Satellite Navigation devices are very popular among motorists in the UK because of their ease of use. Drivers are able to jump into their car, enter their desired destination and set off, leaving the Sat Nav to direct them with turn-by-turn instructions at junctions and roundabouts, on to the final location.
At the core of the satellite navigation unit is NAVSTAR also known as GPS (Global Positioning System) established by the United States Military in the 1970s to enable soliders to know their exact location anywhere in the world, as well as to improve the accuracy of missiles. In 1994 President Bill Clinton felt that GPS could be used for civilian purposes as well as for the military, and so he opened GPS up to the public free of charge. Since then a number of different devices and uses have appeared for private and commercial use.
Sat Navs use GPS to determine their location within a few metres anywhere on the planet whether on land, sea or air. Satellite Navigation units will normally use this information to display the current location on a digital map using the corresponding longitude and latitude so the user can clearly and visually see their location. When you have programmed a route into the device it will typically highlight the roads and show the path you will need to take as well as giving verbal instructions for example "take the next left" and "take the third exit on the roundabout".
Most of the Satellite Navigation devices on the market today will use one of the two leading digital mapping solutions, Navteq or Teleatlas and have options of either 2D or 3D map display. Other features normally found on sat navs are options for Day and Night mode which will reduce the colours to make it less intrusive during darker road conditions, and the ability to select a Place of Interest (POI) from a built-in list of attractions, and useful locations such as petrol stations and hotels.
Satellite Navigators are becoming popular in other areas such as the aviation industry, mostly for light aircraft pilots, and Marine industry for sailors to navigate channels in their personal pleasure crafts. Products such as the Road Angel Adventurer 7000 allow the user to load CAA Aviation Charts and Maptech Marine Charts as well as the Ordnance Survey Landranger maps covering all of the national parks. Other devices such as the Snooper Truckmate Pro S8000 have versions specially designed for Commercial Vehicles such as lorries which warn of low bridges and change speed limits for those of heavy goods vehicles.
There are some people who have criticised Satellite Navigators for taking people down unsuitable roads, such as taking lorry drivers through small villages. There is also the argument that Sat Navs could distract the drivers attention away from the road in a similar way to mobile phones and thus cause the driver to have an accident.
Because Satellite Navigation has become so popular all over the world, many countries are not happy about being so dependent on the USA and their NAVSTAR system, and so there are a number of countries currently planning and developing their own alternative systems. The European Union is planning a GPS version named Galileo which is due to be ready after 2012, the receivers are expected to be compatible with both Galileo and GPS. China is currently planning to expand their regional system into a global system. China is said to be in talks with the EU about joining the Galileo project.