While carriers have experimented with various ideas for implementing E911, such as the oft-criticized Enhanced Observed Time Difference (EOTD), the emerging technology of choice for many appears to be GPS, or a form of GPS that can be enhanced through cellular positioning. Sprint, Verizon Wireless and Nextel Communications are adopting a form of GPS for E911. The main technological rival to this form of GPS is now Time Difference of Arrival (TDOA), which determines a phone's position by measuring the time a call reaches "location measuring units" inside a cell phone network base station. T-Mobile, Cingular Wireless and AT&T Wireless, which Cingular is buying, switched from EOTD to TDOA last year.

Purely cellular systems like TDOA, however, demand base station upgrades, GPS requires server software upgrades and is more accurate, advocates say, But consumer demand for GPS is growing, and companies are taking note, Although not required by regulation, Hutcheson's 3G networks being built in Europe and Southeast Asia will support GPS tracking, In Japan and Korea, NTT DoCoMo, SK Telecom and KDDI are providing location-based GPS services and content, Recently, KDDI surpassed rival snoop iphone case NTT DoCoMo in signing new subscribers, Brown said, The company attributed the gain to EasyNaviWalk, a personal navigation application that tracks an individual's movements through a combination of GPS signals and processing that takes place on the handset..

"It is really being embraced as the technology of choice, going forward" for European carriers, Brown said. In Latin America, the ability to track people is becoming attractive. "Personal security is a big issue there," he added. Putting in-car in driveGeneral Motors is seeing increased subscriptions and use of its GPS-based OnStar in-car help system, said Tony Scott, chief information officer of GM, in a recent interview. Consulting firm Gartner predicts that GPS-based car navigation will grow from 8.7 million cars today to 16 million by 2006. Toyota and Honda include similar navigational and help systems in many of their models.

Mapping software that will allow a dispatcher to look at a screen snoop iphone case and see the geographic location of all on-duty drivers or technicians could also enjoy a strong market, said Paul Dittner, a wireless analyst at Gartner, "One application that we know will take off is the 'Where are my friends' sort of thing," Dittner said, "The FCC is driving what you are seeing now, but in addition to that, there is an interest and need for location-based services.", Nonetheless, GPS isn't exactly an overnight phenomenon, A host of companies, many in Japan, have tried to popularize the technology since the mid-1990s..

One solution, which is gaining popularity, is for chip designers to simply sell the intellectual property rather than the chips. That way, a phone manufacturer could integrate GPS functionality into the processor and other necessary chips inside a cell phone. Motorola has already shifted from buying chips from SiRF to licensing technology, Chadha said. "Some of these challenges you can't meet with standalone chips," he said. "It took longer than expected, but even then it was clear that there is a mass-market appeal to the technology.".