Installation of the 'bolt on' kit should take two hours and the digital mapping will initially cover the area inside the M25 and all towns and interconnecting routes in Kent, Surrey and East and West Sussex. Customers will automatically receive an updated CD twice a year.

Initial subscription is £125 plus VAT with the cost of a single CD pitched at £100 plus VAT. CDs of other countries are available for £35 plus VAT each. Maps are already available for Germany, France, Benelux and a combined map for Northern and Central Italy, Austria and Switzerland.

Carin works by providing a first rough estimation of the car's position using transmissions from American defence satellites. Systems within the car improve the accuracy from 100 metres down to less than 10 metres. The driver is guided by both maps and 'rally-style' tulip arrows on the screen and a female voice.