Location: PHPKode > scripts > GG-Tracker GPS and GSM Tracking > gg-tracker-gps-and-gsm-tracking/README.TXT
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. 

Live demo at http://tracker.eppenga.com/

How does it work? 
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 (these 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. 

What is that status?
GG-Tracker show in the GPS information box something called status, what does
this mean? 

A - Active position derived from GPS, GPS is switched on
B - Same as A and also contributed the data to CellDB.org
V - Active position derived from GPS but GPS has no 'fix' yet, GPS is on
X - Position retrieved from SQL Table 'CELL', GPS is switched off
C - Position calculated based on minimum 3 and maximum 10 previous GPS positions, 
	GPS is off. If CellDB.org is allowed status R and T are also used.
R - Resolved through CellDB.org and location is calculated
T - Resolved through CellDB.org and actual GSM antenna tower was found
F - Lookup through CellDB.org failed
Z - Position could not be retrieved by GPS and GSM, GPS is off

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. 

What do all these PHP-files mean?
calc_gearth.php - Internal file to calculate Google Earth history 
calc_stats.php - Used in calc_gearth.php
config.php - Setup your configuration here
config_check.php - Check if configuration is set properly
celldb_org.php - Integration with CellDB.org
footer.php - Customize your footer
gnwlink.php - Write a Google Earth .kml file with current position
index.php - Actual application
math_functions.php - Do the more advanced math
rsscreate.php - Create an RSS feed for syndication purposes
storesql.php - Used to store the data coming from your phone

Is it tested?
One thing I know for sure, it works on my setup, that is:

Nokia N79 Cellphone (N73 also works)
Freedom KeyChain 2000 GPS tracker
Aspicore GSM Tracker 3.20
Apache 2.2.4 Webserver
PHP 5.2.0
MySQL 5.0.27

If it will work on your setup, that's up to you :)

Kind regards,

Ebo Eppenga
E: hide@address.com
I: www.eppenga.com
Return current item: GG-Tracker GPS and GSM Tracking