An update to Google’s Maps for Mobile service, which is currently available as a free download to compatible cellphones and has formed a flagship part of most Android demos to-date, adds the company’s own version of Assisted-GPS that uses both cell towers and other users handsets to triangulate your position.  In a product demo with the NY Times, division manager Steve Lee revealed that the software relies on unsecured GPS hardware in cellphones and other devices to identify and accurately locate individual cell towers:

“Google figures out which cell towers are where by secretly enlisting the help of a million of its mobile maps users who happen to have phones with built-in GPS devices that are not locked by the carriers (that means no one who uses Verizon). These phones have been reporting to Google where they are, based on the GPS data and what cell tower they are connected to” Saul Hansell, NY Times

Lee is dismissive of the potential privacy concerns, and indeed the company’s Privacy Policy gives Google express permission to use the data that is recorded from an individual’s handset to augment functionality such as Assisted-GPS:

“If you use location-based products and services, such as Google Maps for mobile, you may be sending us location information. This information may reveal your actual location, such as GPS data, or it may not, such as when you submit a partial address to look at a map of the area … We use the information for support, to develop new features, and to improve the overall quality of Google’s products and services” Google Mobile Privacy Policy

While the information on each user GPS-identified is not linked with any personal details (such as mobile number), nonetheless the system does match together location and any related search queries: 

“The payoff for Google from building out its mapping service is to get people to conduct searches from their cellphones. This is a nice feature. Push a button on the map software, type “Starbucks” and it will display a map of the closest source of a latte fix, based on the cell tower or GPS data. The catch, is that this query, with your location, is entered in Google’s log files along with your phone’s unique ID” Saul Hansell, NY Times

Ironically, despite the upgrade Hansell found the service on a non-GPS cellphone consistently misjudged where he was located (Google’s margin for error is quoted as usually being between 500 and 2,000 feet).  Given the likelihood that Maps for Mobile will feature in any production Android handset, though, users may need to closely examine the privacy policies and terms & conditions before assuming that their cellphone isn’t reporting in their current position.