GPS: Get Lost – Not!

By bolc6745


Do you know where your child is?  Do you care?  If your child is lost or kidnapped, would you like to know his or her exact location?  If this sounds interesting to you, you should read my report to find out how awesome GPS can be. I will teach you what GPS is.  We will talk a little bit about the history of GPS.  Finally, I will teach you how it works.  Hang on!  WeÕre on for a wild ride! 

What is GPS?

Many people have heard of GPS, but they donÕt know what it is. According to Allison K. Brown, GPS stands for Global Positioning System.  It is a worldwide system that helps you know where you are, on the earth.  It is operated by the United States Air Force, but the military and normal people use it.

When people say GPS, do they mean the satellites or the receivers? Many people donÕt even know the difference.  The satellite is the thing that sends the signals to earth.  The receiver is the thing that gets the signal and figures out where, on earth, you are.  The satellites are huge and expensive.  The receivers are small enough to carry and cost between $50-$300.

Topic Sentence.  Finish paragraph.


Does anyone really know who invented GPS?  Marshall Brain says that the U.S. military invented GPS .They invented it to help soldiers find out where, on earth, they are.  Now, everybody else can use GPS.

Topic Sentence.   Finish the paragraph.

How GPS Works

GPS uses satellites that send signals. According to Digital Graphics Research Corporation, GPS works by using about 30 satellites floating around the earth.  They send radio waves down to earth (your receiver will need to get radio waves from 4 or 5 satellites).  It is very accurate and can figure out where you are within 10 meters.

GPS satellites are interesting.  According to Allison K. Brown, GPS uses 24 satellites within 6 orbits.  They are over 10,000 miles high.  From anywhere on earth, you might, if you're lucky, be able to have access to 8 of these satellites.

GPS has a few limitations.  Digital Graphic Research Corporation says that radio waves travel in straight lines.  These waves cannot pass through hard surfaces like metal or rock very easily.  So GPS has a hard time working in a tunnel or in a city with really tall buildings.  Sometimes, hikers will have trouble with their GPS if they are under big trees.

How does GPS figure out where you are?  According to Brian Marshall, GPS uses a fancy math called trilateration.  A GPS receiver (the thing you hold in your hand or it's in your car) is supposed to receive signals from at least three different satellites and figure out how far away it is from each of them.  It then uses math to figure out exactly where it is.

Topic Sentence.  Finish the paragraph.


In conclusion, you might consider how important GPS is to us in this modern age.  Remember, GPS is a global system that tells you where you are.  It was invented by the military, but is used by anyone who wants to.  And, it works by using satellites and a fancy math called trilateration.  Now go get lost – NOT!




Brain, Marshall and Harris, Tom

How GPS Receivers Work

May 11, 2006

This is a 6-part article that tells ALL about GPS:  how it works, trilateration, etc.



Brown, Allison K.

Global Positioning System

May 11, 2006

This article tells how GPS works and who uses it.  It gives information about the satellites and tells how accurate it can be.



Digital Graphic Research Corporation

Budding Geographers: How Does GPS Work?


This article is written for kids.  It teaches kids who interested in Geography how GPS works.  It uses a great "Marco Polo" example to teach trilateration.