Lowrance electronic 540c Baja - Manual (Page 12)

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NOTE:
The above memory capacities refer only to the GlobalMap's on-board
memory. The amount of GPS data you can record and save for recall
later is limited only by the number of MMC cards you have.
How Lowrance GPS Works
You'll navigate faster and easier if you understand how the GlobalMap
540c BAJA scans the sky to tell you where you are and where you're
going. (But if you already have a working understanding of GPS receiv-
ers and the GPS navigation system, skip to Section 2, Installation &
Accessories on page 11. If you're new to GPS, read on, and you can later
impress your friends with your new-found knowledge.)
First, think of your unit as a small but powerful computer. (But don't
worry — we made it easy to use, so you don't need to be a computer ex-
pert to find your way!) The GlobalMap 540c BAJA includes a keypad
and a screen with menus so you can tell it what to do. The screen also
lets the unit show your location on a moving map, as well as point the
way to your destination.
This gimbal-mounted GlobalMap 540c uses a LGC-BAJA module,
which makes the whole system work something like your car radio. But
instead of your favorite dance tunes, this receiver tunes in to a couple
of dozen GPS satellites circling the earth. (It will also listen in to the
WAAS satellites in orbit, but more about that in the upcoming segment
introducing you to GPS and WAAS.)
Your unit listens to signals from as many satellites as it can see above
the horizon, eliminates the weakest signals, then computes its location
in relation to those satellites. Once the GlobalMap 540c figures its lati-
tude and longitude, it plots that position on the moving map shown on
the screen. The whole process takes place several times a second!
The performance doesn't stop there. Stored in the permanent memory
of each unit is a basic background map of the entire world. We lock it in
here at the factory — you can't change or erase this map.
The background map is suitable for many navigation chores, but for
maximum accuracy and much more detail, you need our optional map-
making software, MapCreate
™ 6. Some unit features — such as search-
ing for businesses and addresses — won't work without a custom Map-
Create map. There is so much detail in our background map (and even
more in MapCreate) that we'll describe their contents and differences
in Section 3, Basic GPS Operations, on page 36.
Another portion of your GlobalMap’s onboard memory is devoted to re-
cording GPS navigation information, which includes waypoints, event