Analysis of Mobile Phone Geolocation Methods Used in US Courts

Abstract

Call Detail Records (CDR) are files that collect information about every call made on every cellular wireless network in the USA. Network operators capture and archive these files in the regular course of daily operations for internal use by their technical departments, but CDR files are also used as evidence in criminal cases to estimate the locations of mobile phones and infer the locations of individuals. Courts are tasked with determining the admissibility of evidence and are sometimes presented with CDR interpretations that are not based on legitimate radio-frequency (RF) engineering science. This paper discusses CDR-based geolocation methods that are well founded in the science of RF engineering as well as methods that have no basis in RF theory nor any engineering practices.

Corrections to “Analysis of Mobile Phone Geolocation Methods Used in US Courts”

“…In the above article [1], a typo error caused reference [28] to be omitted from the reference list at the end. It affected all subsequent reference numbers, which were offset by −1 relative to the main body of the text where they were referenced.…”

“…In addition, from an online comment recently posted on the IEEE Xplore webpage for [1] by Mr. Nicolas Dubois from ''Forsk,'' we learned that Figs. 2 and 4 in [1] were apparently not the predictions by their RF Propagation tool ''Atoll'' for a real operational network as we believed at the time of writing.…”

“…In addition, from an online comment recently posted on the IEEE Xplore webpage for [1] by Mr. Nicolas Dubois from ''Forsk,'' we learned that Figs. 2 and 4 in [1] were apparently not the predictions by their RF Propagation tool ''Atoll'' for a real operational network as we believed at the time of writing. The comment suggests that the predictions were for demo networks, meaning the networks that ''Forsk'' experts designed to illustrate typical ''Atoll'' outputs in their technical documentation (User Guides for ''Atoll'' in the case of Figs.…”

“…Figs. 2 and 4 in [1] were reproduced to illustrate that in any cellular network on real terrain, the borders between sectors on different cell sites tend to be highly irregular in shape. In contrast, the boundaries between sectors on the same cell in most cases tend to be linear (''wedge-shaped'') in versions of Best Server maps with and without overlap (an explanation and several rather rare exceptions for the case of sectors on the same cell are described in Section VIII of [1]).…”

“…In addition, we would like to clarify that Fig. 6 from [1] was created for a demo network in the Chicago area (showing a real one from this area would have potentially breached Non-Disclosure agreements that ''Forsk'' has with their customers who operate cellular networks in Chicago).…”