Cell phone tracking can be classified as network based and handy device based.
The former way does not require the mobile device do anything, so it means you do not have to change anything to your mobile phone, the base station will calculate the distance, determine its rough location.
The latter way requires the mobile device to install some location app to acquire the GPS coordinates; it may means you need a GPS receiver and calculate the relevant data, or send the raw data to a location server to do the job.
However it easy said than done, there are more work to do in order to track a cell phone, you need mobile internet to send the data, and a server to receive the data, process it, and then show the data on a map like Google Maps.
Source: cellphonetrackers.org
