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 has so many different applications that many technologies and ways of working are continually being improved in order to make the most 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. The signals that are broadcast by the satellites carry data that is passed from the aerial, decoded and used by to the GPS 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 is able to calculate the position of the receiver.

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. 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. On the other hand, sailors will need specific data about the sea bed, navigable channels, and other related information that will allow them to navigate safely.

Fishermen also use marine GPS to locate themselves and track the movement of shoals of fish both in real time, and to predict where they will 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. In-car systems have advanced features like voice guidance, dynamic route calculations, and even upgrading your maps from a CD-ROM. Rugged handheld GPS devices, like those from Garmin and Magellan, have a map inside and are usually used for outdoor activities. They generally do not have any road information, and leave the users to find their own way from A to B.

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, so these tend to be the cheapest, easiest to use and most flexible solutions. Bluetooth technology has also started to make use of GPS, using a single PDA device wirelessly connected to several receivers.