Navigating close to shore

The author describes a new marine chart display information system that pinpoints a ship's position to within 3 meters and could have as great an impact as radar. The system uses an oceanographic chart on a video screen presented by an electronic data display information system (Ecdis) which looks much like a paper chart prepared by the hydrographic office. For its accuracy in fixing a ship's position, Ecdis depends on a navigation system, the differential Global Positioning System (DGPS). DGPS is now being installed along the US coastline by the Coast Guard, and will include some 50 on-shore stations that should be in place by January 1996. Other nations, including Australia, Canada, Finland, Norway, Sweden, and the United Kingdom, are also building such stations.<
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