................................. 13 IMO, IHO, IEC: Technical Standards and Specifications....................................................................... 13 4 Electronic Chart Data.................................................................................................................................... 15 Raster Data versus Vector Data........................................................................................................... 15 Official Data versus Private Data......................................................................................................... 20 5 Electronic Charts.......................................................................................................................................... 21 Electronic Navigational Charts (ENCs)................................................................................................. 21 IHO Standards for ENCs....................................................................................................................... 21 Raster Navigational Charts (RNCs)....................................................................................................... 27 IHO Standard for RNCs........................................................................................................................ 27 Private Data......................................................................................................................................... 28 6 Errors of displayed data............................................................................................................................... 29 Errors in source data............................................................................................................................ 29 Compilation errors............................................................................................................................... 29 Category of zone of confidence in data (CATZOC or ZOC)................................................................... 29 7 ECDIS or ECS................................................................................................................................................. 31 ECDIS and the Performance Standards................................................................................................ 31 ECDIS Type Approval............................................................................................................................ 31 ECDIS mode of operation.................................................................................................................... 31 ECS mode of operation........................................................................................................................ 34 Electronic charting system awareness................................................................................................ 34 5 ECDIS 001/000 8 Back-up system............................................................................................................................................. 35 IMO back-up requirements................................................................................................................. 35 Dual ECDIS solution............................................................................................................................. 35 Paper chart back-up solution............................................................................................................... 35 Other back-up solutions...................................................................................................................... 36 Fault detection..................................................................................................................................... 36 Troubleshooting.................................................................................................................................. 36 9 Interfacing and integration........................................................................................................................... 37 Connections with mandatory sensors................................................................................................. 37 Connections with other navigational equipment................................................................................ 39 10 ECDIS power supply...................................................................................................................................... 41 11 Integrity of the navigational solution........................................................................................................... 42 Alarms and indicators in ECDIS mode of operation............................................................................. 42 Alarms and indicators in RCDS mode of operation............................................................................. 47 Performance tests............................................................................................................................... 48 12 Data coverage and data distribution............................................................................................................ 49 The Worldwide Electronic Navigational Chart Database (WEND)....................................................... 49 Distribution of ENCs............................................................................................................................. 50 13 Loading and up-dating data.......................................................................................................................... 52 Ordering charts.................................................................................................................................... 52 Loading charts...................................................................................................................................... 52 Recordkeeping..................................................................................................................................... 55 14 Route planning............................................................................................................................................. 56 Creating a new route........................................................................................................................... 56 Creating alternative routes.................................................................................................................. 58 Editing an existing route...................................................................................................................... 58 15 Route monitoring......................................................................................................................................... 59 Display options.................................................................................................................................... 60 Own ship.............................................................................................................................................. 61 Navigational elements and parameters.............................................................................................. 61 ECDIS tools........................................................................................................................................... 62 16 Human error................................................................................................................................................. 63 Risk of over reliance on the system..................................................................................................... 63 Misrepresentation of information....................................................................................................... 63 False interpretation............................................................................................................................. 63 Case studies......................................................................................................................................... 64 17 Port State Control......................................................................................................................................... 66 6 001.000 ECDIS 18 Appendices................................................................................................................................................... 67 Appendix I: IHO ENC/ ECDIS data presentation and performance checks feedback form.................. 67 19 List of abbreviations used............................................................................................................................. 73 20 References.................................................................................................................................................... 74 7 ECDIS 001/000 1 WHAT IS ECDIS ECDIS is an advanced navigation information system for use in ships. ECDIS has been developed to lighten the navigational workload, freeing the mariner for other important navigation related tasks such as maintaining a safe lookout. It is a real-time decision aid which provides the mariner with accurate and reliable information about the ship’s position and its intended movements in relation to charted features. ECDIS will replace paper charts in many ships, providing increased benefits for safety and efficiency. 