Marine radars are X band or S band radars on ships, used to detect other ships and land obstacles, to provide bearing and distance for collision avoidance and navigation at sea. They are electronic navigation instruments that use a rotating antenna to sweep a narrow beam of microwaves around the water surface surrounding the ship to the horizon, detecting targets by microwaves reflected from them, generating a picture of the ship's surroundings on a display screen.
Radar is a vital navigation component for safety at sea and near the shore. Captains need to be able to maneuver their ships within feet in the worst of conditions and to be able to navigate "blind", when there is no visibility at night or due to bad weather. In addition to vessel-based marine radars, in port or in harbour, shore-based vessel traffic service radar systems are used by harbormasters and coast guard to monitor and regulate ship movements in busy waters.
Radars are rarely used alone in a marine setting. A modern trend is the integration of radar with other navigation displays on a single screen, as it becomes quite distracting to look at several different screens. Therefore, displays can often overlay an electronic GPS navigation chart of ship position, and a sonar display, on the radar display. This provides a combined view of surroundings, to maneuver the ship.
ECDIS formally stands for Electronic Chart Display and Information System, offering digital charts and navigational information so that seafarers can plan their routes much better and monitor where they are going. Essentially, it is a computer-based navigation system, using electronic charts and a variety of sensors, radar and fathometers to offer a safer alternative to paper maps.
The primary function of the ECDIS is to contribute to safe navigation.
ECDIS with adequate back-up arrangements may be accepted as complying with the up-to-date charts required by
regulation V/20 of the 1974 SOLAS Convention.
1n addition to the general requirements for shipborne radio equipment forming part of the global maritime distress
and safety system (GMDSS) and for electronic navigational aids contained in IMO resolution A.694 (17) 1,
ECDIS should meet the requirements of this performance standard.
ECDIS should be capable of displaying all chart information necessary for safe and efficient navigation
originated by, and distributed on the authority of, government authorized hydrographic offices.
ECDIS should facilitate simple and reliable updating of the electronic navigational chart
ECDIS should reduce the navigational workload compared to using the paper chart. It should enable the mariner
to execute in a convenient and timely manner all route planning, route monitoring and positioning currently
performed on paper charts. It should be capable of continuously plotting the ship's position.
ECDIS should have at least the same reliability and availability of presentation as the paper chart published by
government authorized hydrographic offices.
ECDIS should provide appropriate alarms or indications with respect to the information displayed or malfunction
of the equipment .
When the relevant chart information is not available in the appropriate form some ECDIS
equipment may operate in the Raster Chart Display System (RCDS) mode as defined in Appendix 7. Unless
otherwise specified in Appendix 7, the RCDS mode of operation should conform to performance standards not
inferior to those set out in this Annex
