The terrorist blast had destroyed the office building. Piles of glass and concrete littered most of a city block, the air was thick with dust, debris still smoldered. The police had no suspects but had already sent out an all-points alert. Then, when troopers pulled a van over for making a couple of risky lane changes, they found a pile of fertilizer sacks and an empty fuel-oil drum in the back. A duffel bag held a change of clothes, a small kit with a new razor and other toiletries, and a .45-caliber pistol. The truck had been stolen, and the driver wasn’t talking.
Within an hour, some 1000 km away, an FBI team walked into a Wal-Mart with pictures of the arrested man. One of the cashiers recognized the face. ”There were four of them,” she said. ”One of our regular customers said they were friends visiting from out of town—but that guy’s a loner. He lives out on County 15.”
This may sound like the start of a mediocre TV drama. But given recent events—and coming technical advances—it just might be a scenario pulled from tomorrow’s news. Here’s the rest of the story: a bit of microcircuitry called a radio frequency identification (RF-ID) tag was embedded within the package of razor blade cartridges in the suspect’s toiletry kit. The manufacturer inserted it into that package, and all others of its kind, to let retailers track inventory cheaply and conveniently. But because the tag carried a unique identifying code, the FBI could scan it, check it against a database, and then track down the store where the razor was purchased.
The future, in this case, is already here. This past January, the Gillette Co. (Boston) announced that it would purchase up to half a billion RF-ID tags to put on its Mach3 and Venus razors and razor blade packages. The tags, which contain chips that respond to an RF field from a scanner, are now being used in a test by Wal-Mart Stores Inc., by the UK-based grocery chain Tesco PLC, and most recently by Metro AG, Germany’s largest retailer, to determine whether the technology can streamline inventory management and save retailers billions of dollars a year in supply chain costs.
It’s not much of a stretch to imagine this relatively benign way of tracking goods being put to other, more dramatic uses. Indeed, RF-ID tags are only one example of a coming wave of wireless communications technologies that will be everywhere in the next year or two, merging location and time-related information.
The most spectacular of these will be large-scale systems that piggyback on cellular networks to locate any cellphone on the network—in other words, in the near future, your whereabouts won’t be a secret if you are carrying your cellphone. Other plans revolve around smaller-scale technology that will, for example, let you buy an item merely by pointing at it with your cellphone.
The commercialization of these technologies promises to make your life safer, easier, and more enjoyable by providing instant, personalized information. It might even save your life by helping rescue officials find you in an emergency, no matter where you are.
But these benefits will almost certainly cost you some privacy. In the case of the tagged razor blades, the loss will be small and incremental; with cellphone tracking, it could be substantial and potentially intrusive. So, in coming months, expect some clashes as watchdog groups, businesses, and governments try to find common ground and deliver the benefits of location tracking with the least possible intrusion.
The current push for location-based services in North America started in 1996, when the U.S. Federal Communications Commission (Washington, D.C.) passed its much-debated Enhanced 911 (E911) mandate. This rule, revised in 1999, requires wireless carriers to be able to locate, within 50 to 100 meters, any wireless phone calling 911, the U.S. nationwide emergency service number. The object is to let emergency operators pinpoint where a call comes from so that responders can find you if you don’t know your location, cannot speak properly, or get cut off. U.S. wireless operators currently have until December 2005 to comply with this proviso.
In the meantime, rollout of the capability has already begun in some places. Since late 2002, for instance, the entire Sprint PCS network has had an emergency locator capability. Another network, Cingular Wireless, has successfully tested a location technology in Wilmington, Del.
This location technology requires few modifications to cellphones. Location methods may, but often do not, make use of information from the Global Positioning System (GPS), the constellation of U.S. military satellites that are used to guide everything from bombs to ordinary passenger cars. Exactly how the location technology is implemented depends on the underlying cellphone network.
In Europe, the prevailing cellular standard is the Global System for Mobile Communication (GSM), which is also now taking root in the United States. For GSM networks, the location technology of choice is called Uplink Time Difference of Arrival. This technology depends on a form of triangulation: it requires at least three cellular base stations to receive a signal from the wireless handset, and then computes the location from the differences in arrival times of the three signals. Accuracy is best in urban areas of dense base-station coverage. The technique does not require that subscribers buy new handsets, and it does not affect network performance.
A drawback is that location measurement units costing as much as US $10 000 must be installed at each base station. The dominant cellular technology in the United States, time-division multiple-access (TDMA), also typically uses the Uplink Time Difference of Arrival method for determining location.
Meanwhile, code-division multiple-access (CDMA) networks, which is a spread-spectrum method of communications that is making inroads into TDMA, are turning toward a location technology called Assisted GPS, which, as its name suggests, makes use of the satellite network.