2 HISTORY OF THE ECDIS AND THE ELECTRONIC CHART THE BASIC IDEA Electronic chart possibilities started being intensively explored from the 1980s, as affordable technology started to become available. Users of terrestrial positioning systems, such as Decca and Loran, had seen the potential of showing position superimposed on map information. So did the developers and early users of satellite positioning systems. During this period basic technology for electronic charting was developed. Unfortunately the available technology could not yet provide affordable systems capable of replacing the use of paper charts. For instance the processor power needed to manipulate large amounts of data was not yet available at a reasonable price, the capacity of disk drives was insufficient to hold a useful number of charts and the display resolution was not sufficient to show chart details at workable scales. 2 WAYS OF PRODUCING CTRONIC CHARTS Technology was advancing at high speed and it became clear that electronic systems with the potential to replace paper charts would become available during the 1990s. By then it was recognized that there were two separate ways of producing electronic charts, namely: 1 by storing and displaying the image of a paper chart in digital format, as a digital photograph of an existing paper chart. This type of chart is known as a raster electronic chart. 2 by storing all the basic information about the charted features as a long list including all positional information of features and objects in coordinates. All objects would be described by vector data instead of point objects: depth contours would be represented by lines and channel separation lanes by areas. This type of chart is known as a vector electronic chart. Although the capabilities of vector charts are far greater than those of raster charts, some Hydrographic Offices favoured a phased introduction of electronic charts: starting with raster charts and eventually progressing to vector charts. This because raster charts are much easier to produce and are identical in look and contents to paper charts, so more familiar in use. This strategy was not universally adopted; full international agreement could not be obtained within IMO. PERFORMANCE STANDARDS – PURPOSE OF ECDIS Instead IMO concentrated on defining performance standards for a system using vector charts: the Electronic Chart Display and Information System or ECDIS. These performance standards were first defined in 1995, in IMO Resolution A.817 (19): Performance standards for electronic chart display and information systems. This Resolution states that “the primary function of the ECDIS is to contribute to safe navigation” and that the “use of ECDIS should reduce the navigational workload as compared to use of paper charts”. 8 001.000 ECDIS PERFORMANCE STANDARDS - DEFINITION ECDIS ECDIS is defined in the IMO Performance Standards as follows: “ELECTRONIC CHART DISPLAY AND INFORMATION SYSTEM (ECDIS) MEANS A NAVIGATION INFORMATION SYSTEM WHICH, WITH ADEQUATE BACK-UP ARRANGEMENTS, CAN BE ACCEPTED AS COMPLYING WITH THE UP-TO-DATE CHART REQUIRED BY REGULATIONS V/19 AND V/27 OF THE 1974 SOLAS CONVENTION, AS AMENDED, BY DISPLAYING SELECTED INFORMATION FROM A SYSTEM ELECTRONIC NAVIGATIONAL CHART (SENC) WITH POSITIONAL INFORMATION FROM NAVIGATION SENSORS TO ASSIST THE MARINER IN ROUTE PLANNING AND ROUTE MONITORING, AND IF REQUIRED DISPLAY ADDITIONAL NAVIGATION RELATED INFORMATION.“ ACCEPTANCE TO MEET CHART CARRIAGE REQUIREMENTS In 2002 SOLAS Chapter V was amended and for the first time included provision for the use of an electronic means of navigation to meet SOLAS chart carriage requirements. MANDATORY CARRIAGE OF ECDIS After the 2005 decision to make the use of ECDIS mandatory on high-speed craft, the IMO in 2009 considered the progress in producing ENCs sufficient, and agreed on a program introducing the compulsory carriage of ECDIS. IMO adopted amendments to SOLAS making ECDIS mandatory for most types of merchant ships on a rolling deadline from 2012. (SOLAS ch.V reg.19 pa.2.10. and SOLAS ch.V reg.19 pa.2.11.). Fig. 1- Compulsory carriage of ECDIS [from the future of navigation, 2012] 9 ECDIS 001/000 THE ECDIS-MINDSET Electronic charts and the systems they populate represent a new approach to navigation because, rather than providing a simple computer display or acting as a paper reference, an electronic chart is the core component in a navigation system that integrates a range of real-time information for display to the mariner. Nevertheless, while a huge technological and operational leap forward; electronic navigation is no substitute for sound judgement and situational awareness. ECDIS is only a tool to support the mariner performing navigational tasks. A navigational watch is never to be performed on only one system. TRAINING “… Shipowners and operators should ensure that their ships’ crews are provided with a comprehensive familiarization programme and type specific training…” (SN./Circ.276) 2.8.1 LEGAL ASPECTS STCW INCLUDING 2010 MANILA AMENDMENTS Training in ECDIS for STCW-certification has been addressed by the 2010 Manila Amendments to the STCW Convention and Code. STCW now includes specific mandatory requirements for certification of officers in charge of a navigational watch with regard to the use of ECDIS to maintain the safety of navigation. ISM CODE By the terms of the ISM code, the ship owner or operator must ensure that personnel are given proper familiarisation with their duties. The code states: “The Company should establish procedures to ensure that new personnel transferred to new assignments related to safety and protection of the environment are given proper familiarization with their duties” and “Instructions which are essential to be provided prior to sailing should be identified, documented and given. The Company should establish and maintain procedures for identifying any training which may be required in support of the safety management system and ensure that such training is provided for all personnel concerned”. In the case of ECDIS this means that, if a ship is equipped with an ECDIS as primary means of navigation at sea, the ship owner or operator has to provide ECDIS training to ensure that ECDIS users are both properly trained and familiar with the shipboard equipment before it is used. 2.8.2 TRAINING REQUIREMENTS The ship owner or operator should ensure that their ships’ crews are provided with both a generic training and a type-specific training.  generic training will be provided by a college or other training establishment and will be based on the IMO Model Course 1.27  type-specific training, or familiarization training, could be carried out in a number of ways: by means of CBT modules, shore-based training, ‘task force’-teams coming on board, … 2.8.3 FAMILIARIZATION CHECKLIST The Nautical Institute has produced a familiarisation list as useful way of checking the functionalities that should be understood and as guidance on how to access and use the equipment. A copy of this list can be found at their website: www.nautinst.org/en/forums/ecdis/. 10 001.000 ECDIS 3 OVERVIEW LEGAL ASPECTS AND REQUIREMENTS Three organisations are involved in ECDIS legislation:  The IMO: International Maritime Organisation www.imo.org  The IHO: International Hydrographic Office www.iho.int  The IEC: International Electrotechnical Commission www.iec.ch IMO: SOLAS CHART CARRIAGE REQUIREMENTS SOLAS Chapter V (Safety of Navigation) has a number of requirements regarding the use of (electronic) charts:  SOLAS ch.V reg.2 (definition nautical chart) “. For the purpose of this chapter: 2. Nautical chart or nautical publication is a special-purpose map or book, or a specially compiled database from which such a map or book is derived, that is issued officially by or on the authority of a Government, authorized Hydrographic Office or other relevant government institution and is designed to meet the requirements of marine navigation.”  SOLAS ch.V reg.19pa.2.1.4 (number of charts to be carried on board) “2.1. All ships irrespective of size shall have:.4. nautical charts and nautical publications to plan and display the ship’s route for the intended voyage and to plot and monitor positions throughout the voyage; an electronic chart display and information system (ECDIS) may be accepted as meeting the chart carriage requirements of this subparagraph;”  SOLAS ch.V reg.19 pa.2.1.5 (back-up arrangements) “2.1. All ships irrespective of size shall have:.5. back-up arrangements to meet the functional requirements of subparagraph.4, if this function is partly or fully fulfilled by electronic means; Footnote : An appropriate folio of paper nautical charts may be used as a back-up arrangement for ECDIS. Other back-up arrangements for ECDIS are acceptable (see appendix 6 to resolution A.817(19), as amended). “  SOLAS ch.V reg.20 (adequate and up to date publications and charts) “. Nautical charts and nautical publications, such as sailing directions, lists of lights, notices to mariners, tide tables and all other nautical publications necessary for the intended voyage, shall be adequate and up to date.” 11 ECDIS 001/000 IMO: SOLAS ECDIS CARRIAGE REQUIREMENTS  SOLAS ch.V reg.19 pa.2.10 (mandatory carriage of ECDIS) “Ships engaged on international voyages shall be fitted with an Electronic Chart Display and Information System (ECDIS) as follows:.1 passenger ships of 500 gross tonnage and upwards constructed on or after 1 July 2012;.2 tankers of 3,000 gross tonnage and upwards constructed on or after 1 July 2012;.3 cargo ships, other than tankers, of 10,000 gross tonnage and upwards constructed on or after 1 July 2013;.4 cargo ships, other than tankers, of 3,000 gross tonnage and upwards but less than 10,000 gross tonnage constructed on or after 1 July 2014; 5. passenger ships of 500 gross tonnage and upwards constructed before 1 July 2012, not later than the first survey* on or after 1 July 2014; 6. tankers of 3,000 gross tonnage and upwards constructed before 1 July 2012, not later than the first survey on or after 1 July 2015; 7. cargo ships, other than tankers, of 50,000 gross tonnage and upwards constructed before 1 July 2013, not later than the first survey on or after 1 July 2016; 8. cargo ships, other than tankers, of 20,000 gross tonnage and upwards but less than 50,000 gross tonnage constructed before 1 July 2013, not later than the first survey on or after 1 July 2017; and 9. cargo ships, other than tankers, of 10,000 gross tonnage and upwards but less than 20,000 gross tonnage constructed before 1 July 2013, not later than the first survey on or after 1 July 2018.”  