Global Positioning by Cellphone

THE man in the Verizon Wireless commercials wearing thick-rimmed glasses may be constantly asking, “Can you hear me now?” But the most commonly asked question over mobile phones might actually be, “Where are you now?”.
The combination of global positioning systems and cellphones may make that question moot. Cellphone carriers are now mandated by the Federal Communications Commission to provide location information for 911 emergency use. Many now have G.P.S. chips that can pinpoint the phone’s location to within a few feet, though others rely on triangulation, a technology that approximates location based on proximity to cellphone towers.
Even some phones without G.P.S. can help you navigate. The iPhone from Apple, for example, cannot precisely locate you or track you as you drive. But its Google Maps feature can be used to plan a route by entering a start address and a destination. It displays directions or a map.
But as more phones come equipped with a small and relatively inexpensive G.P.S. microchip, the technology is being used for all sorts of location services that the carriers and other companies offer for additional fees. The Disney Family Locator service on a Disney-branded mobile phone uses G.P.S. to track a child’s whereabouts. Parents buy special child and parent phones. The child’s phone is programmed to beam locations to the parent’s phone, which has the ability to display and map the approximate street address where the child is at any given time.
Verizon’s child locater, called Chaperone, adds a “geofencing” service that allows a parents to define an area — such as a school or baby sitter’s house — where the child is permitted. The parents receive an alert on their handset when the child’s cellphone enters or leaves the zone.
The G.P.S. phones have adult applications, too. Wherify Wireless offers a line of G.P.S.-enabled phones to track elderly relatives or employees. People doing the tracking can locate the trackees through a Web or cellphone interface or by calling the company’s toll-free number and providing the operator with a password.
The drawback to turning a cellphone into a G.P.S. device is that cellphone screens are generally smaller than stand-alone G.P.S. units and a regular cellphone keypad is not ideal for typing in a destination address. On some phones, you can get knocked out of G.P.S. mode if a call comes in. That can be annoying, especially if you need to take the call to confirm where you’re going or when you’ll get there.
A G.P.S. phone enables many other services. Certain phones using the Sprint/Nextel and Verizon networks can use Bones in Motion’s BiM Active application to track your speed, location, elevation and calories burned while walking, running or cycling. You can view your statistics and a map of your route on the phone or a Web page.
Most G.P.S. navigation systems for cars only receive location information, but Dash Navigation, a Silicon Valley start-up, is now testing its Dash Express, which instead of adding G.P.S. to a cellphone adds a cellphone signal to a G.P.S. unit. The cellular radio transmits information both ways between the car and Dash’s servers. Every Dash unit continuously transmits its location and speed so, once there are a sufficient number of systems deployed to create a network effect, the company can determine the traffic flow on any road where Dash users are driving, including surface streets.
Navigation systems will not only route you around traffic, but take you to restaurants it thinks you will like. The technology for this already exists, but, says, Mr. Williams, “most people won’t use it until they’re confident that it will work properly almost all the time.”