Lowrance electronic Lowrance iWAY 250C - Manual (Page 8)

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How Lowrance GPS and the GPS System Work
You will navigate a little easier if you understand the basics of how the
iWAY scans the sky to show you where you are and where you are go-
ing.
You will use the iWAY's touch screen to enter commands and control
its functions. As long as there is no interference
− and the unit is locked
on to a satellite signal − it will display your location on a moving map
and help guide you to your destination. A built-in speaker allows you to
hear verbal turn-by-turn driving instructions and listen to MP3 music
files.
The internal antenna tunes in to a couple of dozen GPS (Global Posi-
tioning System) and WAAS satellites circling the earth. The unit lis-
tens to signals from as many satellites as it can "see" above the horizon
then computes its location in relation to those satellites. The iWAY
plots your position on the map display on-screen. The iWAY's 2 giga-
byte SD Card contains highly detailed road and highway mapping data
either for the U.S. or Western Europe, depending on which version of
the unit you have purchased.
If you have purchased the U.S. version of the iWAY the SD card should
contain mapping data for Hawaii, Alaska, the 48 contiguous United
States and most of Canada.
If you have purchased the European version of the iWAY the SD card
should contain mapping data for Andorra, Austria, Belgium, Channel
Islands, Denmark, Germany, Greece, England, Finland, France, Gi-
braltar, Ireland, Isle Of Man, Italy, Liechtenstein, Luxembourg,
Monaco, Netherlands, Northern Ireland, Norway, Portugal, San Mar-
ino, Scotland, Spain, Sweden, Switzerland, Vatican and Wales.
CAUTION:
You must exercise care when using the SD Card with the map-
ping data because the data can be erased from the card. We sug-
gest you back up the SD Card mapping data to another card or
your home PC.
For the system to work the unit must have a clear view of the satellites.
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. If you would like to know more about GPS and its
companion system WAAS, visit our web site and check out the GPS
Product Guide section (www.lowrance.com/Support/gps.asp). It includes
a GPS tutorial, frequently asked questions and a glossary.