Motorola DROID 2 Global, Руководство пользователя

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Chapter
Finding Your Way With
Maps
One of the big advantages of owning a smartphone is that, not only do you have a
mobile computer with you at all times, but you also have a compass, map, and
restaurant guide.
This chapter will discuss using Google Maps and other location-conscious apps on your
phone for both business and pleasure. You’ll learn how to use your phone for driving
directions, deciding where to eat, and letting your friends know where to find you.
There are a lot of apps that use maps, but in order to do so, those apps have to know
where your phone is. In general, phones know where they are by using the following:
GPS (global positioning satellites)
Cell phone towers
WPS (Wireless Positioning System)
There are dozens global positioning satellites orbiting the Earth. Your DROID’s GPS unit
attempts to find the signal from at least three of them and triangulate your position.
However, this requires your phone to have a chip that detects GPS signals and be in an
area that can detect them. If you’re indoors underground or around lots of tall buildings,
your phone might not pick up a GPS signal.
Your location can also be estimated using relative positions to cell phone towers. This
isn’t as accurate as GPS because cell towers are positioned for better signal reception,
not triangulation, so there are generally not three overlapping points for positioning.
The third method of locating your phone comes from using a map of known public Wi-Fi
spots. It’s a method that works well in urban areas and indoors – precisely the places
where GPS does poorly. Because it only requires a Wi-Fi signal, it even works on
laptops, netbooks, and tablets.
If you combine all three methods, you end up with a phone that usually knows where it
is.
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