Sat nav systems are one of the biggest breakthroughs in navigation technology and after being used for years for military application, they have in the last few years become available for civilian drivers. Satellite systems are often fitted as standard in cars and it is thought that within the next 10 years, 90% of cars will have them.

Satellite navigation is powered by GPS (Global Positioning System). GPS is a collection of over 2 dozen satellites which orbit the earth, sending exact timing signals by radio transmission whereby GPSr (Global Positioning System Receiver, ala you're Satellite Navigation System) will be able to determine its location within a few metres.

Satellite navigation systems can be purchased from most good car shops for anywhere between one to a few hundred pounds. Sat nav systems come in a whole variety of forms, from full systems which are wired into the car, to ones which are simply mounted onto the dash board or other appropriate space, which can be taken out and fitted into another car within seconds. These types of satellite navigation systems are usually plugged into the cigarette lighter socket and powered in this way, whilst the fitted systems are hardwired into the electrics of the car.

Price, as always, plays a big part in the quality of your satellite navigation system. Cheaper systems, particularly the earlier GPS in-car systems, would malfunction and for various reasons the mapping would be out of date and other errors would abound. Since in-car GPS has been around for a few years now it has had time to be refined immensely, making such rudimentary issues more or less a thing of the past. Many people may find it difficult, if not unnerving to visually read a GPS system's on screen information whilst driving, so there is always the option of purchasing a more expensive unit which will talk to you whilst you drive, giving you audible directions and information.

If you want a good, reliable GPS system, you should check out some of the review sites on the internet where buyers and owners have written about their own experiences with their systems, which may help you to make the choice of which one to purchase yourself.