Establishing if a person has been involved in criminal activity, and if so, to what degree; often requires an understanding of a person’s geographical movements. Cell site analysis provides greater clarity to investigators and juries; on whether someone may have been involved in an incident, and if so, the amount of involvement. If you have a prosecution or defence case where you need to establish the whereabouts of an individual, to incriminate or eliminate them from an incident; then you may be able to establish their location at any given time using cell-site analysis.
Call data records are fundamental to cell site analysis, they appear as a bewildering mass of numbers and complex information. CCL has the knowledge to understand hidden patterns in these call data records, and combined with cell site analysis, the evidence can be used to determine the geographical location of an individual, before, during and after an incident; giving defined time lines.
Our expert team of cell-site analysts have decades of experience, comprehending the intricate and complex world of mobile phone masts, raw data and signal strengths in multiple locations (with driving and walking surveys*). They are Bond Solon trained and registered to offer expert witness services; with ‘jury friendly’ mapping and presentations, working closely with you through all stages of the process.
Our philosophy is to keep it simple for our customers when they use the evidence we supply, with our experts on hand to explain any complexities in the cell site analysis. We can process cases quickly and accurately and provide cost-effective prices within LSC guidelines. It is important to CCL that you are confident our analysis and reports are of the highest quality, providing evidential integrity.
When a mobile phone makes, or receives a call, text, or accesses the internet, it makes a radio connection to the phone company’s core network via the network’s transmitting equipment (cell site); the call is routed to its destination by the core network.
In general, a mobile phone will connect to the cell with the strongest signal; however, there can be variations of signal strength over small distances (e.g. an obstruction between the phone and the closest cell, in which case a more distant cell would be used). UK mobile phone Network Operators have many thousands of cell sites, often housing several sets of transmitting and receiving equipment; designed to provide overlapping coverage to ensure a good quality of service. Thus, at any distinct location it may be possible for a mobile phone to connect via several different cells, or cell sites to make or receive a call or text message.
When a call or text message is sent, or received by a mobile phone, the network operator generates a call data record. This record contains: telephone numbers involved in the call event, the date, time and duration of the call event, a code for the handset and the identity of the cell site for which the call began and ended the communication.
A location survey is used to assess which Cell IDs could be used near a particular spot. To do this, special test equipment is used which monitors the mobile network and tracks its own location. *This equipment is fitted in a vehicle and a concentrated drive survey is performed at hundreds of points in the streets immediately surrounding the location (measurements may also be undertaken using hand held equipment in a ‘walk survey’). Every Cell ID providing service in the vicinity is reported.
The data collected from these surveys can be plotted onto maps and analysed, to illustrate the locations of the specific cells the phone was connected to. From these measurements, service area maps can be derived. The service area of a cell site is the area in which a caller who connects via that cell site could reasonably be expected to be within.
The cell’s service area is predicted using the available survey data together with terrain information.