Call detail record mapping can be a challenging task to accomplish if you are not sure of what the proper industry standards are. Do I just put a dot where the cell tower is? Do I need to figure out what kind of area this specific tower covers? Am I only concerned about the general area where the phone may be? These are legitimate questions that come up for all investigators and analysts when doing any kind of cell phone mapping.
What we can tell you is that there is a right way to map your CDRs…and it’s not determined by us.
There are two facts in the CDRs that remain undisputed: the location of the cell phone tower and the direction of the sector (or side) of the tower that was used. Every sector faces a specific direction and the cell phone carriers call this the “azimuth”. This is just a fancy word for direction. For example, if you see that sector 3 on cell tower 303 has an azimuth of 270, then that sector faces 270° (or northwest). Since those are clearly stated in the CDRs you should have no problem showing that in your maps.
Sometimes investigators feel that they want to go a step further and try to show the exact area where a phone was. This is known as Radio Frequency Coverage Area (RF Coverage). It is true that cell towers cover a certain area but the cell phone carriers don’t include that information in their CDRs. If you try to take liberties with the data and go beyond what is in the CDRs then you will have trouble when on the stand. Savvy attorneys will create havoc for you and your exhibits if you go this route but if you just stick with the facts (location of cell tower and direction of the sector) you will be fine!
Luckily for us, the Scientific Working Group on Digital Evidence (SWGDE) set the industry standard back in 2017 when they published “Recommendations for Cell Site Analysis”. This group of digital forensics professionals works together to develop the industry best practices when it comes to working in the digital forensics field, including CDR mapping and analysis.
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