Cell Site Analysis (CSA) Images Part 2

Cell Site Analysis (CSA) Images Part 2
.

It may interest those reading the discussions that I post that Cell Site Analysis (CSA) results from terrain and clutter analysis and radio test measurements can be defined in many different ways that can demonstrate particular elements of importance to a case.
.

Image 5

.
First we need to model (Image 5) the landscape that represents the geographical area and natural and manmade phenomenon in the surrounding area. In this case the scene of crime is close to a crossroads in the middle of small urban town.
.
For the sake of comfort, juries rarely understand radio coverage that is verbally discussed but respond much better to discussion revolving around a visual aid presentation.
.

Image 6

.
In this particular case I want to show the jury that two microcells* were used and each microcell first needs to be defined (Image 6) to the jury so they have it clearly in their minds the origin and direction of the radio coverage that forms part of the discussion.
.
In the first posting below (Cell Site Analysis (CSA) Images) coverage maps were shown defining large cell/macrocell coverage. Here, it is possible to refine and finesse coverage to a specific area with microcell coverage. Importantly, it is a really good idea to make sure the first image the jury sees represents the first radio coverage that a particular mobile phone has used that you want to talk about.
.

Image 7

.

The second microcell coverage (Image 7) should also be defined and distinguished. It's always best to remember with microcell coverage radio path is shaped in the same way as the High Street. Microcells don't go around corners.

.

Image 8

.

Finally the culmination of the presentation defines how the coverage from both microcells blend (Image 8 ) at particular points along the radio path.
.
*Remember that mobile telephones need to be encouraged to use microcell coverage and the microcell location, coverage boundary, speed at which a mobile phone is moving and cell reselection cause system challenges that required the use of a new criterion that was introduced into the GSM Phase 2 Standards in 1996. Do you know what that criterion is called and how it works?
.

Lastly, having mentioned microcell and large cell, the image below (Image 9) represents a visual indication about very important technical aspects concerning radio coverage and the layers depicted are often referred to in evidence. Indeed, if you care to read some of the Mobile Telephone Case Law you can find Appeal Courts referring to the importance of comprehending how far coverage extends.
.

Image 9

Cell Site Analysis (CSA) Images

Cell Site Analysis (CSA) Images
.
Cell Site Analysis (CSA) has had a good deal of airing recently here on the forum, so I thought you might like to see images from the work that I get involved.
.

Image 1

.
Image 1 is one slide from the training course material to introduce students to CSA when starting out discussing radio test measurements. It should be noted that this image represents less than 1% of all data acquired during radio test measurements.
.

Image 2

.

I thought it would be useful to include this Terrain and Clutter Map (Image 2) as I use this software to assist me in complex cases. Terrain and Clutter are discussed during training and as it was a topic of the discussion about UK Criminal Evidence Delays I thought it would be helpful to let forum members see that I am not referring to theoretical matters, terrain and clutter analysis actually takes place.

.

Image 3

.

It is essential to understand, when conducting radio test measurements, that just because radio signals can travel some distance from a particular Mast (Image 3) that coverage should not be dismissed or excluded. Operators set threshold limits, hard limits and boundary limits. It does not follow that just because a mobile is in the Green area shown in the Single Cell Prediction Map that the mobile will be excluded from using that coverage.

.

Do you remember the discussion that I put up here CSA: Mobile Phones and Fringe Coverage?:
.

Image 4

.

Best serving coverage is often posed as the deal-clincher to suggest the mobile phone was most likely or consistent with being at a particular location. There can be numerous points that could (and I say 'could' advisedly) point to best server coverage being used but rarely does it come up in evidence because the radio content in evidence rarely gets disclosed these days.

.

It is possible with best serving coverage that it can induce a negative outcome that may prevent calls taking place, so it is always important to see the other side of the coin, so to speak:
.
GSM Radio Test Measurements Non-Dominance
GSM Radio Test Measurements
.

