With the cost of fuel and oil being what they are today, the extra wear and tear on your engines, it doesn't make sense to fish without one of these navigational devices. Safety is probably the most important reason to have one with you.

How does Global Positioning System (GPS) work?
The nominal GPS Operational Constellation consists of 24 satellites that orbit the earth. There are often more than 24 operational satellites as new ones are launched to replace older satellites. The satellite orbits repeat almost the same ground track (as the earth turns beneath them) once each day.

How accurate is GPS?
Civilians have access to the Standard Positioning Service (SPS). The SPS accuracy was intentionally degraded by the Department of Defense in 1994 to 100 meters. This inaccuracy is not a problem when fishing oil rigs offshore. It does present problems when trying to locate wrecks or other subsurface structure. It also creates a problem when using a GPS with a mapping display while fishing in the marsh.

What is DGPS and how accurate is it?
Differential GPS (DGPS) is a system designed to correct the various inaccuracies in the GPS system. Differential GPS involves the cooperation of two receivers, one that's stationary and another that's roving around (your boat) making position measurements. The stationary receiver in Louisiana is located in English Turn, just SE of New Orleans. The position of the fixed receiver is known and the inaccuracies of the position reported by the GPS system can be corrected mathematically. Since the "roving" receiver (your boat) is fairly close to the stationary antenna the same correction factors apply. These correction factors are then transmitted via a land-based antenna to your DGPS receiver and the corrections are applied. The result is a measurement good to a couple of meters. The data needed to set up your DGPS receiver in Louisiana is in the table below.

Standard readout or mapping display?
If you want to see where your are on a map overlay a mapping display is great. Lowrance Electronics recently came out with new mapping unit the GlobalMap 1600. The compact GlobalMap 1600 displays a brilliant built-in background map of the world with enhanced detail of lakes, rivers, streams, ponds, highways and roadways in North America, including the 48 contiguous U.S. States, Northern Mexico, the Bahamas, Hawaii and Southern Canada for true ease-of-use navigation. Lowrance has even included a built-in database of U.S. Navigation Aids to display lighted and unlighted buoys, navigation lights, day beacons, radio beacons and drilling platforms. You can fully maintain waypoint lists, create your own maps and then download all of the info from your computer into the GPS. This unit is awesome. To read more visit Lowrance Electronics. The GlobalMap 1600 can be purchased for $519.00, hand held units start at $149.00.

Where can you get GPS & DGPS "numbres"?
Click right here and visit the GPS are of Louisiana Fishing & Hunting or RodnReel.com as others call it. Everything you need to do some very productive rig selection prior to your next trip. Almost 4,000 (3,882) offshore oil & gas rigs in the Gulf waters off of Louisiana.

The data for each rig is:

• Rig Name
• Rig Owner
• Latitude suitable for GPS or DGPS
• Longitude suitable for GPS or DGPS
• Water depth at Rig
• Year rig was set in place
• Age of Rig
• A print feature for Black & White printers

For your personal safety, convenience and to save lots of money on fuel and oil it's time to get a GPS or DGPS today.