ELECTRONIC CHART SYSTEM

Launched by the UK's Hydrographic Office, the Admiralty Raster Chart Service (ARCS) consists of digital (raster) chart images of Conventional Admiralty charts, stored on compact disk (CD-ROM) media.

These are Supplemented by the issue of a weekly Update disk (also CD-ROM) containing all Notices to Mariners information. This allows for the unique facility of automatic, error-free, correction of Admiralty raster charts. By providing official and fully correctable digital versions of Admiralty charts, the UK Hydrographic Office's initiative will significantly widen the development and the acceptance of Electronic Chart System (ECS) as an important aid to navigation.

IMO adopted minimum performance standards for ECDIS in 1995. The UK Hydrographic Office is making the product standard (Hydrographic Chart Raster Formart) for ARCS non — proprietary.

Chart Display Unit (CDU) offers interactive route planning and monitoring along with instantaneous assessment of tracked targets that may be overlaid on the chart from the radar system.

Chart Master unit comprises a high resolution 20-inch colour screen and dedicated control panel and has National Marine Electronic Association standard interfaces to provide full compatibility with other equipment such as ARPA Automatic Radar Plotting Aid radar and GPS receiversMost modern marine electronics can communicate with other pieces of electronics using a standardized electronic language or protocol, such as NMEA 0183. This is how GPS sends information to a chart plotter.

So important is the position-fixer input that all modern chart plotters can show GPS information such as latitude, longitude course and speed over the ground, and the time.

At present chart plotters are not a replacement for paper charts. There are obvious problems that affect electronics such as their aversion to the marine environment and power failure. An electronic chart does not provide as much accurate or up to date information as a new paper chart. This is particularly true of the dedicated chart plotters where screens are small and the chart makers have had to compromise over the amount of detailed information they can show. It is important for the users to appreciate the limitations of the plotter. The chart plotter should be viewed as an additional tool for navigators to take advantage of their benefits: continuous position updates automatically superimposed on a chart (perfect for a shorthanded, tired crew in bad weather): continuous track plotting; passage planning; automatic and detailed log entries; ease of calculating various options with a reduced risk of calculation errors, etc.

In this way paper charts remain an essential part of the navigational equipment, but play a different role. E.g. For example positions should be regularly plotted on the paper chart as a back up and a mental check, while the plotter log can run alongside the conventional log books. In restricted or unfamiliar waters, the navigator should revert to the paper chart.

II.NOTES:

acceptance - принятие, прием

interactive route planning - согласованное планирование пути

instantaneous assessment - мгновенная оценка

be overlaid - быть перекрытым

full compatibility - полная совместимость

NMEA 0183 National Marine - стандарт сопряжение Национальной Морской

Electronics Association 0183 Ассоциации Электроники

aversion - отвращение, антипатия

power failure - отказ в подаче электричества

update - обновление

superimposed - наложенный, нанесенный, добавленный unfamiliar - незнакомый

restricted - ограниченный

detailed - подробный

log entries - записи в журнале

III. ANSWER THE FOLLOWING QUESTIONS:

1. Who provides fully correctable digital versions of Admiralty raster charts?

2. What did IMO adopt?

3. What does chart master unit comprise?

4. Does on electronic chart provide accurate information?

5. What advantages does electronic chart system give?

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