GPS, meet WPS. Mapping the next step

For the past few years, a company you likely haven't heard of has had hundreds of people all over the place, quietly seeking out and marking the location of Wi-Fi hot spots as a means of taking personal navigation one step, or several steps, further. Maybe even an entire walk.

See, as good as GPS is, the technology has its limitations. One restriction is that in urban areas—as likely a place as any for visitors to want navigational help—tall buildings can interfere with signals, sometimes rendering the devices useless. Pedestrians need navigation that stays with them every step, or bus ride, of the way. They tend to wander in and out of buildings, use public transportation, and generally place more demands on a nav system than say, a car cruising all day on the interstate.

Enter Skyhook Wireless. By mapping out all those Wi-Fi hotspots, Skyhook offers another way to let people know where they are and guide them to where they want to be. They call it the Wi-Fi Positioning System, or WPS. The way WPS works is by determining the number of hot spots within range of a user's device, usually five or so according to their Web site. They can then determine the location of that user and help them navigate from there, indoors or out. The downside is, the Web site also says Skyhook can only narrow that user's location to within 20 meters, so don't expect pinpoint directions to the rest room when you're in a rush.

In fairness to Skyhook, tracking and navigating for a user indoors at the pace of a walk is harder than doing the same for somebody barreling down the interstate. And GPS units have the advantage of combining location data with map data, while measuring strides from the local pharmacy to the grocery store is probably less common.

Attention iPhone users: you're already using Skyhook's WPS. (If you use the iPhone mapping, let us know what you think in the comments below.) As of this writing, iPhone doesn't offer GPS.

A Skyhook spokesman said the company doesn't see their product as an alternative to GPS, but as more of an enhancement, something to add to PND devices that will add to their capability and be transparent to the user – GPS on the road, WPS when inside. They also say they see a social networking application, where users can more precisely locate one another as being a popular selling feature. And hey, think of other uses. Mall walkers rejoice.

Skyhook says to expect their WPS to be included with navigation devices from major suppliers within the next year, and that they've already located some 33 million hotspots in North America. And according to that same company spokesman, they're adding 100,000 every day.

—Jim Travers

For more information on portable GPS navigation systems, see our Ratings and buying advice and watch our video guide. Discuss GPS devices in the forums.