Gps Features, How They Work And What To Consider When Buying.

GPS devices work by receiving signals from satellites in the Navstar GPS network that consists of 30 satellites orbiting the earth every 12 hours and 5 ground stations that monitor their positions in space. In order for a GPS device to work effectively it must receive signals from at least 4 of these satellites to get what is called a 3D fix and to do this the GPS's antenna needs an unobstructed view of the sky. The GPS unit uses a computer with software containing map files and other data to compare the information it gets from the satellites in order to show your current position in real time. How well your GPS works will depend on the quality of the receiver and location of the antenna. The satellite signals can also be blocked by geographical features such as heavily wooded areas, buildings, overpasses, tunnels etc.

There are many models of GPS to choose from, some are meant to be installed in a vehicle while others are more portable for pedestrian use while some have features of both such as voice prompted turn by turn directions, detailed street maps and point of interest databases yet are small enough to fit in your pocket.

Some features to look for in a GPS would include a good color screen that can be viewed in all lighting conditions, including direct sunlight, and from various angles.

You should look for a model that has street level maps if you intend to use it for vehicle navigation. This information could be acquired in different ways. Some portable models use a method where you plug the GPS into a USB port on your computer to download the latest software and maps while some in dash types may use CD-ROM discs to get this information and other smaller models may use memory cards. Depending on the manufacturer, you will probably have to pay some type of fee to access this information. In general GPS systems that use NavTeq or TeleAtlas digital maps are some of the most accurate for mapping detail.

Most GPS units have the standard features such as text prompted generic driving instructions that give directions in measured distance from point to point or turn to turn but some of the newer models are more sophisticated with street names and point of interest databases such as airports, hospitals, gas stations, restaraunts and shopping locations. This is especially helpful when traveling in unfamiliar locations. This is also true of automatic routing capabilities where the device can give you a route from point to point such as locations in your address book or your present location to other points of interest. You should also look for automatic rerouting capabilities where you can get a new route from your present location if you happen to take a wrong turn for some reason and get off course. You can program your route ahead of time choosing to take the shortest or quickest path and even tell the GPS to avoid certain streets if you have reason to believe there may be construction or other traffic problems. Some of the better or more expensive models have voice guided directions that will give you advance notice of turns you need to make next after you complete each maneuver and if your device has text to speech ability it can give you the actual street names you should be looking for.

Your GPS could also have touch screen controls, variable map perspectives such as 3D and bird's eye views and real time traffic and weather alerts. These last two will probably require a paid subscription service. You may be able to get auxiliary antennas that mount at the base of your windshield to improve signal reception or low profile external mounting kits that allow you to mount your antenna on the rear trunk lid.

No doubt there are many things to consider when looking for a GPS unit. You should start by considering just what you will be using it for and how portable it needs to be then consider how much you want to spend. After you determine these factors then you should look at what kind of features you can get for the money you have to spend and be sure to check several different brands and models befrore you decide.

Written by Steven W.

By: Steven W.

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