In many cases, there may actually be more than three cell towers receiving a phone’s signal, allowing for even greater degrees of accuracy (although the pedantic side of me notes that the term “triangulation” isn’t really correct if you’re using more than three reference points). In densely developed, urban areas, the accuracy of cell phone pinpointing is considered to be very high because there are typically more cell towers with their signal coverage areas overlapping. In cases where a cell user is inside large structures or underground, cell tower triangulation may be the only location pinpointing method since GPS signal may not be available.