Sat navs: Jargon buster
Bluetooth is a wireless technology that lets a sat nav communicate with a mobile phone. Some sat navs can be set up to act as hands-free kits - a legal alternative to using your handset at the wheel.
The estimated time of arrival, usually shown in hours and minutes on your sat nav, tells you how long it will take you to reach your destination under current driving conditions.
Heavy traffic, bad weather and wrong turns can all increase your journey time.
Sat nav systems detect where your car is using global positioning system (GPS) technology.
Satellites orbit around the Earth and communicate with each other – and your sat nav – to provide your location.
This is TomTom’s name for its traffic information service. It is sophisticated, drawing on data from several sources to map real-time traffic hotspots and then calculate a route round them.
Points of Interest
These are locations on your map that may be of interest – petrol stations, railway stations, restaurants and hospitals are some of the most common ones. Many are pre-installed on your sat nav, but you can add more if you wish, from supermarkets to DIY stores. Over time, you can update them when you update your maps.
Mobile phone sat nav apps also display contact information for the point of interest and enable you to call it on your phone.
A smartphone is a high-end mobile phone. Many of them feature GPS technology. Download as app and it can be used as a sat nav.
Traffic information is used by your sat nav to help you avoid jams and troublespots.
Some sat nav makers offer traffic information for free, but with most systems it is an optional extra, paid for via a one-off fee, or a monthly or annual subscription.