DGPS Beacons (cont’d)
FLORIDA
Broadcast site FREQ. TRANS. RATE RANGE LAT./LONG.
Cape Canaveral 289 kHz 100 BPS 200 M 28 27.6N, 80 32.6W
Miami 322 kHz 100 bps 75M 25 44.0N, 80 09.6W
Key West 286 kHz 100 bps 110M 24 34.9N, 81 39.2W
Tampa 312 kHz 100 bps 386M 27 51.0N, 82 31.9W
ALABAMA
Millers Ferry 320kHz 150M 32 5.4N, 87 23.5W
Mobile Point 300 kHz 100 bps 170M 30 13.7N, 88 01.4W
LOUISIANA
English Turn 293 kHz 200 bps 170M 29 52.7N, 89 56.5W
TEXAS
Galveston 296 kHz 100 bps 180M 29 19.8N, 94 44.2W
Aransas Pass 304 kHz 100 bps 180M 27 50.3N, 97 03.5W
BERMUDA
St. David’s Head 323 kHz 100 bps 100 32 22N, 64 38W
*Transmissions from this site may be intermittent and turned off without warning.
WAAS GPS
mation to be downloaded to an electronic
charting program and can integrate radar,
The Wide Area Augmentation System is an
weather, AIS and other information into one
enhanced GPS system being implemented by
screen display.
the Federal Aviation Administration.
There are two NMEA standards currently
Similar to DGPS, WAAS uses precisely sur-
in use: 0183 and the newer 2000. NMEA
veyed ground stations to transmit GPS cor-
2000 is substantially faster and allows several
rections. However, WAAS stations uplink the
units to communicate or interface at the
corrections back to satellites that then broad-
same time. The types of plugs and wiring
cast corrected GPS data. This makes the cor-
required by the standards are different, so
rected signal available everywhere instead of
pay close attention when choosing new gear GPS
just within range of the ground stations.
to add to an existing system.
WAAS is intended for aviation, but WAAS
Fixed systems use an external antenna
capability is now common on most marine
that must be mounted, usually on a railing.
GPS receivers.
Handhelds have integrated antennae, but ion
GPS Receivers some offer the option of connecting to a re-
at
GPS receivers come in the form of per-
mote antenna for better reception.
manent installations or portable handheld
The simplest handheld GPS units will store
a
v
ig
units. Some receivers display no information
waypoints and establish routes, but not dis-
N
directly to the user but relay data to other
play nautical charts. Those that can display
systems integrating radar and chart infor-
charts do so via internal memory or by ac-
mation. Combined with electronic charting
cessing the charts on some kind of disk or
functions, the variety of bells and whistles
cartridge. Those with internal memory have
available today is nearly endless, but even
the ability to download charts from another
the least expensive handheld units display
source, like a personal computer.
information on direction and distance to
No single type of receiver is right for every
waypoints, speed and cross-track error.
sailor. Choosing one depends largely on how
Most marine GPS units include an outlet
you wish to incorporate information from
for connecting to a personal computer or
the GPS into your navigation methods. The
other electronics. These are referred to as
techniques for using GPS are as varied as the
NMEA ports, as the National Marine Elec-
equipment for sale.
tronics Association establishes the electronic
Since GPS is now extensively used for over-
standards for communication between the
land navigation and automobiles, sailors
units. A NMEA port allows position infor-
shopping for a GPS unit must be wise to
avoid units configured for other uses. Many
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