Skip to main content
 
 
 

A Simple Guide to the Cell Site Process

A Simple Guide to the Cell Site Process

Cell Site Analysis process - a guide by Dr David Schudel, Forensic Scientist, Keith Borer Consultants

The Police intelligence analyst will use different sources of data to produce a timeline or schedule. Included may be the movement of a phone, who the phone was in contact with, sometimes the content of a message, ANPR information, as well as CCTV cameras stills and vehicle tracking data. The final document can be a combination of several different sources of information that may require different experts to independently assess.

The mobile phone portion of the evidence itself can be a combination of three things. These are:

  • Mobile phone download: This is information extracted from a phone itself and contains things like the content of text messages, images, and app content such as WhatsApp messages. Because information can be deleted, the download might not show all the calls, texts, images or communications made.
  • Connection Records: These do not come from a phone but are provided by whichever of the four networks the phone SIM card or cards has been used with. The four main networks are EE, Three, Vodafone and O2. Other networks, like Tesco or GiffGaff, have one of the main four behind them. The connection records contain the date, time and the other number the phone was in contact with as well as the type of contact: SMS, MMS (both types of text messages) or a normal phone call.
  • Call Data Records: These are similar to connection records, but in addition the above, the “cells” that were used to connect the calls or texts is provided. If the phone can access internet data, then mobile data (also called GPRS data) can also be requested that will list dates, times, cells and duration used.  For O2 only, there is another layer of data that can be requested called “DDR” that are system transactions. Normally, these are requested for small timeframes only, such as a single day, due to the high volume of data available.

It is call data records that form the basis of Cell Site Analysis.

The Cell Site Analysis (CSA) Process

The CSA process is relatively straight forward: First, get a copy of the raw call data records. Analyse them. Assess if a Radio Frequency survey is needed. Combine the analysis and RF survey together and do a report. Simple if time, funding, and complicity were not an issue.

The first hurdle from an independent expert perspective is often getting a copy of the raw call data records. Initially, the Police request call data records from the network who provide them in a .CSV file format. The police often load them into third party software and create their maps, schedules to put their case together. When the independent expert asks for a copy of the same raw data, they may receive a PDF copy (which can’t be used) or an Excel version that has been altered from its original by things like redaction, deletion or processing by other software with nothing to show that the altered version is materially the same as the raw. In these instances, the data at its best carries a degree of doubt and, at its worst, is unusable.

It is imperative to seek a copy of the raw data as early as possible to allow for the weeks it might take to get it. Without a copy of the raw data or at least a workable copy, the independent expert won’t have the benefit of using the same data that the Crown has used to create its case, which puts the Defence at a disadvantage.

With suitable call data records, it is possible to map out the location of a cell, the direction it points and the date/time it was used for each record. For each record, the general location of a phone can be assessed and by combining these you can create a movement map of a phone. This is the core of cell site analysis. In a large case, we may be mapping tens of thousands of these, which is why having sufficient time to review the data is vital to enable a fair look at the evidence.

In CSA, what is meant by general location of a phone?

Depending on things like the cell height, type, technology it is using and the surrounding terrain, cells can provide a service for relatively short distances of ½ to 1 km up to several kilometres, and in an arc centred on the cell going out around 120°. For this reason, it is not possible to say a phone was in a specific area using cell site analysis. The location will always be an area.

What are RF Surveys?

Cell site analysis can be underpinned by RF Surveys. These are created by going to a place or driving a route and using specialised equipment to measure cells active in that spot. If a cell is detected, then it can help to show where are phone may or may not have been. The problem with RF surveys is that they often do not detect all the available cells. In other words, even if a cell is not detected it does not mean that the cell will not provide coverage to that area. This is made more complicated by the fact that all surveys are done after the fact whereby cells may have changed/been decommissioned and also are done at street level, whereas phones are often used inside homes on floors above ground and potentially, exposure to different cells.

In other words, you cannot rely solely on RF survey results as an accurate depiction of cells in an area. There has to be consideration of those that may serve despite not being detected or were detected but at a weaker level. This is often missing from the Intelligence Analyst’s approach which focuses on the cells detected only.

