Wi-Fi location system is better than GPS, says start-up

A Boston, Massachusetts-based start-up says it has developed software that uses Wi-Fi signals to pinpoint locations better than satellite-based global positioning systems can.

On Monday Skyhook Wireless announced the commercial availability of its Wi-Fi Positioning System, or WPS. The software, which is now available to application developers and device manufacturers, uses 802.11 radio signals emitted from wireless routers to determine the precise location of any Wi-Fi enabled device, whether it be a PC, laptop, PDA, Tablet PC, smart phone or RFID tag.

The way it works is that the company has compiled a database of every wireless access point in a given a city. It did this by having people literally drive the streets "listening" for 802.11 signals. Using the unique identifier of the wireless router, it notes in the database where the access point is located.

When a mobile user running the Skyhook client pops up in a neighbourhood, the software scans for access points. It then calculates a user's location by selecting several signals and comparing them to the reference database. The more densely populated the area is with Wi-Fi signals, the more accurate the software is at locating the device.

Ted Morgan, CEO of Skyhook said the location system is more accurate than global positioning systems that use satellites to find locations.

"GPS was designed by the military for guiding missiles," he said. "It performs poorly in urban areas where buildings block the view of satellites, and it doesn't provide any coverage inside of buildings."

Morgan adds that GPS typically only locates things within a few hundred meters, whereas the Wi-Fi location system can get within 20 to 40 meters of an object. And because Wi-Fi routers are often deployed closer together in cities than mobile phone masts are, it can also be more accurate than cellular-based location systems, he added.

Skyhook's software could be used for a whole slew of applications. For one, it could be useful in helping voice over IP providers comply with a federal mandate to have location based services for E911.Craig Mathias, a principal at Farpoint Group, a consultancy specialising in wireless and mobile technologies, said it would be simple to build a device running the Skyhook software that attaches to VoIP phone adapters to provide location information for E911.

There are other applications as well. Morgan envisions the software being used to provide more accurate driving directions within cities. Hardware manufacturers could make inexpensive devices that plug into cars to provide directions or to help locate restaurants and other businesses.

The technology could also be used to help track stolen equipment such as laptops. And if coupled with RFID technology, it could be used to help locate merchandise that's being transported.

Neil Strother, a senior analyst at In-Stat, said: "It seems like a pretty good concept. Wi-Fi signals offer a lot denser coverage in some places than cell towers. And GPS is great if you're on a boat or somewhere like that but in tighter urban areas GPS location systems can be kind of goofy."

But there are potential drawbacks. The software is dependent on dense deployment of Wi-Fi. So the technology is inherently better suited for urban areas than sparsely populated rural areas where Wi-Fi is not deployed at all or where access points are deployed too far apart from each other.

Also, some critics point out that Wi-Fi routers do not necessarily stay in one position forever like satellites or mobile phone masts do. People often move and take their Wi-Fi routers with them. Morgan said that the software is able to detect when a Wi-Fi access point has been moved and that it makes note of the change in the database. He also said that once a year the company plans to update the database by taking to the streets again to find new Wi-Fi signals.

Currently, Skyhook has mapped 25 major cities in the United States, including Boston, Chicago, Los Angeles, New York and San Francisco. The company plans to increase that coverage in the US to 100 cities by the end of the year. It will also start mapping Wi-Fi signals in certain cities in Europe later this year.

Marguerite Reardon writes for CNET News.com