Automotive navigation system

An automotive navigation system is part of the automobile controls or a third party add-on used to find direction in an automobile. It typically uses a satellite navigation device to get its position data which is then correlated to a position on a road. When directions are needed routing can be calculated. On the fly traffic information can be used to adjust the route.

Dead reckoning using distance data from sensors attached to the drivetrain, a gyroscope and an accelerometer can be used for greater reliability, as GPS signal loss and/or multipath can occur due to urban canyons or tunnels.

Automotive navigation systems represent a convergence of a number of diverse technologies many of which have been available for many years, but were too costly or inaccessible. Limitations such as batteries, display, and processing power had to be overcome before the product became commercially viable.Etak made an early system that used map-matching to improve on dead reckoning instrumentation. Digital map information was stored on standard cassette tapes.

The road database is a vector map. Street names or numbers and house numbers are encoded as geographic coordinates so that the user can find some desired destination by street address (see map database management).

Points of interest (waypoints) are stored with their geographic coordinates. Formats are almost uniformly proprietary; there is no industry standard for satellite navigation maps, although some companies are trying to address this with SDAL and NDS.

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