The Wi-Fi Positioning System
By Mark Frauenfelder, Wed Apr 28 16:30:00 GMT 2004

Who needs GPS when you've got Wi-Fi?


Google's biggest strength is its laziness. The company didn't want to work as hard as Yahoo did, which hired an army of busy librarians to comb through the Web, finding worthy sites to include in its directory. As the Web grew larger, Yahoo hired more and more librarians to create its directory. What a futile task!

The genius of Google was the way it used other people's Web sites to create its search-engine database. It harvested the collective editorial judgment of millions of amateur and professional Web site publishers, scooping up the links they published on their sites and using them to create a ranking system that works amazingly well.

Quarterscope, a Needham, Mass., company, reminds me of Google, not because it's a search-engine company (though search is an important component of Quarterscope’s technology), but because it, like Google, tapped into a previously unnoticed resource and used it in an unexpected and useful way.

Beyond GPS


The company has developed a Wi-Fi Positioning System (WPS) that can complement or, in certain cases, replace the traditional Global Positioning System (GPS). GPS works with devices that measure signals from dedicated satellites to triangulate the location of the device. GPS works great if you're in the great outdoors, but those expensive satellites are useless if the GPS device in your car, notebook or PDA isn't in a clear line of site with them. If you're indoors, or in a skyscraper-filled urban canyon, you're out of luck. But WPS uses the 5 million Wi-Fi hotspots that are scattered around the United States (which some esitmates say will grow to 10 million in the next 12 months) to pinpoint the location of any device that has a Wi-Fi chipset in it. As long as a Wi-Fi access points in range it’ll figure out where you are.

When Wi-Fi first came out, nobody thought that access points would be used like some kind of ground-based GPS system. Sure, several companies have developed indoor Wi-Fi location-based services (for museums and the like), but they are used in tightly controlled conditions. Quarterscope's WPS is the first outdoor Wi-Fi location detection system, and so far, like Google, it looks like the company is doing everything the right way.

Your Network Is Their Network


Quarterscope didn't have to pay for the network of millions of access points it uses. WPS is an all-software solution, which means it can be rapidly distributed and deployed. WPS takes advantage of the fact that almost all access points are configured to transmit their unique IDs whenever a Wi-Fi client sends out a scan request. Quarterscope exploits this capability (which doesn't drain the resources or compromise the security of access points) by combining it with the data collected by wardrivers, who use GPS systems and laptops to discover and map out access points in towns and cities. Once installed on a laptop or mobile device, the WPS software measures the time it takes for signals from nearby access points to return a scan request, and then uses triangulation to pinpoint the location. Quarterscope says it can locate a device to within 20 feet, and that improvements in the coming months will allow for even better positioning. The company hopes to launch the product commercially later this year, and plans to charge a monthly subscription fee to use the service. It says it'll have 90% coverage throughout the top 25 cities in the US.

Let Wi-Fi Show You The Way


Because WPS is interoperable with any application that can use GPS, it can be put to use right away in applications such as Microsoft Streets and Trips and Delorme Street Atlas. Quarterscope is also working on several in-house applications. One, called, WhereIsIt, will give you directions to the nearest gas station, ATM, hotel or restaurant. Another application provides a more general local search for different kinds of businesses and attractions. It can also add a location stamp to digital photos and documents. One intriguing application for WPS is a "LoJack" for laptops. (Notebook theft is a big problem -- 1.6 million were stolen in the US in the last three years, and only three percent were recovered.) WPS could be used to quietly send e-mail with your laptop's coordinates to a special address. If the laptop is ever stolen, you can find out where it is and track it down.

Recently, Quarterscope made a deal with another Massachusetts company, uLocate, to offer a service that allows subscribers to track the whereabouts of family members and employees, map their routes, review the speed and mileage of the cars they drive and "be notified when individuals arrive and depart from specified locations." Sounds useful for snoopy parents and employers. I'm just glad this wasn’t around when I was in high school.