SOLAS ch.V reg.19 pa.2.11 (exemption) “Administration may exempt ships from the application of the requirements of paragraph 2.10 when such ships will be taken permanently out of service within two years after the implementation date specified in subparagraphs 2.10.5 to 2.10.9 of paragraph 2.10.” IMO: PERFORMANCE STANDARDS FOR ECDIS The initial performance standards from 1995 were further improved, taking into account the technological progress and experience gained over time. IMO keeps in revision these performance standards.  1995, IMO Resolution A.817(19) - Performance Standards for electronic chart display and information systems This Resolution states that ‘the primary function of the ECDIS is to contribute to safe navigation’ and that the ’use of ECDIS should reduce the navigational workload as compared to use of paper charts’.  1996, IMO Resolution MSC.64(67) – Adoption of new and amended Performance Standards Annex 5 of this resolution details the back-up requirements.  1998, IMO Resolution MSC.86(70) - Adoption of new and amended Performance Standards for navigational equipment. Annex 4 of this resolution allows the RCDS mode of operation.  2004, IMO Resolution MSC.191(79) – Performance Standards for the Presentation of navigation- related information on shipborne navigational displays. 12 001.000 ECDIS  2006, IMO Resolution MSC.232(82) – Adoption of the Revised Performance Standards for Electronic Chart Display and Information Systems.  SOLAS ch.V reg.18 pa.4 (all newly installed equipment must comply with the latest performance standards for ECDIS) IMO: TRAINING REQUIREMENTS  2011,STCW Convention and STCW Code, including 2010 Manila Amendments This document provides the legal framework for training, certification and watch keeping and provides guidance to assist those involved in educating, training or assessing the competence of seafarers.  2012, IMO Model Course 1.27: the operational use of electronic chart display and information systems (ECDIS) The model courses provide a course framework, a course outline, a detailed teaching syllabus, guidance notes for the instructor, and a summary of how students should be evaluated. IMO, IHO, IEC: TECHNICAL STANDARDS AND SPECIFICATIONS The IMO, IHO and IEC have developed technical standards and specifications for use in conjunction with the Performance Standards. These publications are not aimed at use by the mariner. 3.5.1 IMO DOCUMENTS  1991, IMO Resolution A.694(17) – General Requirements for Shipborne Radio Equipment Forming Part of the Global Maritime Distress and Safety System (GMDSS) and for Electronic Navigational Aids  1999, IMO SN/Circ.207 – Differences between RCDS and ECDIS  2008, IMO SN/Circ. 276 – Transitioning from paper chart to ECDIS navigation  2000, IMO MSC/Circ.982 – Guidelines on Ergonomic Criteria for Bridge Equipment and Layout  2004, IMO Resolution MSC.191(79) – Performance Standards for the Presentation of Navigation- related information on Ship borne Navigational Displays  2004, IMO SN/Circ.982 – Guidelines on the Presentation of Navigation-related Symbols, Terms and Abbreviations 3.5.2 IHO DOCUMENTS  S-32: Hydrographic Dictionary  S-52: Specifications for Chart Content and Display Aspects of ECDIS Appendix 1: guidance on updating the electronic navigational chart Appendix 2: colour and symbols specifications for ECDIS Appendix 2(A): presentation library  S-57: IHO Transfer Standard for Digital Hydrographic Data Appendix A: object catalogue  S-61: IHO Product Specification for Raster Navigational Charts  S-63: IHO Data Protection Scheme 13 ECDIS 001/000 3.5.3 IEC DOCUMENTS  IEC Publication 60945 - Maritime navigation and radio communication equipment and systems - General requirements - Methods of testing and required test results  IEC Publication 61162 - Maritime navigation and radio communication equipment and systems - Digital interfaces - Part 1: Single talker and multiple listeners  IEC Publication 61174 - Maritime navigation and radio communication equipment and systems - Electronic chart display and information system (ECDIS) - Operational and performance requirements, methods of testing and required test results  IEC Publication 62288 - Maritime navigation and radio communication equipment and systems – Presentation of navigation-related information on ship borne navigational displays – General requirements, methods of testing and required test results Fig. 2 - Organizations involved in ECDIS legislation [LB, 2013] 14 001.000 ECDIS 4 ELECTRONIC CHART DATA RASTER DATA VERSUS VECTOR DATA 4.1.1 RASTER DATA An image in raster format is captured as picture elements or pixels. These pixels are automatically aligned in rows and columns. The pixels do not contain more information than the assigned colour and brightness value. They do not know anything about the information they represents, or their relationship to adjacent areas. Fig. 3 - Raster data setup 4.1.2 VECTOR DATA Vector data is object-oriented data. In order to produce object-oriented data, the sequence of cartographic events is turned around. First the information of the area to be captured is identified and classified: geometric and graphical elements of the chart are isolated (points, lines, areas and text) and then the information belonging to these elements is attached to them as attributes. Fig. 4 - Object and attributes 15 ECDIS 001/000 For example: a safe water buoy:  a buoy will be connected to one specific geographical location; it will be considered being a point  the type of buoy has to be defined: the feature object class. In our example: a safe water buoy  for each feature object S-57 defines a list of characteristics: attributes. Each object class identifies the actual attributes that are relevant for that specific object. In our example these include the buoy shape, colour, etc. Fig. 5 - Safe water buoy [from IHO S-57, 2000] The data from all the objects is stored in a database. Geographic reference is produced directly from the geographic coordinates. Once all information belonging to the object is attached, appropriate chart graphics are generated in a quasi-automatic way. The use of object-based data allows moving from a simple chart image to an interactive information system. Mechanics are built into the system to query the data, to adjust the display detail to your specific needs and to generate automatic alarms. PICK REPORT OR ‘CURSOR INTERREGATION’ On demand, the ECDIS will display the information about the chart objects for an operator identified geographical position, e.g. by cursor picking. Fig. 6 - Pick Report [from Transas Navi-sailor 4000] 16 001.000 ECDIS DISPLAY DETAIL When using vector data, the user has some control of the type of objects that are displayed. The different information categories in an electronic chart are often called layers, because they can be linked to transparent sheets, each printed with information of a single category. An ECDIS operator can select which layers to be visible on the monitor at a certain stage. Note that it is not possible to remove individual items, such as an individual sounding or a particular buoy; only categories can be removed or added. Fig. 7 - Removing / adding layers [LB, 2013] There are three main options for the setting of detail: Display Base, Standard Display and All other information. An operator may also customize the display to his own needs: Customized Display. 1 Display Base The IMO Display Base is that part of the displayed information which cannot be removed from the display. It is a list of basic objects which the IMO considers are required at all times, in all geographic areas and under all circumstances. Display Base is not intended to be sufficient for safe navigation. Fig. 8 - Display Base [from Transas Navis-sailor 4000] 17 ECDIS 001/000 2 Standard Display This default display is intended to be used as a minimum during route planning and route monitoring. IMO Performance Standards require that it is possible to access this Standard Display by a single operator action. Fig. 9 - Standard Display [from Transas Navi-sailor 4000] 3 All Other Information or All Layers This display contains all other information available in the system. Fig. 10 - All Layers [from Transas Navi-sailor 4000] 4 Customized Display An operator can now add or remove layers from the display: he can customize his display up to his specific needs at a certain moment. Fig. 11 - Customized Display [from Transas Navi-sailor 4000] The IMO Performance Standards for ECDIS include a table with layers that have to be included in the different display settings. When an ECDIS is switched on following a switch off or power failure, it should return to the most recent manually selected settings for display. 