How Portable GPS Units Work

in Gps

I remember taking a road trip with my daughter who was then four years old just after I got my portable GPS unit installed into my car. I said, "look baby, that dot shows exactly where we are." To which she quickly replied, "Daddy, how does it know that?" Well, since she was only four years old, I had to explain it in a way that she could easily understand.

"Our position, as it relates to our exact location on the earth, is triangulated by the use of at least 24 GPS, or global positioning system, satellites that have been secured in space at locations so as to be able to cover the entire surface of the globe. These satellites are constantly sending signals to Earth that are then picked up by GPS receivers, such as the one installed on the car's dashboard. Because this is a receiver, it only accepts the information that is transmitted to it by the GPS satellite. Once a portable GPS unit has received data from the satellite, the satellite then knows exactly where that unit is on the earth. Because this process is not exact and can only give position within 10 to 20 meters or so, it is necessary to use one of five ground-based satellites to help further pinpoint the location of the GPS unit. By using data from satellites in space as well as on the ground, it's possible to locate our position within an area as small as 1 meter.

Once the exact position of the GPS unit has been triangulated through the use of GPS satellites, this data is then overlaid on an electronically created map that exists as part of the unit itself. As long as the device remains in contact with the satellites, we will be able to use this information to plan our driving route and get to our destination no matter where it is on the earth."

After giving this explanation, which I thought was more than general in nature, my little baby girl looked at me again, cocked her head to the side, and said, "So, how does it know where we are?" "It's magic..." I said, and this seemed to satisfy her just fine...GPS units ARE like magic and I am more than happy I purchased one for the ability to magically appear at the location of my choice without getting lost for a change.

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Alex McGaw has 1 articles online

Alex McGaw writes about saving money shopping online. For more tips on Portable GPS Units, visit TomTom GPS Deals. This website offers you the lowest prices on GPS units, GPS cases, GPS chargers and other accessories.

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How Portable GPS Units Work

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This article was published on 2010/03/31