I run a cleaning business and am building some software to help with the management. I want to have a system which monitors when a cleaner starts and finishes a job. Ideally employees place a call to some sort of exchange, and punch in a code which identifies them in addition to logging the start time and location. I know the first part of this (calling a number to effectively 'punch in') is possible, but I don't know whether its possible to get their gps location from a call. I also know there are lots of smartphone solutions but many of my cleaners do not have smartphones.
Is this possible and if how do I go about developing this?