How reliable is cell site analysis?

CSA can provide very strong circumstantial evidence if collected, analysed and then portrayed correctly. It can often “make or break” a case. There are general limitations to be aware of which are:

  • CSA cannot identify who is holding a phone (called attribution), but things like common movement, common area of “residence” and the pattern of calls to people like family members and other landline numbers such as taxi companies, fast food establishments etc can support or refute its attribution. “Top Up” locations may also assist.
  • CSA cannot pinpoint the location of a phone at a given time. It can only say the phone was in a certain area which can be from one to tens of square kilometres in size depending on numerous factors. The area of operation can be more precise if there are several cells within a short period of time indicating that the phone must have been in an area of shared coverage.
  • Depending on the type of records used, CSA can give a precise time a cell was used (for calls, texts and generally for DDRs) or an imprecise time (for mobile/ GPRS data). This may not be obvious to a lay reader. GPRS records also vary in their interpretation according to the different service providers.
  • The shared movement of two different phones (called co-location) may not involve use of the masts in the same places but can still be assessed. Generally, the further the distance travelled, combined with sufficient available data, the greater the power of co-location analysis to support or refute the phones were together.
  • There are cases where CSA is simply not appropriate, such as involving very short distances, especially in and around normal residence or work areas.

Seek expert advice

If in doubt, it’s best to have an expert look at the data. Bear in mind, some CSA cases are vast and cell site experts are not plentiful; many have wait lists lasting weeks or months. It’s good to get ahead of this evidence and allow time for it to be reviewed where possible. If the evidence has been served late, then the Court should be made aware that it may take a while for an independent review.

We at Keith Borer Consultants have four cell site experts on staff: Stephen (Jack) Frost, Andrew Dampier, David Schudel and Thomas Marryat. We’re always happy to assist and can advise accordingly. Email us at kbc@keithborer.co.uk (or kbc@keithborer.co.uk.cjsm.net), call us on 01913324999 or take a look at our website: www.keithborer.co.uk.

Tweets by @KBCforensics 

Subscribe To Mailing List

To unsubscribe click here

What our customers say...

  • Clear advice given at start and very prompt response.

    Private Client, March 2021
  • Brilliant communication, my emails were promptly answered.

    Private instruction, September 2020
  • Thank you for your hard work in this case and for the prompt responses. 

    Barrister, March 2020
  • Extremely good customer service and continuous contact/support.

    Solicitor, November 2019
  • Very fast, professional, easy to instruct.

    Solicitor, November 2019
  • Excellent, as usual.

    Solicitor, September 2020
  • I have been instructing KBC for over 15 years and have always been happy with the service, contact from experts and quality of the reports.

    Solicitor, December 2020
  • Very approachable.

    Solicitor, November 2020
  • I have worked with Mr Donnelly in many cases over the years and his expertise, presentation of written work and ability in the witness box is second to none.

    Counsel, November 2020
  • I can say that I am very satisfied with the service I have received from KBC, starting with my initial phone call and interaction your colleague when I made my initial enquiry, right up to the report being received. I would certainly use KBC again and would recommend you to my colleagues.

    Solicitor, January 2020
  • Simon Bunter is as good an expert as I have ever worked with.

    Barrister, December 2019
  • I chose KBC because it has a good reputation and the price is very fair.

    Private client, April 2021
  • A thorough analysis, with well set out conclusions.

    Solicitor, July 2020
  • I find KBC invariably helpful and reliable.

    Solicitor, December 2020
  • Just a very high quality, professional service.

    Solicitor, December 2019
  • No question was too silly and everything was explained so clearly and easily; great customer service.

    Private instruction, September 2020
  • Mike Appleby's exceptional quality was noted by all of the Counsel involved in the case. It is always a pleasure to watch someone, who is good at something, doing it and doing it well.

    Barrister, December 2019
  • There are times when DNA evidence can be a little dry, but Mike Appleby's presentation and delivery to the jury was pitch perfect.

    Barrister, December 2019
  • Mr Ebejer was always very professional and friendly.

    Solicitor, August 2020
  • I am extremely grateful to you for all your work on this case, in particular your prompt and helpful responses to my repeated requests.

