
Google released today a new version of
Google Maps for Mobile devices. Apart from some cosmetic changes and menu cleanup, the big splash is the
My Location feature which enables the software to derive your location using cell tower calculation also known as
trilateration.
Here's the explanation of such technology from
Wikipedia :
Trilateration is a method of determining the relative positions of objects using the geometry of triangles in a similar fashion as triangulation. Unlike triangulation, which uses angle measurements (together with at least one known distance) to calculate the subject's location, trilateration uses the known locations of two or more reference points, and the measured distance between the subject and each reference point. To accurately and uniquely determine the relative location of a point on a 2D plane using trilateration alone, generally at least 3 reference points are needed.
I've seen some web references that says this is now possible due to the earlier purchase of
Jaiku. However I do not think this is the case. The
Jaiku mobile softwarewas only recording the current cell id and associating a name to it and relaying that information to the server. This information is readily available in a Nokia S60 phone.
You can witness it yourself by downloading the very good Symbian S60 CellTrack application
available here.

In order to get a valid location reading, you need the cell information from three adjacent towers (3 reference points). This information is only available from the mobile provider. And the accuracy depends on the size of the cells (larger cells in farm land = less accurate, smaller cells (or pico cells) in urban areas = much more accurate).
Google could be using a third-party provider to get that information like
KnowledgeWhere in Calgary, Alberta. But I'm pretty sure they build that infrastructure internally to ensure compatibility with the
Android platform and it's integrated Location API.
However I latched onto something very interesting while listening to the
demonstration video : "
the service gets better the more you use it" @ 1:51.
Why is this of importance ? Why would it get better ? The towers are not moving, the cell ids are very static. Perhaps their database of cells gets better.
So I'm venturing that Google is (
perhaps) sending cell id information to their servers when users are enabling their cell-phone GPS chips to augment their cell location information. That is very feasible and was demonstrated early on by the
PlaceLab project which folded into
Skyhook Wireless somehow.
This way, as more people are using GPSs, they would provide more location information about cells and in return would augment the accuracy of the "My Location" service.
Location-Based Services are being push forward again and thanks to Google for doing it so.
Happy location reporting - Martin
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