An increasing number of motorists these days are turning to the very latest technology to make their journeys a whole lot easier. This is satellite navigation or global positioning systems (GPS). It has a recent but fascinating history. The system is based on a number of satellites originally intended for military purposes, sent into orbit by the US Defence Department. In the mid 1980’s the US Government allowed the system to be used for civilian purposes and so commercial – portable and in car navigational aids became available to anyone to purchase.
Briefly, the GPS satellites circle the globe twice every 24 hours. They constantly emit signals that are received by the GPS units on earth. By a simple method of triangulation, the unit instantly calculates its precise position.
The receiving unit contains electronic mapping information. Before commencing a trip, the user enters the details of the intended journey in very much the same way as when using the RAC or AA route planners. The unit has a screen that shows an up to the minute map of the route and the vehicle’s position is continuously displayed as the journey progresses. The unit allows for speed variation when making its calculations and most modern systems have a voice synthesiser that provides advanced warning of the need to take a turn. The driver can therefore see exactly where he or she is on their journey and be secure in the knowledge that they are unlikely to take a wrong turn or get lost.
GPS works in all weather conditions and will operate equally well in heavily built up areas and dense forest conditions. Once the receiving unit has been obtained and fitted, there are no further costs involved. They are extremely accurate and with the introduction of new technology in the form of the Wide Area Augmentation System or WASS and differential GPS, users can be sure of their position to within three to five meters.
GPS units are now widely available and many car manufacturers are offering them as options in their vehicles. As the technology becomes mor familiar, the price lowers and the features improve. GPS has been an invaluable tool for the military and the emergency services for many years. It is becoming equally indispensable to the civilian traveller of the 21st century.