18 001.000 ECDIS Minimum Base Display Minimum Standard Display Extra on demand Coastline (high water) All information contained in the Spot soundings Display Base + Own ship’s safety contour (to be Submarine cables and pipelines selected by the operator) Drying line Ferry routes Indication of isolated underwater Indication of fixed and floating aids dangers at depths of less than the to navigation Details of all isolated dangers safety contour which lie within the Boundaries of fairways, channels, Details of aids to navigation safe waters defined by the safety contour ect Contents of cautionary notes Indication of isolated dangers Visual and radar conspicuous ENC edition date which lie within the safe water features defined by the safety contour such Geodetic datum Prohibited and restricted areas as bridges, overhead wires, ect., Magnetic variation including buoys and beacons, Chart scale boundaries whether or not these are being Graticule used as aids to navigation Indication of cautionary notes Place names Traffic routeing systems Scale, range, orientation and display mode Units of depth and height Fig. 12 - Minimum information for Standard display settings [from IMO Performance Standards, 2006] GENERATION OF AUTOMATIC ALARMS ECDIS provides automatic alerts when the route is planned without satisfactory clearance to grounding dangers and when the ship approaches areas or objects representing a danger to the ship. 19 ECDIS 001/000 OFFICIAL DATA VERSUS PRIVATE DATA Chart data can either be official or private. To be ‘official’ chart data must meet two requirements: 1 the data must be authorised by a national government agency, usually the national Hydrographic Office 2 the data must meet the specifications of the IHO Only official chart data can be used to fulfill the SOLAS carriage requirements (SOLAS Ch. V. reg. 2). The content of official charts is the responsibility and liability of the issuing Hydrographic Office. Official vector data is called ENC data; official raster data is called RNC data. All non-official data is called private data. Raster Data Vector Data Official Data RNC Data ENC Data Non-official Data Private Data Fig. 13 - RNC Data, ENC Data and Private Data An ECDIS is able to distinguish non-official data from. If non-ENC data is shown on the ECDIS display, the ENC’s boundary is identified by a one-sided orange line with the diagonal stroke on the unofficial side of the line. Fig. 14 - ENC data (left) and non-ENC data (right) [from Transas Navi-sailor 4000] 20 001.000 ECDIS 5 ELECTRONIC CHARTS ELECTRONIC NAVIGATIONAL CHARTS (ENCS) An ENC is defined in the IMO Performance Standards as follows: “Electronic Navigational Chart (ENC) means the database, standardised as to content, structure and format, issued for use with ECDIS by or on the authority of a Government, authorized Hydrographic Office or other relevant government institution, and conform to IHO standards. The ENC contains all the charts information necessary for safe navigation and may contain supplementary information in addition to that contained in the paper chart (e.g. sailing directions) which may be considered necessary for safe navigation.” IHO STANDARDS FOR ENCS 5.2.1 DATA FORMAT USED IHO S-57: TRANSFER STANDARD FOR DIGITAL HYDROGRAPHIC DATA The IHO has defined a uniform data exchange format in IHO S-57 ‘Transfer Standard for Digital Hydrographic Data’. Member states are requested to produce and distribute electronic charts in this format. Transfer and distribution have to take place in such a way that none of the meaning of the data is lost. Currently IHO is working on a new standard: S-101 ’Standard for future Electronic Navigational Charts’, based on the concepts described in S-100 ‘Universal Hydrographic Data Model’. S-100 provides the data framework for the development of the next generation of ENC products, as well as other related digital products required by the hydrographic, maritime and GIS communities. S-100 came into force on 1 January 2010 and extends the scope of the existing S-57 Hydrographic Transfer standard. SYSTEM ELECTRONIC NAVIGATIONAL CHART (SENC) SENC is defined in the IMO Performance Standards as follows: “System Electronic Navigational Chart (SENC) means a database, in the manufacturer’s internal ECDIS format, resulting from the lossless transformation of the entire ENC contents and its updates. It is this database that is accessed by ECDIS for the display generation and other navigational functions, and is equivalent to an up-to- date paper chart. The SENC may also contain information added by the mariner and information from other sources.” An ECDIS should be capable of displaying all SENC information. An ECDIS should be capable of accepting and converting an ENC and its updates into a SENC. The ECDIS may also be capable of accepting a SENC resulting from conversion of ENC to SENC ashore1. This method of ENC supply is known as SENC- delivery. 1 In accordance with IHO TR 3.114. 21 ECDIS 001/000 Fig. 15 - SENC-delivery 5.2.2 DISPLAY ASPECTS IHO S-52: SPECIFICATIONS FOR CHART CONTENT AND DISPLAY ASPECTS OF ECDIS The obligatory uniform way of presenting the electronic navigational chart data on the screen is specified in IHO S-52 Appendix 2 ‘Colour and Symbols Specifications for ECDIS’ and in its Appendix 2(A) ‘Presentation Library’. SYMBOL LIBRARY A set of symbol diagrams in the form of S-57 compliant charts are included for use as a Mariners ECDIS Chart 1. These charts explain the use and meaning of the symbols through cursor picking. Fig. 16 - Mariner ECDIS Chart 1 (from Transas Navi-sailor 4000) 22 001.000 ECDIS THE ‘QUESTION MARK SYMBOL & THE NEW OBJECT If insufficient information is available to fully display a feature, a default symbol accompanied by a question mark will be shown. This may occur if a significant characteristic s as the shape of an aid to navigation is not included in the ENC-data, e.g.: Fig. 17 –Question Mark Symbol (aa5c1ab2) The Pick Report or ‘cursor interrogation‘ will display all available information attributed to the object within the ENC, even if the object is marked by the question mark symbol. An ENC may contain a feature called New Object, which is used to represent features for which no specific object exists. The definition of the New Object can be found through the pick report. A New Object may include a symbol instruction which determines its display, if not included it will display as follows: Fig. 18 – New Object (aa5c1ab2) 23 ECDIS 001/000 SIMPLIFIED SYMBOLS FOR AIDS TO NAVIGATION ENC data for ‘aids to navigation’-symbols as buoys and beacons, can be shown using 2 symbol formats: 1 in a format based on traditional paper chart symbols or 2 as ‘simplified’ symbols which have been designed to be more distinguishable on an ECDIS display:  for lateral, cardinal, isolated danger and safe water buoys, sloping topmark symbols are used, coloured in the single most distinctive colour of the buoy  special mark buoys are yellow  all mooring buoys resemble the paper chart ‘installation buoy’  the default buoy, used when a buoy is not fully described in the ENC or has no specific symbol in the presentation library, is a filled grey circle Fig. 19 - Paper Chart Symbols – Simplified Symbols (from Transas Navi-sailor 4000) Note that all simplified point symbols are centered on the position of the feature. The details of buoy characteristics, which cause clutter and are difficult to show clearly on an electronic display under all bridge lighting conditions, are provided by text command or by individual cursor interrogation. When the name or number of a buoy or beacon is displayed, it will be prefixed ‘By’ or ‘Bn’, since otherwise a number can be mistaken for a sounding. LINE STYLES The presentation library uses 2 types of line styles: 1 the simple line style: solid dashed or dotted lines with varying colour and thickness 2 the complex line style: composed of repeating line patterns Fig. 20 - Simple Line Style – Complex Line Style (from Transas Navi-sailor 4000) 24 001.000 ECDIS AREA PATTERNS AND CENTRED SYMBOLS Sometimes only a part of an area may appear on the monitor of the ECDIS. Therefore, in addition to the symbols derived from the paper chart, ECDIS has an additional class of symbols: the area patterns. A fishing area or anchoring prohibited area will then be filled with a pattern of the corresponding symbol repeated at certain distances within the shown section of the relevant sea area. As an alternative centred symbols might be used: a symbol will not have a fixed position on the chart, instead the symbol will automatically move to the centre part of the area that remains in the display window. Fig. 21 - Centred Symbol (LB, 2012) IHO ENC / ECDIS DATA PRESENTATION AND PERFORMANCE CHECKS The IHO ENC/ ECDIS data presentation and performance checks are intended to make mariners aware of any shortcomings with