NAVCEN operates the Coast
Guard Maritime Differential GPS (DGPS) Service and the
developing Nationwide DGPS Service (NDGPS), consisting
of two control centers and 86 remote broadcast sites.
The Service broadcasts correction signals on marine
radiobeacon frequencies to improve the accuracy and
integrity to GPS-derived positions. The Coast Guard
DGPS Service provides 10-meter accuracy in all established
coverage areas.
Typically, the position error of a DGPS position is
1 to 3 meters, greatly enhancing harbor entrance and
approach navigation. The System provides service for
coastal coverage of the continental U.S., the Great
Lakes, Puerto Rico, portions of Alaska, Hawaii, and
a large part of the Mississippi River Basin. Many foreign
nations are implementing standard DGPS services modeled
after the U.S. Coast Guard’s system to improve
maritime safety in their critical waterways.
|
DGPS is an all-weather system
|
| The Coast Guard's maritime Differential Global Positioning
Service achieved Full Operational Capability (FOC) on 15 March
1999 as announced in the DOT press release. The maritime DGPS
service provides 10 meter (2 dRMS) navigation accuracy, integrity
alarms for GPS and DGPS out-of-tolerance conditions within 10
seconds of detection, availability of 99.7% per month, coastal
coverage to the continental United States, the Great Lakes,
Puerto Rico/US Virgin Islands, and selected portions of Alaska
and Hawaii.
The achievement of FOC culminates a six-year effort to convert
existing radiobeacon sites and construct new sites to transmit
DGPS corrections. Several equipment upgrades were installed
to improve system performance. During the procurement and
installation phases of the system upgrades, the maritime DGPS
service operated under Initial Operational Capability rules,
where the signals provided accurate corrections with integrity
to the maximum extent possible.
|
