Google enables Location-aware Applications for 3rd Party Developers

Posted by Zhengrong Ji and Ravi Jain, Google mobile team

At Google we're very excited about the promise of location technology to drive innovation in the mobile industry. We of course use this location technology already in Google Maps for mobile with the My Location feature. However, we wanted 3rd party developers to also have access to the same location technology across multiple platforms. Gears for Windows Mobile and Android already contain location APIs and we expect to see an explosion of mobile applications that use location technology, particularly on the iPhone starting this month.

Some have wondered: How does it work?

Google Maps for mobile version 2.0 launched last November with a new feature called My Location. My Location enables users to pinpoint their approximate location on a map even if their phone doesn't have a GPS chip. My Location is now available in more than 200 countries and across many different platforms, including BlackBerry, Nokia Series 60, Apple iPhone/iPod Touch, Windows Mobile, and many Java phones. Here's a video that explains what it does. Since the launch, we've seen accelerated growth in the adoption of Google Maps for mobile and have received lots of enthusiastic user feedback on My Location.

We're happy to lift the covers and give you a peek into the inner workings of the Google location server, which powers the My Location feature.

Wireless phones can make and receive calls because they are connected over the air to a nearby cell tower. The phone knows the ID of the cell tower that it's currently using. If the phone has GPS, the Maps application on the phone sends the GPS coordinates along with the cell ID to the Google location server. Over millions of such updates, across multiple phones, carriers, and times, the server clusters the GPS updates corresponding to a particular cell ID to find their rough center. So when a phone without GPS needs its own location, the application on the phone queries the Google location server with the cell tower ID to translate that into a geographic location, i.e., lat/long coordinates. Nifty, huh? We think so.


We're working hard to further improve our location platform and making it more widely available. Stay tuned!