His cell phone would need to be GPS enabled, and you would need to have a GPS tracking device.
Here is one website that might be what you are lookig for
Anothersolution is to locate a "spy" store in your aea, pop in and ask them if they can help you accomplish this. you might do better just buying a small tracking device which you could hide somewhere, like in his car and track him that way.
Try this website as an example of what I am talking about
Good luck. If this helps please hit ACCEPT and leave positive feedback.