Kevin starts to play a video of last week's sales conference on the plasma screen in his office. Then, tablet in hand, he walks into the employee lounge to refill his coffee. As he moves into the lounge, the video turns off in his office and streams directly to his tablet screen. A remark made by one of the conference presenters reminds him that he has to update the Perkins file, which he left in his car.

As Kevin walks out the front door of the building, the video stream stops, and the tablet displays a dialogue saying that he is now outside of the allowed access area. His tablet still has a strong radio signal, but because the network is aware of his location, it can restrict his access.

Location-based access control is just one of many applications that will be made possible by technology now in development at Intel Research. In the Precision Location project, Intel researchers are developing technology that will retain the advantages of GPS while overcoming its key deficiencies.

The Challenge: Global Positioning System (GPS) technology is widely used for location-dependent applications, such as navigating outdoors and providing emergency (E911) services. However, this technology has some important limitations: GPS receivers typically do not work indoors or in "urban canyons" where high-rise buildings obstruct the line between the GPS satellite and receiver. In addition, there are a number of applications, such as inventory tracking, that require greater accuracy than a typical GPS receiver can provide, but only require this accuracy in a small local region.

The Solution: In the Precision Location project at Intel Research, researchers are developing high-precision location technology that will deliver the advantages of GPS while overcoming its key deficiencies. The new technology will work indoors as well as outdoors. A key goal is to develop technology that is accurate to within one meter.

Researchers have developed a prototype Precision Location system that consists of WLAN (wireless local area network) laptop computers and fixed access points (APs). The laptop communicates with each AP, to determine its distance from the AP using a Time-Of-Arrival (TOA) technique developed by Intel. The laptop also knows the location of every AP. The laptop, knowing its distance from any two APs, and knowing their location, can triangulate its own position. This position can then be utilized at the laptop or transmitted back to the network for infrastructure-based applications. Using this technique, it is possible to achieve highly accurate location information.

Potential Impact: When integrated into consumer electronic devices, high-precision, WLAN-based location technology could be an ideal complement to GPS location capabilities. The technology could be used in a variety of potential applications, such as indoor navigation, equipment tracking in real time (imagine a physician in a hospital who is searching for the nearest defibrillator), and location-based security applications. The technology is designed to maintain privacy; users control who has access to their location information.