How Cell Site Analysis Defence Works:
Initial Review Of Prosecutions Cell Site Analysis
The defence team will instruct an expert in Cell Site Analysis, ( Matt Jones +44 (0) 1827 50000 ) to review the prosecutions Cell Site report. This review will entail verifying all the maps and associated documents are both accurate and do not have any errors, the examination methodology and equipment used.
Once the Cell Site Review has been undertaken, in most cases, to fulfil the obligations of defence counsel, it is necessary as part of the review to re-examine a portion, (or all), of the cell site analysis work. This is undertaken to ensure that the original readings are accurate as an incorrect reading could mean that the suspect has been attributed to a place that he or she wasn’t. The examination aspect is conducted utilising the same methodology used for a full re-examination (see below).
Cell Site Analysis Re-Examination/Examination
The analysis is generally conducted in one of two ways: Either it will involve travelling to each location of interest highlighted by the prosecution and taking measurements to determine the best serving cell or cells with respect to each specific location. This is known as a ‘Spot Report’. The second re-examination option involves travelling in and around the area covered by a particular cell to determine the overall coverage. This is known as a Full Coverage Report. The Full Coverage Report frequently involves numerous hours of cell site readings, depending on the geographic area covered by the cell. It should be noted that cells located in city centres generally will cover a smaller area than those located in rural areas.
Both ‘Spot Report’ and ‘Full Coverage Reporting’ methods provide a validated indication to the coverage of the cell, however, a Full Coverage Report can geographically be represented on a map to show the extent of coverage with the most probable areas or locations where the call is most likely to have been connected. Spot Reports will only show the coverage measured at specific locations, and does not represent other areas where a call may have connected. Each case has to be determined as to which is the appropriate examination is to be used.
The specialist network equipment used to conduct these measurements is essentially a mobile phone enabled with specialised software and a GPS system which is installed within a vehicle. This bespoke equipment will allow the user to monitor, or if necessary adapt, the way in which a mobile phone responds to the network. This bespoke equipment is also connected to a GPS system which can record the precise location where each measurement is taken.
All the measurements recorded by the Cell Site Analysis Expert are then complied in to ‘logfiles’, which are then analysed back at the laboratory. The analysis of this data is manually undertaken and is often very time consuming. The data is then plotted onto ordinance survey maps to show which cells provide coverage with respect to a single location, or the full coverage plots.
The results of the readings are used to compile a new report. The new report is then analysed against those from the prosecution’s report, to ascertain if there are any discrepancies. If any discrepancies are found, they assist in the defence by discrediting the prosecution’s evidence or if its inaccurate, the prosecution’s evidence/case is likely to be thrown out.
All findings are complied in a clear and concise report with associated ordinance survey maps of varying scales, to visually represent locations of interest and cell coverage.
Cell Site Analysis Defence – Why Do We Need This?
Cell Site Analysis is predominantly used by prosecution to prove the whereabouts of a mobile phone at a particular date and time. It is important to note that Cell Site Analysis only proves where the phone was, not the user, (though it’s frequently simple to ensure that the phone was in the possession of the suspect by examining texts, phone calls etc).