I hope the above provides a further illustration of how smart and intelligent a science Cell Site Analysis really is and that by not applying it properly and dumbing down this art of this forensic science:

.

- is not only a great loss to the law of evidence

- it reduces the examiner's/expert's knowledge and understanding about the subject with which they are dealing - mobile telephone evidence.

Cell Site Analysis - Criminal Case

Cell Site Analysis - Criminal Case

IN HER MAJESTY'S COURT OF APPEAL IN NORTHERN IRELAND

Neutral Citation no. [2008] NICA 5

THE QUEEN v RICHARD DAVID McCARTAN and BARRY DAVID SKINNER.

Appeal Court: Kerr LCJ, Campbell LJ and Morgan J

http://www.courtsni.gov.uk/NR/rdonlyres/4F39A7FC-5350-4E4B-BB76-FA8DC4BA08D6/0/j_j_KER7057Final.htm


It is not proven with cell site analysis that evidence obtained relating to mobile call records, the Masts and their details associated with handling the calls and conducting radio test surveys combined together form a precise indication of the geographical location of a mobile telephone at the material time. Therefore, it is unlikely an alleged opinion that it is consistent to place a mobile telephone at a particular location holds weight. That cell site analysis might generally indicate the possible movement of a mobile telephone in relation to Masts that it used and no more.

Whilst the Appeal Case for the appellants (McCartan and Skinner) did not succeed it was not because cell site analysis was able to pinpoint the location of the appellants' mobile telephones, which it is unable to do, but the appellants' failure to identity what was happening with their mobile telephones at the material times. The following commentary from this Appeal Case is worth reading.

'The cell site analysis

[37] An expert in this field, David Sanderson, gave evidence, submitted a report on the subject and made a Power Point presentation to the court. Mr Fee suggested that Mr Sanderson’s evidence established that (a) call mapping was carried out in respect of telephone 008 (attributed to Mr McCartan) and telephone 301 (attributed to Mr Skinner); (b) call mapping provides an approximate indication of where a mobile phone was when a call was made; (c) call mapping is used primarily to show the likely movement of a cellular phone with a general indication of location; (d) the cellular phone may be anywhere within the best serving coverage of the sector; (e) there is boundary overlap between sectors served by different masts; (f) the extent of the best serving coverage sector is unknown; (g) the indication of movement of the person using the telephone is no more than consistent with a suggested pattern of progress – it cannot establish positively that the user of the telephone in fact moved in the mooted direction; (h) calls 15, 16 and 17 from 008 at 20.53: 20.55: 20.55 were made when the telephone was not in the vicinity of Euston Street.

[38] On the basis of this evidence Mr Fee argued that the cell site analysis did no more than provide a very imprecise indication of general movements. In the absence of a capacity to identify a precise location of the telephone within the area of best coverage it was not possible to provide any precise indication of travel direction. We are disposed to accept that Mr Fee has correctly identified the limitations that apply to the cell site analysis. As he has acknowledged, however, it does provide a general indication of the movements of the users of the telephones. If the appellants followed a different pattern of movements on the day in question, it was open to them to give evidence about those movements and to explain where they had been at the critical time in relation to the shooting. Their failure to do so, combined with the general indication that the cell site analysis provided, constituted strong evidence against them that their movements were as indicated by that analysis. In Mr McCartan’s case, his inquiry of the interviewing police officers as to how precisely he could be tied down to a particular area was also, in our judgement, extremely telling.'

The comments of the Appeal Court in para [38] suggests the appellants' own lack of self-preservation to state what their mobile telephones were doing and the reasons for going in a direction following the line of Masts used for handling calls, undermined the cell site analysis element of their appeal.

Cell Site Analysis (CSA) Images Part 2

Cell Site Analysis (CSA) Images Part 2
.

