Phone baseband proprietary stack is bombarded with type0 SMS which will silently ack the msgs and thus 'ping' your location. There's probably carrier made track

Phone baseband proprietary stack is bombarded with type0 SMS which will silently ack the msgs and thus 'ping' your location. There's probably carrier made tracking programs on SIMs too and/or your SIM can be modified by over the air update to install stealth tracking programs the host OS will never know about. FBI asked a carrier to do this once to track a fraud suspect http://www.wired.com/2013/04/verizon-rigmaiden-aircard/all/ http://www.wired.com/2013/04/verizon-rigmaiden-aircard/all/