There are many numbers of ways these days to track cell phone location. It may seem like a strange goal to track someone by their cell location but in many circumstances it can be extremely important to know or have an idea where someone might be. Numerous different hikers, divers and all sorts of other adventuress have had their skins saved by people being able to track cell phone location via their cell phones. In most phones, but not all, there is a little chip in the phone itself that gives out a signal that can be easily tracked.
So as long as the phone is at least one of the more modern cells built in the last 10 years or so, it can be tracked by relative ease. This is due to the fact that the cell relies on a relay from a larger tower that projects signal outward around it in 360 degrees to different cell phones in the area. The phone then pick up this signal and bounce back a message, usually a call or a text message if you would. From this exchange the tower can track how many phones are within its area along with a general location of where they are bit direction and proximity.
This is how larger phone companies track phone location around their towers. Other methods could also be used to, like Bluetooth. Bluetooth, aside from being a very helpful headset design and trademark, is also a proximity locater for other sources by which the phone can be connected to the internet wirelessly. If a phone is connected to the internet, even if it is wireless then it can also be used to track cell phone location so long as the cell is within the Wi-Fi zone
This works but the fact that the router that runs or puts a zone around it that is invisible to humans that provides internet. A cell can tap into this internet and use it for its own purposes. However the way to track cell phone location via this is that the router tracks and logs either the MAC address that is unique to the phone itself. Since this is logged as soon as the cell syncs up to the internet within the Wi-Fi zone the phone is instantly on the internet and therefor instantly trackable.
Hope this info helps, best of luck to you tracking your phone!