    Barrister, February 2021
  • Friendly, approachable, amenable, accommodating, professional.

    Instructing party, April 2021
  • Quick and efficient; and well laid out report.

    Solicitor, November 2019
  • Report well presented. Concise and precise.

    Solicitor, February 2021
  • Very quick turnaround, with attention to detail and helpful comments.

    Solicitor, January 2020
  • Always a pleasure working with you guys; our first choice for instruction.

    Solicitor, November 2019
  • Provided helpful information above and beyond what was expected.

    Solicitor, February 2021
  • We have used your services for some time and are very satisfied.

    Solicitor, November 2019
  • Really happy with all aspects of this case and would definitely recommend this company. Thank you.

    Private instruction, September 2020
  • Thank you very much, I am grateful and impressed with your service.

    Solicitor, January 2021
  • Website was very informative.  First contact was knowledgeable and efficient. The report was delivered in record time - very impressed!

    Solicitor, January 2021
  • Very impressed; would use again.

    Barrister, April 2021
  • Prompt attention to dealing with queries and providing information and reports.

    Solicitor, March 2020
  • Mr Frost has been a great help in this case and we really appreciate his assistance.

    Solicitor, February 2021
  • Good admin - chasing up correspondence. Quick preparation of report. Easy access to expert for clarification purposes.

    Solicitor, April 2021
  • I always choose you because of the fast, efficient and excellent work you do.

    Solicitor, April 2021
  • Our lawyer is most impressed with your report.

    Instructing party, Guyana, April 2021
  • We have used your services on many previous occasions. You always provide the cheapest estimate and respond quicker than any other service provider we have contacted for the purposes of Legal Aid.

    Solicitor, January 2021
  • Provided quotes quickly and complied with court timescales.

    Solicitor, December 2020
  • Quick, efficient service and a well-prepared report.

    Solicitor, July 2020
  • Karl Ebejer was always prompt with responses and was very helpful.

    Solicitor, August 2020
  • Speedy responses to our instructions and questions asked. Helpful estimated timeframe for the service of reports.

    Solicitor, January 2021
  • Very quick response to queries raised following receipt of report. Very helpful.

    Solicitor, January 2021
  • Jenny Gray was excellent and very helpful throughout.

    Barrister, November 2019
  • We have used KBC on many occasions in the past and have always had a reliable service.

    Solicitor, April 2020
  • Extremely helpful, efficient and above all thoroughly professional.

    Solicitor, December 2020
  • I chose this company, as the first point of contact was extremely helpful.

    Private instruction, September 2020
  • Service was excellent throughout.

    Solicitor, August 2020
  • Telephone communications were very helpful when we were not able to contact the expert directly. The call takers were knowledgeable as to the case and what was required and answered any queries we had.

    Solicitor, September 2020
  • I find your service prompt, efficient and helpful. Alan was particularly helpful and rang me to discuss issues. I was able to understand clearly what he was outlining and think he will be an asset to the defence case.

    Solicitor, April 2021
  • Mr Dunnill’s report was helpful and our conference at Court informative; I would certainly be happy to use him in a case again.

    Barrister, December 2020
  • Knowledgeable, helpful and polite.

    Solicitor, June 2020
  • I used Andrew Dampier for a cell site case and he was exceptional.

    Barrister, November 2020
  • I am very impressed by your service.

    Solicitor, February 2020
  • Fast service; timely response to communication.

    Solicitor, January 2020
  • Courteous and informative.

    Solicitor, December 2020
  • Quick, expert and accurate.

    Solicitor, July 2020
  • Experts are always happy to discuss matters prior to providing report.

    Solicitor, December 2020
  • Swift service.

    Solicitor, March 2020
  • I was told you were the best at what you did. I honestly believe I got what was required.

    Private client, July 2020
  • My impression of your service was excellent.

    Private Instruction, November 2020
  • Speedy and detailed quotes which do not delay funding from LAA.

    Solicitor, December 2020
  • Your (cell site) reports and maps were extremely helpful.

    Barrister, February 2021 ​​​​​​
  • We were kept updated throughout the process and the report was provided promptly.

