Automotive navigation systems utilize GPS (Global Positioning System) information to locate the users whereabouts on a road and then determine from the units database to map out the location of the car. Using road database, the unit can give directions to other locations along roads also in its databases.
Many units also incorporate dead reckoning which uses the distance between sensors, often cellular phone towers, calibrating signal loss to determine the speed and direction of a moving vehicle.

Earlier versions developed by Alpine in partnership with Honda, as well as Mitsubishi and Pioneer claim to have a model available as early as 1990. However, Magellan, a GPS system manufacturer, claims have created the first GPS based vehicle navigation system in the U.S. in 1995.

Since then, handheld GPS has become more popular as the customer can pinpoint their location not just when in the car, but anywhere they may be located. Although many manufacturers allow the unit to do double duty, only outdoors minded units are designed to handle the elements, are water resistant and have better shock prevention measures taken. Handheld GPS units are also meant to be lightweight and easy to hold in one hand whereas many auto based units needed to be installed with automotive wiring and mounted in dash.

Many units now will allow you to see street names and number or even the house numbers as they correspond with geographic coordinates. Now, you can actually find your desired location by street address along with points of interest such as restaurant, government office, or any other criteria you state. The contents of the database can either be loaded in the system or, using WiFi communications, the device can connect with the internet to get the most up to date mapping information. Formats are almost uniformly proprietary; there is no industry standard for satellite navigation maps although consumer groups have called for more uniformity similar to cellular networks and computer operating systems.

Another option being used for in car navigation is using Bluetooth accessories with a laptop or a PDA. Some manufacturers of PDAs come with an integrated GPS antenna but most can accept an accessory reciever. Since a laptop has a much larger screen than an auto GPS system, and has far more hard drive storage for maps, they are capable of a more comprehensive database. Granted they are not easily installed in your car, they do work best if you have a software with audible directions.

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