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What It Is and How It Works - For the uninitiated, GPS stands for Global Positioning System. It's a way of locating a receiver in three dimensional space anywhere on the Earth, and even in orbit about it, and it's probably one of the most important inventions of the 20th century. GPS can be used in so many varied ways that new technologies are constantly being developed and improved in order to take advantage of it. Now why is GPS so important and useful? First, we have to understand how it works.

In order for GPS to work, a network of satellites was placed into orbit around planet Earth. These satellites each broadcast a specific signal, which is received by inexpensive aerials and passed on to GPS devices where it is then decoded and used by dedicated software. The information is specific enough that the GPS software can identify the satellite, it's location in space, and calculate the time that the signal took to travel from the satellite to the GPS receiver. Using different signals from different satellites, the GPS software can now analyze the position of the receiver, in terms of latitude and longitude.

Mapping It Out - Knowing where the device is in space is one thing, but it is fairly useless information without something to compare it with. This is where the mapping comes in handy; thru this, GPS can analyze our location and maps out possible routes. Actually, the mapping data is what makes a GPS device expensive. It must be accurate and updated reasonably frequently.

Several kinds of maps are created for different users. Road users need maps containing accurate data about the road systems in their particular region, but they won't need data about the lay of the land. Hikers, however, might require a more detailed map about the local terrain, water spots, and tracks or trails, but they won't need extensive information about the road systems. Marine users need very specific information relating to the sea bed, navigable channels, and other pieces of maritime data that enables them to navigate safely.

And what about fishermen? They also use marine GPS to keep track of the movements of fish in real time and to predict where they'll be the next day. The advent of GPS fixing has also meant that co-operative fishing has become much easier, where several boats relay their locations to each other while they locate the best fishing waters. There are also GPS devices called 'fish finders', which combines GPS and sonar functions to track and store detailed fishing and maritime information.

Get Started with GPS - Consumers can avail of several GPS devices that are specifically designed for a variety of uses and functions. In-car systems have advanced features like voice guidance, dynamic route calculations, and even upgrading your maps from a CD-ROM. Then there are handheld GPS devices, such as those from Magellan and Garmin, which store a map inside, and are usually designed for outdoor use. They generally do not have any road information, and leave the users to find their own way from A to B.

A more recent solution has appeared on the market which uses the power of a PDA to run the actual GPS software. A GPS receiver can be easily attached to these devices, so these tend to be the cheapest, easiest to use and most flexible solutions. Bluetooth technology has also started to make use of GPS, by having several receivers with Bluetooth capabilities, and a single PDA.