Google Maps For Mobile Now Knows Your Location

Thursday, November 29th, 2007
by George Appiah

There’s never been a greater need for those devices we carry around to be location-aware. Location information not only helps us determine where we are, but location-aware mobile services also use this information to make mobile mapping and search faster and more convenient.

But the most common source of location information to date, which is GPS technology, is only supported on some of the bleeding edge mobile devices. In fact, fewer than 15 percent of the mobile phones to be sold in 2007 are expected to support GPS.

Now Google to the rescue! The latest update to Google Maps for mobile comes with a new technology they’re calling My Location, which enables users who don’t have GPS-enabled mobile phones to get location information.

But even for those gadgeteers with GPS-enabled devices, the My Location technology actually complements the GPS technology they already have, as it delivers a location estimate faster than GPS, provides coverage inside buildings (where GPS signals can be unreliable), and doesn’t drain phone batteries as quickly as GPS.

How Does It Work?

The video embeded below shows the simple magic Google uses to determine your location. In a nutshell, the My Location technology takes information broadcast from cellphone operators’ towers (Cell IDs) and sifts it through Google’s triangulation algorithms to approximate a user’s current location on the map.

But is it accurate? That’s the question. Now I don’t live in the US or any other country where Google has any siginificant geo-data, and I can only speculate from the technology angle.

Triangulation uses the Signal TOA (time of arrival), to estimate distances. In environments such as the inner city, with lots of structures, the signal bounces off here and there, which causes multipath effect, and this degrades accuracy - significantly.

In open areas free from reflected signal paths, TOA systems can be as accurate as GPS, depending on how the system is architected.

But, if your phone doesn’t have GPS, this service is surely better than nothing. Go download Google Maps for mobile with My Location, here »» www.google.com/mobile/gmm/index.html.