Satnav on the horizon

摘要

SATNAVS are something that most of us use without a second thought. But what happens at sea? Like drivers, maritime navigators can choose from a range of options, including GPS, paper maps, radar and ordinary radio communications. They can also use the Electronic Chart Display and Information System (ECDIS) - a kind of Google Maps for ships, It integrates GPS, radar and the Automatic Identification System (AIS) - which broadcasts to ships via radio signals - and displays a vessel's position on an electronic map in real time, along with precise readings of the local water depth.