Market for car navigation devices expected to explode

Although Brandweek says fewer than a million people in the United States use GPS devices, sales increased about 153 percent in 2005. Thales Navigation, which makes Magellan GPS products, predicts the global market for navigation devices will reach $5.4 billion by 2008. Carmakers and navigation technology companies are catching on to this trend and offering more choices for car navigation systems.

Virtually all carmakers today offer factory-installed, in-dash navigation systems in at least some of their models.

Factory-installed in-dash navigation systems feature monitors that usually sit level in the dashboard. They cost roughly $2,000, plus installation fees. Dealer-installed ones have monitors that either sit level or flip out and up, depending on the size of the dash opening, and can cost from $1,000 to $2,000, plus installation fees.

In-dash systems often consist of a CD stereo with a built-in monitor that ranges from 6 1/2 to 7 inches. Most in-dash systems require an external GPS antenna, can play DVDs, and transmit the system's voice prompts through the stereo.

For the commitment-wary, plug-and-play navigation systems that can mount onto the windshield or dash are available. They often come equipped with built-in speakers and antennas. They are typically portable, such as TomTom or Garmin models.

Plug-and-play models commonly feature more points of interest, and the monitors range from 3 1/2 to 7 inches. These models can cost from $250 to $1,600, depending on the size and sophistication of the unit.

Whether an in-dash or plug-and-play model is right for you will depend in large part on how often you plan to use it. The system should fit the layout of your car so it doesn't obstruct air vents, the passenger seat, or your view of the road .

More complex models will take longer to install, and manufacturers warn they will void your warranty if an in-dash navigation system is installed by a consumer or unauthorized dealer.

The most important things to look for in a navigation system are accuracy and the speed and ease of use. Your system should provide multiple ways of getting to your destination, vocal and graphic directions, and a strong GPS satellite signal reception. Text-to-speech technology eases travel by giving specific street names rather than a general directive. Be sure you're comfortable with operating the menu via touch-screen controls, exterior buttons, or a remote control, and make sure the system won't distract you.

Technological advances are allowing companies to expand the range of navigation system features. Navman introduced a camera that stores GPS information in image files you can share online with friends. TomTom now offers ``Buddies," a system that tracks the location of friends and family who are also logged in to the TomTom system. You can then share interesting sites with each other, or use the available hiding feature to conceal your location.

Google, Volkswagen, and nVidia, a graphic-chip maker, are working on a photo-realistic 3D Google Earth navigation system. TomTom now offers downloadable celebrity voices, along with downloadable logos that show the location of favorite vendors . Garmin provides an optional database that maps popular retailers and offers users discounts.