Whilst many drivers still use their cell phone GPS its widely accepted that an in-dash unit is a much better option to help you with your navigation. Not only does an in dash GPS units help you with your navigation, but they also have a whole host of other features that can help you with your driving.
With any In-Dash GPS unit the first thing you need to look at is the unit ability to provide navigation. How in-depth are the maps and what navigation software does the unit come with. There is no point in having a great looking GPS unit if it cannot actually provide you with navigation. Most will feature a turn-by-turn navigation with audio instructions and well as navigation instructions on the screen. A GPS unit will work by using a combination of satellites to pin-point your location and then calculate the shortest route between two locations. Obviously having a fast processor speed helps this and also means that re-calculations work quickly if you make a mistake.
Good Maps and navigation make a GPS unit work well, but again there is no point in having a great Navigation software if you cannot see to the GPS unit. Old portable GPS units were so small that actually you could not see the information on the map. In-built GPS units mean that you can have a much larger GPS unit and therefore easily see your screen. Screen size can easily range from 5-Inches to 7 or 8-Inchs however you need to make sure that your in-dash unit will actually fit into your vehicle especially on older models where the vehicles simply do not have the space on the dashboard to fit your 7-Inch screen. We would highly recommend that you check with the company that your GPS unit will actually fit into your Car before you buy it.
Beyond the basic functions you then need to look at the extra functions for navigation and for entertainment. Navigation features could include, Voice Command, Voice Control, Turn-By-Turn Direction, Active Lane Guidance, over-head views, Map Updates and Traffic Alerts, whilst entertainment Functions could include bluetooth for hands free calling, iPod/iPhone connectivity to play your music, SDcards for extra storage, DVD players and CD players.