One of the best parts about litigation is that, with each new case, I learn about a new and different industry. To effectively proceed with the case, it’s incumbent upon the attorneys to learn as much as we can about the rules, regulations, or technologies at issue. Recently, the use of cell phone technology, and GPS tracking through service providers, became one of my areas of study. The results of this deep dive into cell phone technology were both a little bit sobering and a little bit heartening.
First, let’s take a glance into the technology and how cell phone tracking works. Cellular phone providers are tasked with setting up a cellular network to provide coverage for their customers across the country and across the world. Cell phone towers in wide open areas can provide service for up to a 25-mile radius around the tower. However, in congested, dense cities with tall buildings, this requires a huge number of cell phone towers that usually only cover several city blocks. Large buildings, built from solid materials, can successfully block cell phone signals, leaving the customer without service. Cell phone providers, therefore, try to cover every block and every direction, to provide smooth cellular coverage to their customers.
Each of these cell phone towers has a precise location, with latitude and longitude coordinates. The cell phone provider will be able to provide the location of various cell phone towers. On top of this, each cell phone tower is comprised of, usually, three sectors, pointing in different directions, to form a triangle that covers 360 degrees. Each time a cellular phone attaches to a particular cellular tower, the records indicate which sector the cell phone pinged. In other words, if your cell phone pinged off the northeast tower sector, the records will indicate that you were generally in a northeast direction from that cell tower, which narrows down your exact location.
As you move around, and use your phone for various different purposes, you are creating a record of your usage and your location. This is captured in what is referred to as a “Call Detail Record” and would be received from the service provider in response to a subpoena. As your phone attaches and reattaches to different cell towers, it becomes possible to see in which direction your phone is traveling.
In order to more closely pinpoint your location, it is important to understand that a cell tower providing voice and text message service does not also provide data usage. So, if you are receiving text messages throughout your day, and also opening and closing a web browser or a mapping application, you are connected during those times to two different cell towers. Specifically, you are connected to two different sectors on two distinct cell towers. Where those coverage areas overlap provides a fairly good indication of the city block you are standing on.
When you are attempting to use your phone, but there is a lack of signal strength, or you are blocked by a building, your phone remains aware of the closest available cellular tower for the purpose you need service (data or voice/text). The phone continues to attempt to connect to the closest appropriate cell phone tower. The only time your movements and location are not being tracked is when your phone is completely off and not receiving voice/text messages.
The takeaway from all of this is that our phones are always on, they are constantly using data service to receive our emails, text messages, and calls. We are constantly opening and closing various applications that require data usage. Which means that all of us are frequently connected to two different cell phone towers. Based on the sectors we connect to, and where those coverage areas overlap, the cell phone company, or a party who has served a subpoena for your call detail records can pinpoint your location fairly closely. This is particularly true in a dense city location, where there are many, low-range cellular towers that cover only a couple of city blocks.
In the middle of a long drive through Utah, the cell phone towers cover much longer areas, and it is more difficult to pinpoint your location exactly. The call detail record would be able to track, generally, the direction of your travel, and what town you stop in. But, in the city, all of the constantly pinging cell phone towers keep close track of our movements and where we are at any given time. If you’d like to refrain from being tracked entirely, you’ll have to shut that phone off. In this world, our friends and family may appreciate that!