their ECDIS and of the possibility that their ECDIS software might require updating. The required dataset existing out of two fictious ENCs (aa2tds02 and aa5tds05), some instructions and a feedback form can be downloaded from the IHO-website (www.iho.int). Fig. 22 - Initial display of the check ENC cells (from IHO ENC / ECDIS data presentation and performance checks) 25 ECDIS 001/000 CONDITIONAL SYMBOLIZATION Most objects can be presented in a straightforward manner. Some objects are only to be displayed over a certain period (for example buoys) or may have a date on which they are introduced or discontinued (for example traffic separation schemes). An object should normally not be displayed outside its effective dates. Date depended attributes as PERSTA, PEREND, DATSTA and DATEND will be added to that object. There is also an attribute which determines the display scale below which the object is no longer displayed: SCAMIN. Its purpose is to reduce clutter, to prioritize the display of objects and to improve display speed. For example: an object with a SCAMIN value of 20,000 (indicating a scale of 1/20,000) will no longer be visible on a scale of 1/30,000. Spot soundings and buoys are examples of items which do not need to be shown on overview scales, but will appear when zooming in. Fig. 23 - SCAMIN off (left) - SCAMIN on (right) (BE4VLBKN @ 1:150,000) UNITS There should be no ambiguity about the units in use at a particular time. The units listed below should be indicated in the display legend:  position: latitude and longitude in degrees, minutes and decimal minutes  depth: meters and decimeters  height: meters  distance: nautical miles and decimal miles, or meters  speed: knots and decimal knots REFERENCE SYSTEM USED ENCs are always referred to WGS84. 5.2.3 IHO S 63: DATA PROTECTION SCHEME IHO S-63 specifies a method of securing ENC information by encrypting the information and applying a digital signature to it. The purpose of data protection is threefold:  piracy protection: to prevent unauthorized use of data by encrypting the ENC information  selective access : to restrict access to ENC information to only those cells that a customer has been licensed for  authentication : to provide assurance that the ENC data has come from approved sources and it has maintained the integrity in all transactions between the service provider and the end-user An ECDIS should be capable of accepting both non-encrypted ENCs and ENCs encrypted in accordance with the IHO Data Protection Scheme. 26 001.000 ECDIS RASTER NAVIGATIONAL CHARTS (RNCS) RNC is specified in the IMO ECDIS Performance Standards as follows: “Raster Navigational Chart (RNC) means a facsimile of a paper chart originated by, or distributed on the authority of, a government-authorised Hydrographic Office.” IHO STANDARD FOR RNCS 5.4.1 DATA FORMAT AND DISPLAY ASPECTS IMO has from the beginning concentrated on developing vector charts, as the capabilities of these charts were far greater than those of raster charts. Therefore there is no standard defining the underlying raster data structure of a raster navigational chart: the national hydrographic office producing the RNC should select a data structure. There is no standard defining the display aspect of a RNC either: colors, symbols, units and reference systems used may differ depending on which national hydrographic office has produced the RNC. 5.4.2 IHO S-61: PRODUCT SPECIFICATIONS FOR RASTER NAVIGATIONAL CHARTS IHO S-61 does not define the detailed structure of RNC data as S-57 does for ENC data. Instead it puts certain minimum requirements on it, particularly concerning what meta data should be included. This is data separate from the image that can be accessed by the RCDS software of an ECDIS. For example: producing agency identifier, RNC number, chart edition date, last update or NtM applied, chart scale, depth and height units, orientation of north, horizontal datum, horizontal datum shift, vertical datum, etc. Much of the information in the meta-data is for automatic use by the software. Some may be displayed permanently or on demand of the user. 5.4.3 DATA STRUCTURE In the data structure, the chart image is normally held as a grid of small squares of data directly imaged from the original paper chart. When updates to the data are required, only the cells that changed need to be sent, together with the S-61 required meta-data. Fig. 24 - RNC (left) versus ENC (right) (from Transas Navi-sailor 4000) 5.4.4 USE OF RASTER NAVIGATIONAL CHARTS Current regulations do not support the use of RNCs for primary navigation when used independently of ENCs, and without some form of paper chart back-up. One has to use ENCs where available and may only use RNCs to fill the gaps. We call this a ‘dual-fuel’ combination. 27 ECDIS 001/000 PRIVATE DATA All other, non-official, charts are referred to as private charts. These charts are not accepted as the basis for navigation under the SOLAS convention. Nevertheless they can be very useful and many ships use private charts on an ECS to supplement the continued use of official paper charts. Most private data has been produced by scanning up-to-date paper charts issued by Hydrographic Offices. Nevertheless, Hydographic Offices do not take any responsibility for the accuracy or reliability of privately produced charts! There are no mandatory international regulations governing the production and supply of private data, so not all private suppliers may supply data of good quality and symbology used on private vector data will not necessarily follow that required for ENC data displayed on ECDIS. Fig. 25 - Overview Electronic Charts (LB, 2012) 28 001.000 ECDIS 6 ERRORS OF DISPLAYED DATA Electronic chart accuracy is, for the most part, dependent on the accuracy of the chart information. ENC and RNC data only have equivalent accuracy as the paper charts from which they are replicated and may contain errors in source data or compilation errors or may just not be suitable to be used for the purpose in hand. ERRORS IN SOURCE DATA The accuracy of a chart is only as good as the accuracy of the hydrographical data provided. Until about twenty years ago, position fixes were typically obtained using radar ranges, visual bearings or Loran C. These positioning methods were generally an order of magnitude less accurate than the horizontal accuracy of the survey information portrayed on the chart. Nowadays, positioning systems are more accurate, but electronic charts (RNC or ENC) are still based paper charts. Therefore the horizontal accuracy of electronic charts will not meet the accuracy of the positioning systems now available. The data may be inaccurate because:  the survey may be inaccurate: features may have been undetected  the datums may not be defined on old survey data  the survey methods used may be inaccurate: from sextant and lead-line to GPS and echo sounder  there may have been physical changes to the charted situation since the area was surveyed  sea-bottom topography may be continuously changing COMPILATION ERRORS Before scanning charts into raster format, chart compilation was performed manually, allowing following discrepancies and errors:  restricted print clarity of paper charts  low scanning resolution of paper charts  low screen resolution  human error CATEGORY OF ZONE OF CONFIDENCE IN DATA (CATZOC OR ZOC) On RCDS and paper charts the source data diagram within the notes should be consulted to establish survey dates. (Often other data to help the users to establish an appropriate degree of confidence is as also given.) For ENCs, IHO is encouraging Hydrographic Offices to include ‘zone of confidence’ data, indicating the reliability of the source data. The categorisation of hydrographic data is based on three factors:  position accuracy  depth accuracy  sea floor coverage The CATZOC-attribute is divided into 6 category levels: A1, A2, B, C, D and U. An overview of these categories can be found The Mariners Handbook. 29 ECDIS 001/000 Fig. 26 - CATZOC categories When using ENCs, users must always be aware of the reliability of the source data for the areas of navigation covered by the voyage. CATZOC-information is displayed on the ECDIS as a series of asterisks in an enclosed shape. An overview of these symbols can be found in the Mariners Handbook. Fig. 27 - Graphic display of CATZOC categories B, D and U (from left to right) 30 001.000 ECDIS 7 ECDIS OR ECS ECDIS AND THE PERFORMANCE STANDARDS As a ship borne navigational device, ECDIS is the responsibility of IMO and must support the whole range of navigational functions that make use of the characteristics of the electronic chart data and their specific presentation. These functions have been listed up in the IMO Performance Standards for ECDIS. To be an ECDIS, the equipment must be shown to meet all the requirements of the IMO Performance Standards. ECDIS TYPE APPROVAL ECDIS type approval is the certification process that ECDIS equipment must undergo before it will be considered to comply with the IMO Performance Standards for ECDIS. To prove this compliance, most Flag States require independent type approval by a recognized type-approval organization or classification society authorized by the flag state. The type approval is based on test procedures developed by the International Electrotechnical Commission (IEC), which are again based on IMO ECDIS Performance Standards that apply IHO requirements S-52 and S-57. After receiving type approval, a certificate of type approval will be issued. Whether the equipment meets IMO requirements should also be evident from a permanent label attached to the equipment: in Europe this will include the ‘wheel mark’ symbol. Fig. 28 - Wheelmark Symbol (from Labtestcertification inc. 2012) This symbol is applied to all EU approved bridge equipment2, and must be accompanied with the number of the IEC standard concerned. The prime standard for ECDIS equipment is IEC 61174; which mainly covers environmental test standards. ECDIS MODE OF OPERATION A type approved ECDIS may operate in 2 modes: 1 ECDIS mode when ENC data is used 2 RCDS mode when RNC data is used The IMO performance standards for ECDIS state that, where ENCs are not available, RNCs may be used in ECDIS to meet carriage requirements. The intention is to allow the ECDIS to operate as far as possible on official chart data: ENCs where they are available and RNCs to fill the gaps (‘dual fuel’). 