Of course you don't need GPS in a mobile phone... On a normal GSM/GPRS/UMTS network a mobile phone can be located up on a few meters, with a cross pointing location ... This is used in Europe quitte often by the police and gouvernment. If the Network Provider sells there mobile phone numbers/lines to companies that also want to know the location of those devices (workers), there is nothing that has to be changed in their network to enable this. So , yes big brother is watching you. Also swapping phones, or prepaid cards etc. doesn't help ...