Wednesday, May 14, 2003


The GPS, or Global Positioning Satellite Network, is a network of satellites that transmits high-frequency radio signals containing time and distance data that can be picked up by a receiver, allowing the user to pinpoint their precise location anywhere around the globe. GPS originally had military applications - which were used with stunning accuracy during the current Iraq War. Munitions, guided by GPS receivers can hone in on it's target with classified accuracy of a few feet (or maybe even more).

Commercial applications have come about as a result of increased used of civilian bands of the system.

How Satellite Navigation Works
Global navigation satellites continuously transmit time and distance information as they orbit the earth in a precise formation. Navigation satellite receivers use this information to calculate an exact location through triangulation. Every point on Earth is identified by two sets of numbers called coordinates. These coordinates represent the exact point where a horizontal line, known as latitude, crosses a vertical line, known as longitude. The receiver locks on to at least three satellites and uses the information received to determine the coordinates of the device.

By comparing the time the signals were transmitted from the satellites and the time they were recorded, the receiver calculates how far away each satellite is. The distance of the receiver from three or more satellites reveals its position on the surface of the planet. With these distance measurements, the receiver might also calculate speed, bearing, trip time, distance to destination, altitude and more.

The satellite navigation device may display its position as longitude/latitude, Universal Transverse Mercator (UTM), Military Grid (MG) or simply as a point on an electronic map. Many Thales Navigation receivers provide comprehensive mapping data, making satellite navigation an easy tool to enhance your recreational and industrial activities.

So how does this relate to your average GPS user? Imagine going traveling to a part of the country, or world for that matter, that you are unfamiliar with. You key in the coordinates of where you want to go and of where you are and your GPS will tell you how to get there - right on down to telling you when and where to turn. General Aviation pilots have discovered the beauty of GPS as it is invaluable in aiding in navigation. Fishermen could concievably download coordinates from NASA Reconnaisance satellites of hard to find hot spots are for locating that great catch. Farmers could get updated GPS information for where richer farmsoil is on their land. Oil companies could pinpoint pockets of crude for drilling.

GPS has an unlimited amount of potential for the business world.

Magellan's GPS Companion (I tested it for the Visor PDA) works great. You set it up by establishing a fix. Click the general location on a global map and then again on a national map. Then key in your elevation/altitude above sea level. The GPS gets a fix and you know where you are on the big, blue marble. Hop in the car and it tells you not only where you are (via longitude/latitude coordinates) but how high you are, how fast you are travelling, and what direction you are heading.

That's the beauty of GPS.

The only downside to the Magellan GPS is that the available maps used in it's Nav software are sparse and simplistic. If you are expecting to see detailed map as you follow it, you'll be disappointed. Pocket PC variants have greater detail.

Is it a toy? Sure it is. A very cool one. But it's also a tool which has specific applications for specific users.


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