ok sot the drawing disappeared!!! see attached for it From: hellenmasita@hotmail.com To: skunkworks@lists.my.co.ke Date: Tue, 23 Aug 2011 08:37:37 +0300 Subject: Re: [Skunkworks] Discussion: Triangulation in GSM @steve, i agree, using just the timing advance and serving Cell may give to wide an area for estimation, but that is why i said we get some readings for 6 of the strongest neighboring cells that the mobile station can sense!!!! option 1 so far, this is what i am considering; attenuation on the air interface can be estimated using engineering models, depending on whether it is a rural or urban site, given the attenuation, can we not estimate the distance from the other cells and use this to narrow the possible location.the challenge with this idea is that most engineering models come inbuilt into specific expensive software and might not flexible to be used as stand alone option 2, About the vectors, even without the attenuation model, give that i can get the coordinates of all the sites and azimuths of the sectors(where they are pointing) of the serving cell, how about if we draw vectors and check the points of intersection and areas falling within this points. option 3 use both of the above together excuse my drawing, but see what i mean, if sites B to F are the six strongest neighbors, we could use them to narrow down the location.....
Date: Thu, 13 Oct 2011 18:21:24 +0300 From: steve@sobbayi.com To: skunkworks@lists.my.co.ke Subject: Re: [Skunkworks] Discussion: Triangulation in GSM
Guys don't worry about about the complexities, Its easy once you get used to the laws and properties of numbers and shapes
----- "Timothy Mutugi" <timothymutugi@gmail.com> wrote:
....ok @washi, it is just that I have been called a n00b before and so I am feeling kinda shy and embarrassed and "shame-on-me" to as what this triangulation thing is all about...
....I did home economics and so perhaps the only thing I can triangulate is a samosa because it looks triangular...
On 8/22/11, Odhiambo Washington <odhiambo@gmail.com> wrote:
LOL!!!!
@Mutugi - if you have no idea, then it's time you shed off your *skunk* skin<LOL>
Anyway, the way @Obbayi, put it out, you surely need to have been present in a classroom where they taught engineering mathematics.
On Mon, Aug 22, 2011 at 15:40, Timothy Mutugi <timothymutugi@gmail.com>wrote:
?
I have no idea of what is being discussed here, but it sounds very skunk-like and highly technical...good post, keep it up:-)
Timo.
On 10/13/11, Steve Obbayi <steve@sobbayi.com> wrote:
There are two ways of doing this. Although I am not an expert on GSM and BTS etc, The solution here is common to that which I would commonly use in 2D/3D graphics programming. Hope you understand a bit of linear algebra and geometric transformations.
Nways, here goes
1. The direction doesn't matter, If you can get readings of three or more points as zero vectors then you can compute the resulting vectors of the location of the device. Using two initial zero vectors wont work as your computed results will intersect at two possible vectors.
which brings me to the second method
2. Using your trigonometry skills, you can calculate the the angle between the two fixed known points of the BTS and the two possible third points of the resulting two triads based on the distance of at least two BTS stations. This should get you good reading.
Steve
----- "Kinuthia Ngugi" <kinuthia.ngugi@gmail.com> wrote:
Am afraid in GSM, the TA and serving cell is as narrow as it can get. You can not hope to have more than half a kilometer precision. Normaly, timing advance goes in units of 550m, so TA 0 means 550m form the BTS, TA 1 means 1..1KM, so and on. Then there is the issue of how wide a cell's coverage is; you could be having a BTS on a hill with an antenna that has a 90deg beamwidth in the far field....that could mean a span of like 10km across that field, so even if the TA tells you are 3km from the BTS, but in which direction? North or South or East? such are the challenges. All the best though.
On Mon, Aug 22, 2011 at 10:11 AM, hellen masita < hellenmasita@hotmail.com > wrote:
Hi skunks/skunkettes,
in line with an earlier discussion on this being a technical forum...
May i call upon your help without monetary gains taking an upper hand???? please :)
i want to try and create an application for triangulating a mobile phone. i am at a loss on where to start....really!!! so i throw it to the floor.
******************* In a GSM network with than one vendor a proprietary software is normally supplied to handle their equipment including the BTS.
Mobile phones however send Measurement reports which are standardized.
these reports contain the following,
1. signal level of 6 best neignbours
2. signal quality\level of serving cell 3. the BTS can determine the Timing Advance of the Mobile(The distance (usually a range) the mobile is from the bts) as well as serving cell (Sector)
Now, with just the Timing Advance (TA) and Serving cell , i can tell the general direction of a user. however i would like to use the other measurements to narrow down the location
*************************
The significance of this is that it a network can track a phone that does not have a GPS. it would make phone thefts less bothersome among things.
If guys discuss it for a bit, i'm sure i'll find my footing,
regards,
Hellen
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