2 Directive 96/98/EC on Marine Equipment. 31 ECDIS 001/000 7.3.1 ECDIS IN ECDIS MODE Only an ECDIS in ECDIS mode, which means an ECDIS using up-to-date ENCs, might meet the IMO regulations for paperless navigation. Users should consult their Flag State as whether it allows paperless navigation or not, and under which conditions. For example: Belgium allows paperless navigation; France does not allow paperless navigation for the ships flying its flag. 7.3.2 ECDIS IN RCDS MODE RCDS AND THE PERFORMANCE STANDARDS RCDS is defined in the Performance Standards as follows: “Raster Chart Display System (RCDS) means a navigation information system displaying RNCs with positional information from navigation sensors to assist the mariner in route planning and route monitoring, and if required, display additional navigation-related information." The RCDS mode of operation is contained in Appendix 7 of the IMO Performance Standards. APPROPRIATE PORTFOLIO OF UP-TO-DATE PAPER CHARTS (APC) When the ECDIS is running in RCDS mode, it does not have the full functionality of ECDIS. Users should consult their Flag State as to whether RCDS mode is allowed and under what conditions. Generally, it is considered necessary to have an appropriate paper chart available on the chart table to improve look-ahead knowledge. The folio of these charts needed for a particular voyage is known as the Appropriate Portfolio of up-to-date paper charts or APC, and is defined by IMO as follows: “A suite of paper charts of a scale to show sufficient detail of topography, depths, navigational hazards, aids to navigation, charted routes, and routeing measures to provide the mariner with information on the overall navigational environment.” Depending on the Flag State, these charts may not need to show much or any chart work. The IHO maintains a list of charts that coastal states see as appropriate when using the ECDIS in RCDS mode, available on www.iho-ohi.net/english/encs-ecdis/enc-availability/backup-paper-charts.html. Following guidance is given concerning the scale of the chart appropriate for a particular stage of the voyage: General route appraisal or oceanic passage medium-scale charts in the range execution: 1:175,000 to 1:1500,000 General route appraisal or passage execution in medium-scale charts in the range open seas: 1:100,000 to 1:1500,000 General route appraisal or passage execution in charts with a scale congested coastal waters or port approaches: larger than 1:100,000 Fig. 29 - Guidance on appropriate chart scale for particular stage of the voyage (from www.iho-ohi.net 17/08/2012) 32 001.000 ECDIS DIFFERENCES BETWEEN RCDS AND ECDIS In order to draw the mariner’s attention to the limitations of the RCDS mode of operation, the Maritime Safety Committee has issued a circular: SN.1/Circ.207/Rev.1 ‘Differences between RCDS and ECDIS. ECDIS RCDS No displayed chart boundaries. Paper chart-based system with chart boundaries. No automatic alarms, unless from user-inserted Automatic alarms as for example anti-grounding. information. Horizontal datums and chart projections may differ Always referred to WGS84. between RNCs, which may lead to a shift in position. Chart features can be simplified. Chart features cannot be simplified. Without selecting different scale charts, the look- Good look-ahead capability. ahead capability may be somewhat limited. Orientation other than chart-up, may affect the Different orientation modes possible. readability of chart text and symbols. RNC features may not be interrogated to gain ENC features may be interrogated. additional information. Safety depth and safety contour are highlighted on Only possible when manually entered during route the display. planning. Different colours may be used to show similar chart Display according to S-52. information. An RNC should be displayed at the scale of the paper Virtually any scale can be selected. chart as excessive zooming in or zooming out can seriously degrade RCDS capability. ECDIS provides an indication in the ENC which allows No indication on RNCs for the quality of the a determination of the quality of the hydrographic hydrographic data, except for the source diagram or data: CATZOC. the zone of confidence diagram if available. Fig. 30 - Differences between RCDS and ECDIS (from SN.1/Circ.207/Rev.1) 7.3.3 ECDIS AS PRIMARY MEANS OF NAVIGATION OR AS TOOL FOR ENHANCED SITUATIONAL AWARENESS If an ECDIS is used as primary means of navigation, the ship should be able to reduce its reliance on paper charts, while when used as an tool for enhanced situational awareness, it will keep the paper and draw added value from ECDIS. Both must still comply with the Performance Standards. Official ENC data must still be used even when ECDIS is not employed as the primary means of navigation. 33 ECDIS 001/000 ECS MODE OF OPERATION All non-ECDIS electronic chart systems are classified as Electronic Charting Systems (ECS). An ECS may be able to use ENCs, RNCs or private data, and may function similar to an ECDIS, but can only be used as an aid to navigation. ECSs cannot be used to meet the SOLAS requirements. Therefore there are no IMO Performance Standards for ECS either. Where the vessel operates with ECS, the paper chart remains the official basis for navigation. The vessel must retain and use a full folio of up to date paper charts onboard, regardless of the type of electronic charts used. When non-official charts are being used on a type approved ECDIS, or RNCs are used in an area where adequate ENC are available, that ECDIS will also operate as an ECS as it is no longer meeting the SOLAS requirements. ELECTRONIC CHARTING SYSTEM AWARENESS When using electronic charts it is important to be aware of the status of the equipment. On board an ECS is often, incorrectly, called an ECDIS. The user however must know whether the equipment is an ECDIS or an ECS, as only ECDIS with appropriate back-up can be used to replace paper charts. It also has to be understood that an ECDIS with non-official data, is considered by IMO to be an ECS and thus paper charts need to be used as primary means of navigation. Fig. 31 - ECDIS / ECS modes of operation - overview 34 001.000 ECDIS 8 BACK-UP SYSTEM IMO BACK-UP REQUIREMENTS No electronic equipment is completely failsafe. Therefore the IMO Performance Standards (Appendix 6) require the provision of adequate, independent, back up arrangements to ensure safe navigation in case of ECDIS failure. These arrangements have to include: 1 facilities enabling a safe take-over of the ECDIS functions in order to ensure that an ECDIS failure does not result in a critical situation 2 a means to provide for safe navigation for the remaining part of the voyage in case of ECDIS failure What is considered to be an appropriate back-up is a matter to be decided by the Flag State. An ECDIS configuration must at least meet IMO’s requirements for back-up as lined out in the Performance Standards, but more stringent requirements may be set by the Flag State. Commonly two back-up arrangements are accepted: 1 a second ECDIS, connected to an independent power supply and a continuous position-fixing system 2 an appropriate and up to date folio of official paper charts for the intended voyage DUAL ECDIS SOLUTION When using a dual ECDIS system:  both units should be switched on in normal circumstances  both units need to be loaded with the planned route and the alternative route data  all charts need to be up-to-date on both systems  the second unit should be in route-monitoring mode with the own ship displayed on the largest scale chart available and the appropriate route should be selected When using a dual ECDIS system, transferring is just a matter of moving from the first to the second equipment. PAPER CHART BACK-UP SOLUTION When using the paper chart back-up option:  an appropriate chart for the ship’s position must be available on the chart table  all charts must be corrected with the latest Notices to Mariners  a position must be plotted on the chart at suitable intervals  primary and alternative routes must be pre-plotted on the charts The IHO maintains a list of charts that coastal states see as appropriate when using the paper chart back-up option, available on www.iho-ohi.net/english/encs-ecdis/enc-availability/backup-paper-charts.html. Many of the benefits of ECDIS are eroded when paper charts are used for back-up: the workload in maintaining a paper chart back-up is almost the same as on a ship using paper charts as primary charting facility, in addition to the extra workload required for ECDIS, and both paper charts and ENCs and their updates have to be purchased. 