    Solicitor, January 2020
  • Mr Appleby was truly excellent. While giving evidence it was plain that he has achieved the perfect blend of clarity and authoritative charisma.

    Barrister, December 2019
  • Prompt and Professional and produces excellent reports.

    Solicitor, September 2020
  • Regular contact, advice on hand via phone if necessary, prompt and efficient.

    Solicitor, August 2020
  • Found the service to be extremely helpful, given the timeframe in which the report was required.

    Solicitor, January 2020
  • Andrew Dampier provided first class service in the form of reports and maps. He was able to explain the report in good layman’s terms and was also available to take calls and provide further information to counsel.

    Barrister, January 2021
  • Mr Brown was an impressive witness. As far as I am concerned, you can give him full marks all round.

    Counsel, March 2020
  • Good service, prompt, efficient, have used many times in the past.

    Solicitor, April 2020
  • Past experience has taught us that KBC is the go-to expert witness service.

    Solicitor, March 2021
  • Mrs Allan was most informative and provided explanations where required. A very professional attitude.

    Private Client, March 2021
  • I don’t think the service could be improved upon or bettered in any way.

    Private Instruction, November 2020
  • I have had the pleasure of the assistance of Mike Appleby on a number of occasions now and he is an excellent man to have around. 

    Counsel, March 2020
  • Easy access to experts; excellent communication and advice, as required.

    Solicitor, September 2020
  • Excellent reports within Legal Aid rates.

    Solicitor, November 2019
  • Quick, professional, friendly, comprehensive.

    Prison Governor, June 2020
  • Always provide detailed quotes to assist with applying for authority from LAA. Quick response and good communication.

    Solicitor, March 2021
  • Easy to contact, quick responses (particularly in the current circumstances), very helpful staff.

    Solicitor, April 2020
  • Would definitely use you again; very impressed.

    Solicitor, November 2020
  • Communication and speed of delivery of information was, as always, excellent.

    Solicitor, April 2020
  • There is no question that your input was instrumental in persuading the Defendants to alter their stance.

    Solicitor, September 2020
  • Mr Prime reported to us with great efficiency and presented his evidence to the Jury in an extremely persuasive manner.

    Counsel, March 2020
  • Mrs Morley was very good and a strong defence witness.

    Solicitor, April 2021
  • Prompt provision of report and prompt reply to queries.

    Solicitor, November 2019
  • Excellent client care and service.

    Solicitor, August 2020
  • I will definitely use Dr Schudel in the future and will be recommending him to my colleagues.

    Counsel, March 2020
  • Mr Armstrong impressed throughout the trial as a real expert in his field. It was apparent too that Mr Armstrong was entirely impartial.

    Counsel, March 2020
  • We have used your company numerous times and have always received very well written and easy to understand reports.

    Solicitor, March 2021
  • I was able to have a meaningful conversation with a specialist when obtaining a quote for the work.

    Solicitor, June 2020
  • Mr Beatson was very helpful and professional, clearly with a wide range of knowledge and understanding.

    Solicitor, March 2020
  • Fast response and work turnover time; great customer service.

    Solicitor, November 2020
  • Mr Dampier made an incredibly complicated matter easy to understand.

    Barrister, February 2020
  • Exceptionally efficient service.

    Solicitor, December 2020
  • Thank you very much once again for your excellent service.

    Solicitor, March 2021
  • Mr Fagan was readily available to answer queries very promptly and worked to a tight time limit. He was also extremely helpful in trying circumstances surrounding a refusal by the prosecution to release exhibits.

    Solicitor, April 2021
  • We have always received professional and high standards of services. Reports are produced promptly and communications responded to without delay.

    Solicitor, September 2020
  • Simon Bunter is extraordinarily knowledgeable, remarkably efficient and a wonderful communicator. I cannot recommend him highly enough.

    Barrister, December 2019
  • Value for money.

    Solicitor, May 2020

Keith Borer Consultants is a division of Orchid Cellmark Ltd, a company registered in England at 16 Blacklands Way, Abingdon, OX14 1DY.

Registered No. 4045527; VAT registration No. GB 750 0292 64

Website developed by Problue Solutions