GPS - Basic Definition

1.Basic Definition of GPS
By James D. Allen

GPS (Global Positioning Systems) have been around for quite some time now. Its first use was with the military, but they have more recently been associated with civilian navigation devices. The latter is the topic of this discussion.

There are three components necessary for the success of a Global Positioning System. Those components are made up of 24 satellites, GPS Receivers, and ground stations. Each component must work in harmony or there will be inaccurate readings. A brief description of each and their functionality follows.

GPS Receivers act just as their name indicates. They receive information from the chosen satellites using radio waves to calculate their exact location. Once this information has been received, feedback is provided to the user.

Ground stations have a two-fold operation. The first is to ensure the health of the satellite. The second is to respond to the satellite with its exact location. This location is very important as it is used to later determine the exact coordinates of a GPS device.

Satellites determine the coordinates of a GPS device using trilateration. Basically, three satellites use radio signals to determine the total distance from the GPS device. This can become very complicated because of a variety of interference possibilities. Therefore, most civilian GPS systems use additional satellites to increase accuracy.

GPS systems continue to grow in popularity. There is a belief they will one day be as common as the telephone or television. There is also a belief that the high popularity will help to push builders into furthering the technology with improvements much in the same way as the cellular phone in recent years.

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2. How It Works
By David Stone

GPS or Global Positioning Systems are computer systems that use satellites in orbit around the globe to provide exact longitudinal and latitudinal position of the user. GPS units were originally designed by the Department of Defense for military purposes and are now used on the consumer level for day to day navigation. Some GPS units sell for less than $100.00 and as long as you have one and have a clear sight of the sky you will never be lost again. In fact most GPS receivers can pinpoint your location on the globe within about 50 feet. GPS units vary in price based on their quality and capabilities, so when shopping for one it is important to know what you are planning to use it for.

GPS systems are mostly used by consumers for two purposes, positioning and navigation. GPS units are placed on boats so boaters can have an idea of where they are in comparison to the shoreline. In cars they are more often equipped to provide directions to the driver from two different points. Some of the more expensive models come equipped with voice capabilities so that drivers don't even have to take their eyes off the road. Many handheld models are sold to outdoor enthusiasts for camping, hunting and hiking. These handheld models also range in price based on their capabilities and if the display comes in color or not.

Most GPS units will also provide you with some standard and useful information…..

· An Odometer (Distance you have traveled)
· Time you have been traveling
· A Speedometer (How fast you are currently traveling)
· Average speed for the journey
· A map of you trail so far
· E.T.A (Estimated time of arrival)

GPS units use four satellites orbiting the globe to triangulate your position on earth and can do so with extreme accuracy. If you are constantly lost behind the wheel or spend a lot of time in the outdoors purchasing a GPS unit might be the right move for you.

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