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Tips on Buying Your First GPS Unit
If you are in the market for a GPS device, it is important that you understand how it works. Since the GPS devices rely on air signals, you must have a GPS receiver and a clear view of the sky for them to work. When your device is turned on it is actually linking up with 27 orbital satellites in place around the planet. Four of the nearest satellites are located and the distance from them to you is calculated via the hand held device. The process is called trilateration. Based on that, the GPS device can determine where you are on the planet.
Free GPS Software
There are online sites that list various free GPS software and describe how to use the programs after you download them. Often individuals who have used the programs themselves develop the sites. These are great because they give you an unbiased interpretation of the benefits and disadvantages of the programs before you use them. Using free GPS software you can download programs that allow you to retrieve and display aerial photos, topographical maps, USGS landmarks. There are programs available that allow you import scanned images and add latitude and longitude points and other data.
GPS Cell Phones
Cell phones are already available with GPS technology installed. These systems are not the same as the GPS devices used by hikers, mariners and drivers. Lower cost models do not allow the user to enter data such as mapping software. All systems require a wireless network.
How GPS Works
Global Positioning System (GPS) is a navigational aid originally developed for the military. The system simply receives signals. It is the applied technology that gives the GPS its versatility. If you have ever used map and compass, you will understand a little about how the GPS works. In order to find your position on a map, you need to have three points of reference. The intersecting line from the reference points is where you are. Map and compass work uses triangulation (bearings), GPS uses trilateration (distances) to calculate location. Satellites orbiting the earth emit unique signals that can be received by a GPS. The GPS software interprets the signal, identifying the satellite that it came from, where it was located, and the time that it took for the signal to reach the system. Once the receiver has both time and distance it begins to determine position.
Buying a Satellite Navigation (Satnav) System for Your Car
SatNav is a system that comprises of 2 elements, a GPS data receiver and a CPU/display unit. The receiver gets information from orbiting GPS navigational satellites and communicates it to the CPU/display unit. This unit is then able to find its exact location on the planet by comparing signals from various satellites.
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