Is That You in Aisle 6?(global positioning system for use in cities)(Brief Article)

The interior stairwell in most office buildings is a no man's land, intended only for escaping fires. But for Michael Kim, it provides the ideal setting to show off his new product to visitors. Kim is the president of the South San Francisco start-up Enuvis. In the stairwell, he whips out an external antenna and laptop loaded with his company's algorithmic GPS software. (GPS stands for Global Positioning System, a network of 24 U.S. government satellites that can pinpoint your location anywhere on earth.) For the sake of comparison, Kim also brings a handheld GPS unit; it searches vainly for the satellite signals, but it can't locate them from inside the concrete corridor. Then Kim fires up the laptop. Within a minute, the antenna picks up eight of the satellites, and the laptop triangulates Kim's position within 50 meters (although it can't measure altitude). With such technology embedded into everything from car keys to badges worn by Alzheimer's patients, Kim says, 'Imagine a world where nothing and no one is lost.'

GPS is the other wireless network. Phone towers and antennas were put up by wireless carriers like AT&T and Sprint. But the 24 GPS satellites were launched by the Pentagon, back during the cold war. The government envisioned them as a military tool, helping to coordinate soldiers and equipment. The new world of high tech has changed that. The satellites today communicate with the 100,000 GPS units that are manufactured each month and embedded in everything from Hertz cars that give drivers en-route directions, to the PDA add-ons that allow golfers to track shots.

The most promising GPS application, however, has yet to be perfected: wireless phones. The U.S. Federal Communications Commission has mandated that by 2005 all handsets must include technology to allow emergency 911 operators to locate wireless calls, just as they can with calls from land-based phones. Most carriers are already behind schedule. One of their excuses is that GPS technology doesn't work well inside buildings. Obstructed locations like stairwells and 'urban canyons' ...