It may interest those reading the discussions that I post that Cell Site Analysis (CSA) results from terrain and clutter analysis and radio test measurements can be defined in many different ways that can demonstrate particular elements of importance to a case.
.

Image 5

.
First we need to model (Image 5) the landscape that represents the geographical area and natural and manmade phenomenon in the surrounding area. In this case the scene of crime is close to a crossroads in the middle of small urban town.
.
For the sake of comfort, juries rarely understand radio coverage that is verbally discussed but respond much better to discussion revolving around a visual aid presentation.
.

Image 6

.
In this particular case I want to show the jury that two microcells* were used and each microcell first needs to be defined (Image 6) to the jury so they have it clearly in their minds the origin and direction of the radio coverage that forms part of the discussion.
.
In the first posting below (Cell Site Analysis (CSA) Images) coverage maps were shown defining large cell/macrocell coverage. Here, it is possible to refine and finesse coverage to a specific area with microcell coverage. Importantly, it is a really good idea to make sure the first image the jury sees represents the first radio coverage that a particular mobile phone has used that you want to talk about.
.

Image 7

.

The second microcell coverage (Image 7) should also be defined and distinguished. It's always best to remember with microcell coverage radio path is shaped in the same way as the High Street. Microcells don't go around corners.

.

Image 8

.

Finally the culmination of the presentation defines how the coverage from both microcells blend (Image 8 ) at particular points along the radio path.
.
*Remember that mobile telephones need to be encouraged to use microcell coverage and the microcell location, coverage boundary, speed at which a mobile phone is moving and cell reselection cause system challenges that required the use of a new criterion that was introduced into the GSM Phase 2 Standards in 1996. Do you know what that criterion is called and how it works?
.

Lastly, having mentioned microcell and large cell, the image below (Image 9) represents a visual indication about very important technical aspects concerning radio coverage and the layers depicted are often referred to in evidence. Indeed, if you care to read some of the Mobile Telephone Case Law you can find Appeal Courts referring to the importance of comprehending how far coverage extends.
.

Image 9

More on Cell Site Analysis: http://cellsiteanalysis.blogspot.com

Cell Site Analysis (CSA) Images

Cell Site Analysis (CSA) Images
.
Cell Site Analysis (CSA) has had a good deal of airing recently here on the forum, so I thought you might like to see images from the work that I get involved.
.

Image 1

.
Image 1 is one slide from the training course material to introduce students to CSA when starting out discussing radio test measurements. It should be noted that this image represents less than 1% of all data acquired during radio test measurements.
.

Image 2

.

I thought it would be useful to include this Terrain and Clutter Map (Image 2) as I use this software to assist me in complex cases. Terrain and Clutter are discussed during training and as it was a topic of the discussion about UK Criminal Evidence Delays I thought it would be helpful to let forum members see that I am not referring to theoretical matters, terrain and clutter analysis actually takes place.

.

UK Criminal Evidence Delays: http://www.forensicfocus.com/index.php?name=Forums&file=viewtopic&t=3961

.

Image 3

.

It is essential to understand, when conducting radio test measurements, that just because radio signals can travel some distance from a particular Mast (Image 3) that coverage should not be dismissed or excluded. Operators set threshold limits, hard limits and boundary limits. It does not follow that just because a mobile is in the Green area shown in the Single Cell Prediction Map that the mobile will be excluded from using that coverage.

.

Do you remember the discussion that I put up here about fringe coverage?: http://trewmte.blogspot.com/2008/11/mobile-phones-and-fringe-coverage.html
.

Image 4

.

Best serving coverage is often posed as the deal-clincher to suggest the mobile phone was most likely or consistent with being at a particular location. There can be numerous points that could (and I say 'could' advisedly) point to best server coverage being used but rarely does it come up in evidence because the radio content in evidence rarely gets disclosed these days.

.

