Nowadays, almost all drivers use Global Positioning System (GPS). This technology indeed has brought people much convenience. With GPS, drivers no longer need to worry that they may get lost. GPS can easily tell them where they are and how to reach destination. Let's see how this fantastic technology work.
In simple terms, Global Positioning System defines the location of the GPS receiver according to four satellites whose positions are known.
As this picture shows, the receiver is the position we need to define, and the 1, 2, 3, 4 are four satellites we use. Position1, Position2, Position3, Position4 are coordinates of these satellites. d1, d2 d3, d4 are distance from the four satellites to the receiver, respectively. Location is the position of receiver we need to define. The process of defining the location, simply, is using an algorithm GetLocation() to get the value of Location.
Location = GetLocation([Position1, d1], [Position2, d2], [Position3, d3], [Position4, d4]);
So far, Global Positioning System has been widely used, both in civilian and in military.
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Picture Reference:
1.http://images.cnblogs.com/cnblogs_com/magicboy110/Windows-Live-Writer/GPS_3B2/GPS_thumb22_thumb.png
2.http://www.extremetech.com/wp-content/uploads/2012/04/gps-satellite-constellation.jpg
Writing Reference:
http://www.cnblogs.com/magicboy110/archive/2010/12/09/1901669.html
Writing Reference:
http://www.cnblogs.com/magicboy110/archive/2010/12/09/1901669.html
Interesting entry. I never really understood how fragile the basic algorithm for GPS is--one incorrect or misplaced number and the whole thing would fall apart. I guess all programs are like that, I guess, but it's still weird to think about just because of how essential GPS has become in our day-to-day lives. Also, looking at the picture you provided, there are probably waaay more satellites around the earth than I'd assumed.
ReplyDeleteYes, the picture is just a simplified model.
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