Using GPS aims to help owners get the best from their sets and make full use of the facilities available, whether simply position fixing and course setting or interfacing with integrated navigation systems. In this second edition Conrad Dixon takes account of new developments in the electronics industry and explains how to use and interpret the data received, test it for accuracy and troubleshoot when necessary. He advises what to look for when buying a GPS set, how to achieve optimum accuracy, how to cope with signal interference, and explains how sulky hand-helds and 'starved' receivers can be coaxed back to life. Loran-C back-up to GPS is explained, as is DPGPS - the ultra-accurate derivative. Using GPS will help users understand what their sets are capable of, and will take them painlessly to a rich spread of data available at the press of a button. Seven sets are compared function by function.