Coast Guard to expand enhanced GPS system

The Coast Guard last week announced plans to double the coverage provided by its enhanced Global Positioning Satellite system that serves marine users navigating coastal and inland waterways.

The Coast Guard's National Differential GPS system uses a network of 54 land-based stations to provide positioning information accurate to within 10 meters or better, compared with 100 meters or better for the standard GPS signal provided to civilian users. But DGPS stations cover only a limited range, requiring more stations to cover more territory.

By 2002, the Coast Guard plans to turn on an additional 67 stations to blanket the country—including Alaska—said Capt. Joe Doherty, commander of the Coast Guard Navigation Center.

John Macaluso, who is managing expansion of the National DGPS effort at the Transportation Department's radio navigation and positioning policy branch, said the new network will provide highly accurate signals to a wide variety of non-marine users, including the nation's railroads.

Macaluso said the system will cost only $37 million to field, with savings built in by incorporating a nationwide network of Cold War-era Air Force nuclear-survivable radio transmitter sites into the network.