It is possible with best serving coverage that it can induce a negative outcome that may prevent calls taking place, so it is always important to see the other side of the coin, so to speak:
.
- http://trewmte.blogspot.com/2007/02/gsm-radio-test-measurements-non.html
- http://trewmte.blogspot.com/2007/01/gsm-radio-test-measurements.html
.

I hope the above provides a further illustration of how smart and intelligent a science Cell Site Analysis really is and that by not applying it properly and dumbing down this art of this forensic science:

.

- is not only a great loss to the law of evidence

- it reduces the examiner's/expert's knowledge and understanding about the subject with which they are dealing - mobile telephone evidence.

More on Cell Site Analysis: http://cellsiteanalysis.blogspot.com

Cell Site Analysis

Cell Site Analysis

IN HER MAJESTY'S COURT OF APPEAL IN NORTHERN IRELAND

Neutral Citation no. [2008] NICA 5

THE QUEEN v RICHARD DAVID McCARTAN and BARRY DAVID SKINNER.

Appeal Court: Kerr LCJ, Campbell LJ and Morgan J

http://www.courtsni.gov.uk/NR/rdonlyres/4F39A7FC-5350-4E4B-BB76-FA8DC4BA08D6/0/j_j_KER7057Final.htm


It is not proven with cell site analysis that evidence obtained relating to mobile call records, the Masts and their details associated with handling the calls and conducting radio test surveys combined together form a precise indication of the geographical location of a mobile telephone at the material time. Therefore, it is unlikely an alleged opinion that it is consistent to place a mobile telephone at a particular location holds weight. That cell site analysis might generally indicate the possible movement of a mobile telephone in relation to Masts that it used and no more.

Whilst the Appeal Case for the appellants (McCartan and Skinner) did not succeed it was not because cell site analysis was able to pinpoint the location of the appellants' mobile telephones, which it is unable to do, but the appellants' failure to identity what was happening with their mobile telephones at the material times. The following commentary from this Appeal Case is worth reading.

'The cell site analysis

[37] An expert in this field, David Sanderson, gave evidence, submitted a report on the subject and made a Power Point presentation to the court. Mr Fee suggested that Mr Sanderson’s evidence established that (a) call mapping was carried out in respect of telephone 008 (attributed to Mr McCartan) and telephone 301 (attributed to Mr Skinner); (b) call mapping provides an approximate indication of where a mobile phone was when a call was made; (c) call mapping is used primarily to show the likely movement of a cellular phone with a general indication of location; (d) the cellular phone may be anywhere within the best serving coverage of the sector; (e) there is boundary overlap between sectors served by different masts; (f) the extent of the best serving coverage sector is unknown; (g) the indication of movement of the person using the telephone is no more than consistent with a suggested pattern of progress – it cannot establish positively that the user of the telephone in fact moved in the mooted direction; (h) calls 15, 16 and 17 from 008 at 20.53: 20.55: 20.55 were made when the telephone was not in the vicinity of Euston Street.

[38] On the basis of this evidence Mr Fee argued that the cell site analysis did no more than provide a very imprecise indication of general movements. In the absence of a capacity to identify a precise location of the telephone within the area of best coverage it was not possible to provide any precise indication of travel direction. We are disposed to accept that Mr Fee has correctly identified the limitations that apply to the cell site analysis. As he has acknowledged, however, it does provide a general indication of the movements of the users of the telephones. If the appellants followed a different pattern of movements on the day in question, it was open to them to give evidence about those movements and to explain where they had been at the critical time in relation to the shooting. Their failure to do so, combined with the general indication that the cell site analysis provided, constituted strong evidence against them that their movements were as indicated by that analysis. In Mr McCartan’s case, his inquiry of the interviewing police officers as to how precisely he could be tied down to a particular area was also, in our judgement, extremely telling.'

The comments of the Appeal Court in para [38] suggests the appellants' own lack of self-preservation to state what their mobile telephones were doing and the reasons for going in a direction following the line of Masts used for handling calls, undermined the cell site analysis element of their appeal.