Garmin 198c sounder Manuale Proprietario

GPSMAP 198C Sounder Owner’s Manual

103

PPENDIX

HAT

WAAS

AND

DGPS?

What is WAAS?

The Wide Area Augmentation System (WAAS) is an F.A.A. funded

project to improve the overall integrity of the GPS signal. It is

a space-based system that broadcasts integrity information and

correction data as determined by ground reference stations. WAAS

testing completed in September 2003 conﬁrmed an accuracy of 2

to 3 vertical meters throughout the majority of the continental U.S.

and portions of Alaska. For more information, go to

http://gps.faa.gov/Programs/WAAS/waas.htm.

NOTE: If you are using the GPSMAP 198C Sounder outside

of the U.S.A., we recommend you turn off WAAS for the most

accurate location ﬁx.

What is Differential GPS (DGPS)?

The U.S. and Canadian governments (among others) have set up

Differential GPS (DGPS) stations to transmit correction signals.

They are operational in coastal areas and on many navigable river

systems. The DGPS system is available for use without a fee.
Refer to the U.S. Coast Guard’s Web site,

http://www.navcen.uscg.gov/ for locations and the status of the

differential sites. Using DGPS requires additional equipment.