Explanation
Explanation
How does it work?
GG-Tracker tracks your mobile using GSM Cell-location in combination with GPS. It uses both GPS and GSM networks to get a position. If only GSM is available it relies on location previously stored using a GPS receiver or the CellDB.org database. This product is in a developmental phase and is only here to show you how it can be done.
The operation is very simular to Google Maps 'My location', only this time you are in control. If a GPS receiver is connected it does two things, it stores the current position and the GSM cell the phone is connected to.
This position is relayed from your phone to your server using internet. The packages are pretty small to keep costs as low as possible. Personally I use Aspicore GSM Tracker to relay those positions back to me. They are then captured by a modified version of the Aspicore PHP files.
If the GPS is not connected anymore it checks the database for previously known coordinates of the GSM cells. When it was connected to GPS the program stored the GSM cells, so all it does, is look back and see if there is a proper fit. As a backup the CellDB.org database can be used to retrieve the location. If it finds a fit, it reports that as a position, meaning that GPS is not necessary anymore for positioning.
If you like to compare GPS results with GSM results please see the images 'GG-Tracker, no GPS' and 'GG-Tracker with GPS' below. It shows a picture of the same travel with and without GPS. Please be aware that everything is experimental and that GSM positioning is as precize as GPS positioning, but it is faster and not everybody has a GPS attached to their mobile phone.
What is this CellDB.org database?
CellDB is an open database which links the cells that make up mobile networks, to their location. Cell locations can be used for location deteminence of mobile handsets. Currently, most applications create their own cell database. Their philosophy is that these applications should compete on features, not on cell coverage. If they use a common database, all applications will work better, enhancing the user experience. That's why they build an open database, that any application can use.
