The Global Positioning System, the first worldwide twenty-four hour, all-weather navigation system, is at last available to yachtsmen at an affordable price. This book aims to help owners get the best fram their sets and make full use of the faciliti es available, whether simply position fixing and course setting or interfacing with radar, loran, autopilots, logs, chart plotters, video sounders and fish finders. Conrad Dixon explains how to use and interpret the data received, test it for accuracy, and correct it when necessary. He advises what to look for when buying a set. how to achieve optimum accuracy and unravels the jargon associated with instruction manuals.