The days of only law enforcement agencies being able to use a GPS cell phone locator service are in the past. It seems to many that being able to locate someone with their cell phone is likely to be a special effect from the movies.

Remember the days when you would watch star trek on television and they could locate Captain Kirk on their "long range scanners" and "beam him up"? Well unfortunately we haven't evolved to the point that you can find out where you kids are when they are late for dinner and beam them home. Maybe someday though. I'm keeping my fingers crossed!

The traditional way to locate cell phone is with a method called triangulation.

When a cell phoned is turned on, it immediately begins to search for the nearest cell phone tower by broadcasting it's ESN (electronic serial number). When it has found a tower, the tower sends a signal back informing the phone of the tower ID number and the signal strength.

Cell phone towers have a certain radius in which they can communicate with a cell phone. This range is represented as a 360 degree circle around the tower. Step one to locate cell phone through triangulation is for the tower to calculate how far the phone is from the tower. It then calculates an imaginary circle that is sized based on the phones distance from the tower. This is circle "A".

Since there are several towers in any given area, the phone also knows how close it is to the surrounding towers. This is so that when you travel, the phone can automatically transfer it's signal to the next strongest tower to prevent dropped calls. The second nearest tower calculates the cell phones distance and again makes an imaginary circle based on the distance the phone is from the tower. This is circle "B".

The third step to locate cell phone through triangulation is for the next closest tower to gather the same data as the first two did. Once again an imaginary circle is recorded. This is circle "C".

A central computer located at the cell phone company knows the exact location of each of the towers reporting the proximity of the cell phone being tracked. A software program overlays circles a, b, and c. The point at which all three circles intersect is the location of the cell phone. It's as simple as that.

The technology of locating a cell phone with triangulation merely provides a close approximation of the location of the phone. It is usually accurate to within 100 meters or less. In most instances, this is level of accuracy is fine. There is a more accurate cell phone locator services that use GPS technology that is emerging as people replace their old phones with the new smart phones like the ever popular i-phone.