@DeepCopy; fuck your flashy picture of doom
@OP; cellphones still use towers. Cell towers still report information on connections for maintenance, statistics, tracking, whatever. Cops can have access to this information. Because cellphones can connect to multiple towers, and signal level can be calculated, you can triangulate the approximate position of any connected device. Cellphones use towers from any tower that they can connect to so what service you use doesn't matter. Services like 'wifi calling' do not normally affect the accuracy of retrieved information as, even though cell towers may not be used for calls, they're still used to some degree. You might be able to prevent the cell tower use but that may be a different process for each phone and/or service.
Try hacking a cell tower or 3. If you can make sense of the info you receive, it can be quite enlightening.