FRAMINGHAM, 5 FEBRUARY 2009 - Wednesday, Google released the real-time location tool Google Latitude and opened up a new world of location-based services (LBS) for both PC and mobile phone users.
Latitude enables you to track friends, family, employees and so on -- and vice-versa -- in real time. Whether this is a good thing (hey, you'll always know where your buddy is in the stadium parking lot ), or a preview of a corporate 1984 world where your boss can track your every move , will be determined by how we'll use the service. It's no surprise that at least one privacy group has already voiced security concerns over Latitude.
For now though, the questions most people have are about whether they can use Latitude and how it does its location voodoo.
Can I use Google Latitude?
According to Google, if you have any mobile device that supports Google Maps for Mobile v3.0 and above, you're probably good to go. These include Android-powered devices with Maps v3.0 and above; most color BlackBerry devices; most Windows Mobile 5.0 and above devices; and most Symbian S60 devices.
In the near future, you'll also be able to use Latitude on iPhone and iPod Touch with the Google Mobile App in the U.S., and on many Sony Ericsson devices. In addition, you can use Latitude today on a Linux, Mac or Windows PC by using the Latitude iGoogle gadget (you'll need a Google Account) and iGoogle, Google's personalized Web portal.
How do I get it?
Mobile users need to first have Google Maps 3.0 or above installed. After that, you can install Latitude. PC users can install the gadget by starting from the Google Latitude site.
I don't have a GPS (global positioning system) chip in my phone. Can I still use Latitude? You betcha. Latitude can use Wi-Fi access points; cell towers or GPS to work out your location.
How does Latitude do that?
Google is using technology from Skyhook Wireless Inc. in the Latitude service. According to Nick Brachet, Skyhook's CTO, the company's XPS hybrid positioning system is "a software-only location solution that allows any mobile device with Wi-Fi, GPS or a cellular radio to determine its position with an accuracy of 10 to 20 meters. What sets XPS apart is that it uses land-based Wi-Fi access points, GPS satellites and cellular towers to determine location information."
In other words, Skyhook's software can use any of the three kinds of signals -- Wi-Fi, 2G/3G/4G mobile or GPS satellite -- that a device can pick up to work out its location. By leveraging these wireless capabilities, Skyhook's software can combine positioning data from satellites, carrier assistance servers and Wi-Fi base stations to significantly speed up positioning, or TTFF (time to first fix). TTFF for some devices can be up to a minute, but the addition of Skyhook's XPS can reduce TTFF to a few seconds.
I thought you had to have GPS to work out your location. How does Google/Skyhook get around that?
The technique that Skyhook uses to work out your location is actually the same one that any GPS device uses: triangulation.
Here's how it works: When Latitude turns on, it automatically tries to reach any available GPS satellite, cell tower or Wi-Fi access point (AP). Once it establishes three or more links, it starts working out your location.
It does this essentially by figuring out, for example, that if you're two blocks from the cell tower at the church, and you're right under the Wi-Fi AP at the coffee shop, and you're at x distance from a GPS satellite, you must be at Buster's Coffee Shop. Typically, devices can use up to 24 reference points to work out your location.
Now, by itself your mobile device doesn't have the CPU horsepower to work that out. It takes the raw data and transmits it via a GSM, CDMA, or Wi-Fi link to an assistance server. This technique is called A-GPS (Assisted GPS). Your mobile device or computer works together with the server to plot out your location.
And this is the important part for Latitude: Since the assistance server has the results of the calculation, it's easy to share your position with anyone else who uses Latitude and has your permission to see your location.
How does the system know where Wi-Fi APs and cell towers are? Skyhook keeps a database of public Wi-Fi AP locations, and Google has a database of Wi-Fi AP and cell tower locations. Together, these tens of millions of fixed locations give Latitude the grid it needs to work out your location.
How accurate is Latitude?
It depends. If all you're working with is Wi-Fi APs, as would be the case with an iPod Touch or most PCs, it can only work out your location within about 200 meters. If you're using multiple cell towers, say you're in a city, you can get it down to a 100-meter circle. In the country, you may be as far out as 300 meters. And with GPS, you can lock down your location to a few meters. If you combine systems, you can be within GPS' accuracy range.
Many variables can interfere with your accuracy, however. Unfortunately, there are no hard and fast rules on determining how accurate Latitude or any other LBS application will be at any given location. For example, if you're inside a large building, you probably won't get a GPS signal. On the street, you may get the GPS, but you'll lose the Wi-Fi signals.
One way or the other, though, we're entering an age where you can always keep track of where you're at, who's near you, and what businesses are close-by. The flipside, of course, is that they can also track you.
Steven J. Vaughan-Nichols has been writing about technology and the business of technology since CP/M-80 was cutting-edge and 300bit/sec. was a fast Internet connection -- and we liked it! He can be reached at sjvn@vna1.com.
