A Sat Nav system is an integral part the in car entertainment system and is generally set within the dashboard and centre console area. The main sat nav unit is often integrated with the car stereo with a large screen set into the central area of the dashboard. Most modern sat nav systems utilise a touch screen and in some cases this is used to navigate and control other systems of the vehicle such as audio, suspension or gearbox settings (vehicle specific).

The Sat Nav system is connected internally to a GPS device which receives location data from satellites (and sometimes roadside beacons for traffic data) to provide the onscreen journey/travel information. The driver can select destinations by address or landmark and the system will calculate a route based on criteria set by the user.
GPS stands for global positioning system, which uses a network of satellites to pinpoint the exact location of the car. This location data is used by the sat nav computer to calculate optimum journey routes factoring in drivers choice along with other factors such as traffic data. GPS signal is received via either a hidden or roof mounted antennae.

A sat nav system can often be retro fitted to a car that was not factory installed. Also components such as GPS receivers and screens can be replaced if they become faulty.