Skyhook Blends GPS, Cellular into Wi-Fi Location-Finding System

6/30/08Follow @wroush

Imagine if Microsoft admitted that people might like to run the Macintosh operating system on their Windows computers. Or if Apple made it possible to run Windows alongside Mac OS X. (Oh wait, they already did that.) Well, that’s a little bit like what Boston’s Skyhook Wireless is announcing this week.

After spending five years perfecting its Wi-Fi Positioning System (WPS), which calculates a device’s position by comparing incoming Wi-Fi signals to a huge database of the known positions of Wi-Fi networks in urban areas, the company said today that it’s bringing out a new “hybrid” positioning system that relies on location data from multiple sources, not just Wi-Fi. The revised system, called XPS 2.0, combines data from GPS satellites and cellular networks with Wi-Fi signals to get the most accurate location fix possible in any situation.

The technology—which is being integrated into wireless chipsets for next-generation mobile phones and other devices, including, possibly, the iPhone 3G—is designed to cope with the basic physical limitations of both GPS and WPS. To triangulate an accurate position via GPS, devices need a fairly clear line-of-sight to three or four satellites in the sky, which means they don’t work well in urban canyons, and they don’t work at all indoors. (On top of that, it can take up to 60 seconds to find four GPS satellites, which is a big battery-drainer.) Wi-Fi signals, by contrast, are plentiful inside homes and office and apartment buildings—but they only travel about 100 yards from base stations, and aren’t widely present outside cities.

“We believe that in order for location [services] to be widely adopted on mass market devices like phones, it has to work to the level that consumers expect, whether they are at home or at work, indoors or outdoors, in Manhattan or Montana,” says Skyhook CEO Ted Morgan. “We can’t keep sending mixed messages to consumers like, ‘Go outside and stand on the corner if you want to find the nearest coffeeshop,’ or ‘Make sure you’re near a building with Wi-Fi to get a fix.’ It has to work everywhere, and no one system can provide that.”

It’s a pragmatic step for a company where executives have spent years arguing that GPS just isn’t up to snuff as a location-finding system for consumer devices. From Morgan’s point of view, the company has made its point, and it’s time to figure out how to make the various location options work together. “We’ve spent the last five years focused on Wi-Fi,” he says. “That is the unique piece we bring, and we wanted to make sure that we established Wi-Fi positioning as a major part of location. But ultimately, we recognize that it has to be a combination of all these radios to get the best position.”

Morgan says Skyhook engineers have been working for the last nine to 12 months on software that doesn’t simply switch between GPS, WPS, and cellular signals based on their availability, like previous systems, but grabs all three at once to produce a single hybrid estimation of a device’s location. It turns out that being able to pick up just two GPS satellites, for example, can boost the accuracy of a WPS fix significantly.

“In these difficult urban environments, where 30 to 40 percent of the time you can’t get a good GPS fix, you can always get at least two satellites,” explains Morgan. “Those two signals allow us to refine the estimate that we’re able to make with Wi-Fi positioning, and in only two or three seconds—so not only is the user experience better than with GPS alone, but you are hitting the battery much less.” (XPS is also far more power-efficient than so-called “Assisted GPS,” which relies on a combination of cellular signals and GPS signals and can take up to 30 seconds to obtain a fix, Morgan says.)

To build its own database of signal strength measurements around cell towers, the company has added equipment that sniffs cellular signals to the trucks that already criss-cross the nation’s urban areas documenting the locations of Wi-Fi networks. And at the same time as its XPS 2.0 announcement, Skyhook said that it’s working with CSR, a Cambridge, England, chipmaker known as the world’s leading provider of Bluetooth chipsets, to put WPS into CSR’s Wi-Fi and GPS chips. Skyhook already has deals with major location-sensor makers such as San Jose, CA-based SiRF Technology, so the upshot of the CSR deal is that a larger group of device makers will have access to hybrid positioning technologies.

“Everyone is rapidly coming to the conclusion that hybrid positioning is the way to meet consumer demands,” says Morgan. “It just so happens that we’re really the only commercial provider of a Wi-Fi positioning system like this, which is why you see all the chipset manufacturers lining up with us. The device makers don’t want to deal with more than one vendor.”

But whether “all device makers” still includes Apple is a little vague. Skyhook is probably most famous for supplying the Wi-Fi portion of the positioning technology that Apple built into the first-generation iPhone in a major software update in January. I asked Morgan whether the hybrid positioning system that Apple says will be part of the iPhone 3G (available July 11) is, in fact, XPS. “I can’t really get into a lot of details about how Apple uses our stuff,” he replied. “They are fairly protective of information about their products. I can tell you that they have access to the full range of our technology and that Skyhook is a big part of the 3G version of the iPhone.”

Wade Roush is a contributing editor at Xconomy. Follow @wroush

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