Here is an article by M.Cherry (and others):
http://educatedevidence.com/Viewpoint_J-F.pdf
The actual Court paper in the Antonio Evans case is this one:
http://celltowertracking.com/Daubert_Order.pdf
Some snippets:
Quote::
Special Agent Raschke testified that using a theory of granulization he can estimate the
range of certain cell sites based on a tower’s location to other towers. This in turn allows him to predict the coverage overlap of two closely positioned towers. Special Agent Raschke testified that he has used this theory numerous times in the field to locate individuals in other cases with a zero percent rate of error. He also testified that other agents have successfully used this same method without error. No evidence was offered, however, beyond Special Agent Raschke’s testimony, to substantiate the FBI’s successful use of granulization theory or its rate of error in the field.
Despite Special Agent Raschke’s assurances, the court remains unconvinced that granulization theory is reliable.
First, in determining the coverage overlap of the two towers used by Evans’s cell phone on August 24, 2010, Special Agent Raschke assumed that Evans’s cell phone used the towers closest to it at the time of the calls. But as previously discussed, there are a number of factors that could have caused Evans’s phone to connect to these towers even though another tower was closer. For example, a building could have obstructed the phone’s access to the closest tower or the call could have been rerouted due to network traffic. Special Agent Raschke acknowledged these factors but did not fully account for them in his analysis. Rather, he relied on his training and experience to estimate the coverage overlap between the two. Estimating the coverage area of radio frequency waves requires more than just training and experience, however, it requires scientific calculations that take into account factors that can affect coverage. Special Agent Raschke presented no scientific calculations and did not consider a variety of relevant factors. Although the call data records upon which he relied are undisputed, the link between those records and his conclusions is deficient.
....
Second, the granulization theory remains wholly untested by the scientific community,
while other methods of historical cell site analysis can be and have been tested by scientists.
....
Granulization theory has not been subject to scientific testing or formal peer review and has not been generally accepted in the scientific community. These factors weigh against a finding of reliability.
Given that multiple factors can affect the signal strength of a tower and that Special Agent Raschke’s chosen methodology has received no scrutiny outside the law enforcement community, the court concludes that the government has not demonstrated that testimony relatedto the granulization theory is reliable. As such, testimony concerning this theory, along with the estimated range of coverage for each of the towers indicated on summary exhibit 6, will be excluded under Rule 702 and Daubert.
jaclaz
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