35 ECDIS 001/000 OTHER BACK-UP SOLUTIONS A number of other possible options have been proposed that could meet the functional requirements. These include radar/arpa with ECS data superimposed a GPS/DGPS or GLONASS receiver with route planning functions, a print-on-demand system, an ECS, etc. These may only be used on condition of approval by the Flag State. A Flag State issued Certificate of Compliance should be held to indicate to Port State Inspectors that the back-up solution meets the requirements of the Flag State. FAULT DETECTION ECDIS is provided with means for either automatically or manually carrying out on-board tests of major functions. In case of a failure, the test should display information to indicate which module is at fault: the ECDIS will provide a suitable alarm or indication of system malfunction. The equipment, however, is unlikely to be able to detect all faults that could give rise to the display of incorrect navigational information, emphasising the need for continued vigilance on behalf of the OOW. TROUBLESHOOTING Many faults can often be cleared by simply restarting the ECDIS. For example: blank or corrupted displays, ultra-slow response to commands, inability to remove system error messages, etc. If a fault is due to interconnected equipment, one should switch to a secondary source if possible. If there is a perceived problem with the primary ECDIS, it is best to work with the back-up facility. 36 001.000 ECDIS 9 INTERFACING AND INTEGRATION CONNECTIONS WITH MANDATORY SENSORS The Performance Standards for ECDIS state that an ECDIS should be connected to following sensors:  the ship’s position fixing system  a heading device  the speed and distance measuring device 9.1.1 POSITION FIXING SYSTEM Electronic charts have the important advantage that they show continuously and automatically the actual position of the ship in real time (where positions plotted on a paper chart only show the position where the ship was some time before). Therefore a high quality position fixing system is the most important sensor. It is primarily GPS and DGPS that are the most commonly used. POSITION ACCURACY The ship’s position should be derived from a continuous positioning system of accuracy consistent with the requirements of safe navigation. Whenever possible, a second independent positioning source (preferably from a different type) should be provided. In such cases ECDIS should be capable of identifying discrepancies between the two sources. GPS IEC 61108-1 ± 100m GLONASS IEC 61108-2 ± 45m DGPS IEC 61108-1 ed.2 ± 10m Loran C IEC 61075 ed.1.0 ± 463m Fig. 32 - Position accuracy (with 95% confidence level) HORIZONTAL DATUM The positioning system and the SENC should be on the same geodetic datum. The ECDIS should give an alarm if this is not the case, as the position of the vessel on the electronic chart display can be seriously incorrect and misleading. WGS-84 is the specified datum for both GPS and the ENC data used in ECDIS. Different datums are sometimes used on raster charts, which have to be adjusted to WGS-84. 37 ECDIS 001/000 RISKS AND EFFECTS OF INACCURATE POSITION DETERMINATION Failure and reduced reliability of GPS and DGPS could occur through:  loss of view of individual GPS satellites caused by ship’s superstructure, multiple signal reflections, radio interference from other shipboard systems  loss of differential broadcast corrections due to weather fronts, lightning bursts or other meteorological disturbances  malfunctioning of the equipment  malicious jamming or GPS spoofing A defective or inaccurate position fixing system may lead to a false position display of the own ship on the ECDIS. With automatic position fixing and display, it is tempting to take the displayed positions for granted. Comparison with other means of position fixing and use of radar-overlay can be used to detect positional errors. MANUALLY FIXPOSITION ECDIS should provide the capability to enter and plot manually obtained bearing and distance lines of position (LOPs), and calculate the resulting position of the own ship. It should also be possible to use the resulting position as an origin for dead-reckoning. 9.1.2 HEADING AND SPEED MEASURING DEVICES Gyro compass and Doppler log offer the highest accuracy in practical onboard operations, plus they are independent of external signals. For ships not fitted with a gyro compass, the ECDIS should be connected to a marine transmitting heading device. Doppler logs are not required, but are installed on most modern ships. ACCURACY  the accuracy of a gyro is normally between 0.5° and 1°, and can increase to 3° or 4°during and after a manoeuvre due to an acceleration error  the accuracy of the speed over the ground (bottom track) measured is 0.2 to 1 kts, the accuracy of measured speed through the water (water track) will be lower due to effects of turbulence created by the ship  other compasses and logs used in navigation are less accurate 9.1.3 LOSS OF MANDATORY SENSORS The Performance Standards require an alarm to be given if the input from position, heading or speed sources is lost and also to repeat any alarm or indication passed to it from position, heading or speed sources as an indication. 38 001.000 ECDIS CONNECTIONS WITH OTHER NAVIGATIONAL EQUIPMENT The ECDIS Performance Standards state that the ECDIS display may also be used for the display of radar information and/ or AIS information from systems compliant with the relevant IMO Performance Standards. Other navigational information may also be added to the ECDIS display on condition:  it does not degrade the displayed SENC information  it should be clearly distinguishable from the SENC information  it should use the same reference system as the ECDIS, or provide an indication if this is not the case  it should be possible to remove all added information by a single operator action 9.2.1 RADAR / ARPA The transferred radar information may contain a radar image and/or tracked target information. RADAR IMAGE OVERLAY (RIO) Radar will proof to be a valuable position fixing tool, as the overlay provides a permanent radar-fix. The radar image and the position from the position sensor should both be adjusted automatically for antenna offset from the conning position. If the radar echo of fixed objects doesn’t match the corresponding ENC object, but is shifted over some distance, there must be an error in the EPFS (potentially in the geodetic datum). If the radar image is added to the ECDIS display, the chart and the radar image should match in scale and orientation. Nevertheless, RIO has some limitations:  true north versus gyro north: radar picture and ENC picture will be rotated against each other  sea stabilization versus ground stabilization  scale versus range To facilitate the display of the radar overlay on ENCs, Hydrographic Offices have been encouraged to set the compilation scales of their ENCs to be consistent with the standard radar range scales as shown in the following table: selectable range standard scale (rounded) 200 NM 1 : 3 000 000 96 NM 1 : 1 500 000 48 NM 1 : 700 000 24 NM 1 : 350 000 12 NM 1 : 180 000 6 NM 1 : 90 000 3 NM 1 : 45 000 1.5 NM 1 : 22 000 0.75 NM 1 : 12 000 0.5 NM 1 : 8 000 0.25 NM 1 : 4 000 Fig. 33 - radar range / standard scale (From facts about electronic charts, section 4, 22/06/2012  integration of information versus overload; therefore there must be a radar-off-switch to facilitate its removal  priority of chart data on the ECDIS: the radar data will only be shown in priority layer n° 7 39 ECDIS 001/000 Fig. 34 - The 10 Priority Layers: information content of category ‘n+1’ must not obscure the information content of category ‘n’ or any higher category (LB, 2012) ENC INFORMATION ON THE RADAR IMO Performance Standards for radar allow inclusion of selected layers of ENC information on the radar display. In this case the ECDIS chart data may not be obscuring the radar information. ARPA TARGET OVERLAY The big risk when using an ARPA target overlay is that only part of the traffic is displayed: targets not acquired on the radar screen will not show on the ECDIS. 9.2.2 AIS AIS data is third party data and can be misleading. AIS data should not be used to replace ARPA targets. 9.2.3 MARINE INFORMATION OBJECTS (MIOS) Marine Information Objects or MIOs consist of non-mandatory navigational information to be used with an ECDIS that is in addition to the information required for an ENC. MIOs may either be chart- related or operational-related. Following MIOs were agreed to be further investigated:  aids to navigation  ice systems  tides and water levels  current flow  tropical cyclones  oceanographic information  meteorological information  marine mammals  environmental protection  security  vessel traffic systems  search and rescue  imagery 40 001.000 ECDIS 9.2.4 AUTOMATIC TRACK CONTROL If a track-keeping autopilot has been fitted it is likely that the planned ECDIS route data can automatically be used to control it. When in automatic track-keeping mode great care must be taken to ensure that positional integrity is being checked at regular intervals: the autopilot and the ECDIS will be relying on the same positional data and so the display of the ship’s position will inevitably appear overlaying the planned track on the ECDIS display, even if there is a gross positional error! 