Automobile navigation systems have been with us for a while now, and every year it seems that new features are bolted on to the various systems. All of them are based on GPS, or global positioning systems. Simply put, the device interacts with a satellite that establishes, with varying degrees of accuracy, exactly where you are. Depending on the system, it uses DVD for backup information or other software that has specific geographic information on it to determine your location, right down to the street corner.

There are a number of GPS systems that are sold as individual hand-held devices, and there are even some phones with the feature built in. But for automobiles, virtually every manufacturer now installs them as an option. Many of them are provided by major electronic manufacturers as OEM items.

A GPS position - that is, your spot on the planet - isn't much good unless the device that is providing that information can put it in a framework. That's where some of these systems are better than others, and where the breakdowns often occur. A typical automotive GPS will have a small dash-mounted screen that shows your position on a map. It's critical that whatever source is providing that map be up to date - perhaps the most common objection heard from drivers with GPS systems supported by CDs or DVDs.

Many of the systems today allow you to input your departure point and/or destination and will then provide you with driving instructions along the way. They will also provide you with information about gas stops and hotels along the route, along with information about points of interest across the country. Generally, the newer versions of this technology manage to stay up to date through downloads. One of the difficulties, however, can be a decision to detour. That may mean a major reprogramming headache and for many cars, the entire system may need to be turned off.

The General Motors OnStar system has been in operation for several years and has provided navigation assistance along with other remote features including contact with an OnStar employee in times of emergency. Their latest navigation methodology provides "turn-by-turn" instructions taking you through your course from departure to arrival.

In this case, the specifics on directions are downloaded from the OnStar service. A driver pushes the OnStar button, and then tells an OnStar operator where he or she is going. The appropriate directional information is downloaded in a matter of moments to your car's GPS device. The directions are displayed in text on the dashboard monitor, and there is also a voice prompting you to make the correct turns.

The problems? With this system, the OnStar operator needs to begin providing your programming with an address. So you'll need to know the street number of that Holiday Inn you're departing from. There are also occasions when the operator isn't going to find a site in the database, either because your information is incomplete or theirs is. If your plans change with the OnStar system, it will simply tell you that you've left the route until you once again contact the OnStar phone center and have them reroute your vehicle.

Pioneer Electronics has been among the principal providers on in-dash navigation systems and their new products will combine features of navigation, entertainment, and connectivity for maximum consumer appeal. Their navigation system has its route guidance information embedded in the unit and includes nearly 11 million points of interest, voice prompting and mapping. Their handheld version of this device includes entertainment features and wireless connectivity.