Introduction to the US Coast Guard differential GPS program

Background information is given explaining the need to broadcast differential Global Positioning System (DGPS) corrections to mariners. Results from a DGPS experiment carried out by the US Coast Guard (USCG) over the last three years are then discussed. In this experiment, differential corrections were modulated onto the signal from an existing maritime radiobeacon. The experiment proved that DGPS could provide the additional accuracy required for harbor and harbor approach navigation. As a result of this experiment the USCG is implementing a program to provide DGPS coverage to US harbors and harbor approaches. The authors discuss how this program will be implemented and the improvements to GPS accuracy and integrity that it will provide to mariners