9.2.5 VOYAGE DATA RECORDER In addition of some information being sent to the VDR, ECDIS has its own inbuilt voyage data recording facility which stores minimum the complete track for the entire voyage, with time marks at intervals not exceeding 4 hours. Also from the previous 12h it will record, with a one minute interval, information of the own ship’s past track (time, position, heading, speed) and information about the data used (ENC source, edition, date, cell and update history). This information, off course, cannot be manipulated or changed. From a legal perspective, the voyage record may be used as evidence for an investigation or in a court of law. Fig. 35 - Interfacing and integration (LB, 2012) 10 ECDIS POWER SUPPLY It should be possible to operate ECDIS and all equipment necessary for its normal functioning when supplied by an emergency source of electrical power in accordance with the appropriate requirements of chapter II-1 of the SOLAS Convention, as amended. Changing from one source of power supply to another or any interruption of the supply for a period of up to 45 seconds should not require the equipment to be manually re-initialized. 41 ECDIS 001/000 11 INTEGRITY OF THE NAVIGATIONAL SOLUTION The ECDIS Performance Standards state that the ECDIS should provide appropriate alarms or indications with respect to the information displayed or malfunction of the equipment. In the Performance Standards the definitions of alarms and indicators as provided in the IMO resolution A.830(19) ‘Code on Alarms and Indicators’ apply:  an alarm will announce a condition requiring attention by audible, or by audible and visual means  an indicator will give only a visual indication about the condition of a system or equipment ALARMS AND INDICATORS IN ECDIS MODE OF OPERATION The Performance Standards require following alarms and indications: alarm if the own ship will cross the safety contour (within specified time set by mariner) alarm or if the own ship will cross the boundary of a prohibited area or of a geographical area for indication which special conditions exist (within specified time set by the mariner) alarm if the specified cross track limit for deviation from the planned route is exceeded alarm if the input from position, heading or speed sources is lost if the own ship reaches a specified time or distance, set by the mariner, in advance of a alarm critical point on the planned route alarm if the positioning system and the SENC are not on the same geodetic datum alarm or in case of system malfunction indication if the default safety contour has been selected or when the safety contour in use indication becomes unavailable due to a change in source data indication if the information is diplayed at a larger scale than that contained in the ENC if the own ship’s position is covered by an ENC at a larger scale than that provided by the indication display indication if the ECDIS and the added information are not using a common reference system 42 001.000 ECDIS if the area covered by the ECDIS display includes waters for which no ENC at a scale indication appropriate for navigation is available, the areas representing those waters should carry an indication to the mariner to refer to the paper chart or to the RCDS mode of operation if information categories included in the standard display are removed to customize the indication display indication if the mariner plans a route across an own ship’s safety contour If the mariner plans a route closer than a user-specified distance from the boundary of a indication prohibited area or a geagraphic area for which special condition exist if the mariner plans a route closer than a user-specified distance from a point object, such indication as a fixed or floating aid to navigation or isolated danger if continuing on the present course and speed, over a specified time or distance set by the mariner, the own ship will pass closer than a user-specified distance from a danger indication (e.g. obstruction, wreck, rock) that is shallower than the mariner’s safety contour or an aid to navigation if the automatic or manual on-board test of major functions finds a module which is at indication fault Fig. 36 - Alarms and indicators in ECDIS mode of operation 11.1.1 SAFETY CONTOUR The ECDIS will allow you to select one of the depth contours available in the SENC and will clearly emphasize it over other contours on the display, e.g. by using a bold or black line. When selecting a safety contour one should give an adequate safety allowance for the actual draught of the vessel. Ideally, the safety contour will coincide with the depth contours available on the ENC cell in use. If there is no contour in the ENC cell that corresponds to the user-entered safety contour value, then the next deepest contour will be automatically selected by the ECDIS. If no safety contour has been set by the user, the default value of 30m will automatically be used. Fig. 37 - Safety contour (from us1eez1m) 43 ECDIS 001/000 DEEP AND SHALLOW WATER AREA INDICATION The ECDIS might allow you to choose between a 2-shades colour scheme and a 4-shades colour scheme (optional):  when using the 2-shades colour scheme, there will be a distinctive change in colour between areas shallower and areas deeper than the selected safety contour, e.g. blue for areas shallower than the safety contour and white for areas deeper than the safety contour. There is also an optional ‘depth less than safety contour’-pattern provided in the Presentation Library to reinforce the depth shade (especially at night).  when using the 4-shades colour scheme, the operator might add two more shades: 1 the first shade will fill the area between the drying line and the shallow contour 2 the second shade will fill the area deeper than the shallow contour but less deep than the safety contour 3 the third shade will fill the area deeper than the safety contour but less deep then the deep contour 4 the fourth shade will fill the remaining part of the chart which is deeper than the deep contour Fig. 38 - 2-shades vs 4-shades with shallow pattern (from us4pr60m) ISOLATED UNDERWATER DANGERS Isolated dangers (small shoals, rocks, wrecks, obstructions) of depth less than the safety contour, but lying within the safe water defined by the safety contour will be highlighted by the isolated danger mark. Fig. 39 - Isolated danger mark (from Transas Navi-sailor 4000) Because you may sometimes have to navigate in water shallower than a safety contour, the ECDIS allows you to select to also show isolated dangers in the 'unsafe' water between the displayed safety contour and the zero meter contour. 44 001.000 ECDIS SAFETY DEPTH The own-ship safety depth is intended as an aid when no appropriate safety contour is available in the SENC. ECDIS will emphasize soundings equal or less than the selected safety depth (whenever spot soundings are selected on the display). Fig. 40 - Safety depth (from us4pr60m) 11.1.2 SAFETY FRAME OR SAFETY DOMAIN In route monitoring mode, an ECDIS can check whether the own ship will be encountering charted features hazardous to navigation within a specific time set by the mariner. Imagine a volume around the ship that will give an alert when it encounters a hazard. This volume is defined by following parameters:  depth by safety contour and safety depth  (some systems will also allow a height input)  forward extent by look-ahead time or look-ahead range  lateral closeness by a user-specified distance Fig. 41 - Safety Domain / Safety Frame All alerts will be generated from the relevant chart at the largest available scale, whatever chart is being displayed on the ECDIS. It is important that above parameters are set to meet the particular circumstances: if set to high it will create numerous alerts, if set to low it will not provide timely warnings of potential hazards. Therefore the Safety Frame or Safety Domain will have to be adjusted during the voyage. 45 ECDIS 001/000 11.1.3 AREAS FOR WHICH SPECIAL CONDITIONS EXIST The following are the areas which ECDIS should detect and provide an alarm or indication in accordance with the Performance Standards:  traffic separation zones  inshore traffic zones  restricted areas  caution area  offshore production area  areas to be avoided  user defined areas to be avoided  military practice areas  seaplane landing areas  submarine transit lanes  anchorage areas  marine farms/ aquacultures  PSSAs 11.1.4 INFORMATION UNDER-SCALE AND INFORMATION OVER-SCALE IMO requires the effective size of the chart presentation on the display to be at least 270 x 270 mm, a very small area compared to a traditional paper chart. Zooming in and out is essential to maintain a good awareness of surrounding charted hazards. In order to stay aware of the scale of the displayed chart, you will always find a vertically drawn scale bar at the left of the chart display area, just clear of the border of the display. Zooming in to a scale that is larger than the compilation scale can be very dangerous, as charts intended to be used at a small scale contain a lot less detail than large scale charts. Therefore ECDIS will indicate that the over- scale with a specific indication on the display. Fig. 42 -(over-)scale indication (from Transas Navi-sailor 4000) When the display area covers more than one cell, it is possible that some ENC data is shown over-scale or under-scale. The ar