What It Is and How It Works ? For those who are unfamiliar with the term, 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 to work, a satellite network orbiting the earth is used. 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 garnered from these signals allows the GPS software to identify the satellite, its specific location, and even calculate the exact time it took for the signal to travel from the satellite to the receiver. Using different signals from different satellites, the GPS software is able to calculate the position of the receiver.

Mapping It Out ? Even getting the information about the receiver's location will be useless 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, for example, require that their mapping data contains accurate information about the road network in the region that they will be traveling in, but will not require detailed information about the lie of the land. On the other hand, hiking GPS users might wish to have a detailed map of the terrain, rivers, hills and so forth, and perhaps tracks and trails, but not roads. 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. Special kinds of marine GPS, known as fishfinders, also combine several functions in one to help fishermen.

Get Started with GPS ? Consumers can avail of several GPS devices that are specifically designed for a variety of uses and functions. Sophisticated in-car GPS systems, which feature voice guiding, powerful dynamic route calculation, and the possibility to update the map from a CD, are now available. 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 do not have detailed road information and the user has to find his own way from point A to point B without any route calculations.

Recently, PDAs and even a few sophisticated mobile phones have incorporated GPS technology into their own systems. A GPS receiver can be easily attached to these devices, which makes them possibly the cheapest and easiest GPS receivers to use in the market today. Bluetooth technology has also started to make use of GPS, by having several receivers with Bluetooth capabilities, and a single PDA.