Operating Instructions and Installation Instructions

Remember, the unit must have a clear view of the satellites in order to

receive their signals. Unlike radio or television signals, GPS works at

very high frequencies. These signals can be easily blocked by trees,

buildings, an automobile roof, even your body.

Like most GPS receivers, the unit doesn’t have a compass or any other

navigation aid built inside. It relies solely on the signals from the satel-

lites to calculate a position. Speed, direction of travel, and distance are

all calculated from position information. Therefore, in order it to de-

termine direction of travel, you must be moving and the faster, the bet-

ter. This is not to say that it won’t work at walking or trolling speeds —

it will. There will simply be more "wandering" of the data shown on the

display.

GPS alone is plenty accurate for route navigation, but the U.S. Federal

Aviation Administration has special aircraft navigation needs that go

beyond basic GPS. So, the FAA has developed a program to boost GPS

performance with its Wide Area Augmentation System, or WAAS. The

FAA commissioned the system on July 11, 2003.

WAAS is designed to increase GPS accuracy to within 7.6 meters vertically

and horizontally, but it consistently delivers accuracies within 1-2 meters

horizontal and 2-3 meters vertical, according to the FAA. It does this by

broadcasting correction signals on GPS frequencies. Your unit automati-

cally receives both GPS and WAAS signals.

However, there are some fringe areas of the U.S., including parts of

Alaska that do not yet receive robust WAAS coverage. Continued WAAS

development is planned to extend WAAS coverage in the years to come.

WAAS boosts the accuracy of land GPS navigation, but the system is

designed for aircraft. The satellites are in a fixed orbit around the

Equator, so they appear very low in the sky to someone on the ground

in North America. Aircraft and vessels on open water can get consis-

tently good WAAS reception, but terrain, foliage or even large man-made

structures can sometimes block the WAAS signal from ground receivers.

You'll find that using your GPS receiver is both easy and amazingly

accurate. It’s easily the most accurate method of electronic navigation

available to the general public today. Remember, however, that this

receiver is only a tool. Always have another method of navigation avail-

able, such as a map or chart and a compass.

Also remember that this unit will always show navigation information

in the shortest line from your present position to a waypoint, regardless