A GPS navigation unit that is built into the dashboard of a vehicle. Aftermarket units that replace the factory head unit may include AM/FM/HD and satellite radio as well as hands-free cellular.

"But there’s still a place for phone-based navigation apps and dash-mounted GPS units, especially if you drive an older car ...

Sure, your phone screen can provide a decent GPS map while ... display on your dash. With wireless connectivity via Bluetooth, you can pair your smartphone and access apps, navigation maps ...