Regarding tracking mobile phones and privacy there is some good info in these IRC logs related to multilateration and U-TDOA, and that the precision of locating a mobile phone signal is comparable to that of GPS (given enough towers):

http://infobot.rikers.org/%23neo900/20140904.html.gz http://infobot.rikers.org/%23neo900/20140910.html.gz

  "DocScrutinizer05:	note that a cellular device that's logged in to network doesn't need any fancy GPS to locate your postion down to 1m precision"