HOW MOBILE PHONE GPS NAVIGATION WORKS 

Similar to GPS tracking devices and also in-car Global Positioning System navigation systems, GPS-enabled phones let you view and listen to turn-by-turn directions via your handset, whilst also allowing cellphone GPS tracking through the use of tracking software. Additionally voice-enabled GPS locators can act primarily as a GPS tracking device but also contain basic cellphone GPS functionality such as voice communication and 2 way SMS messaging.

 E 911 

Coming soon is E911. E(nhanced) 911 is a program mandated by the U. S. FCC (Federal Communications Commission) and it is driving the development of gps cellphones. It mandates for the location of any cell phone that dials 911 and that by using GPS, the cellphone can be determined to within 50 to 100 meters. That means cell phone manufacturers need to incorporate a GPS receiver in virtually every cell phone. Outside of E911 this means that the combination of a cell phone and GPS enables 3 additional uses: 1) driving directions in your automobile, 2) the ability to use a cell phone as a handheld GPS for out-of-car purposes and 3) the tracking of the cellphone by GPS.

 GPS CELLPHONE SERVICES 

You can subscribe to a GPS navigation service through Nextel. Nextel offers two of them: Televigation's TeleNav and Motorola's ViaMoto. Using the GPS and Nextel's cellphone network, TeleNav and ViaMoto send driving directions--complete with street names and mileage reports--directly to your Nextel phone. The most impressive part is the services' rerouting capabilities. If you miss a street or make a wrong turn, TeleNav and ViaMoto automatically detect that you're off the route and calculate a new route to put you back on track.

TeleNav and ViaMoto also offer location-based services. Think of them as yellow pages with driving directions: Just choose the category you're looking for (such as hotels, restaurants, or movie theaters), and the service does the rest. It determines your location and downloads onto your phone search results that include business listings typically within 5 to 10 meters of your location. Once you make your choice, you can get driving directions.

Bear in mind that in areas without Nextel network coverage, the GPS navigation tools work. The GPS functionality is currently dependent on a network signal; analog roaming won't do the trick. TeleNav and ViaMoto use servers that work with Nextel's network to transfer information.