On 08/02/2024 16:48, David Woolley wrote:
> On 06/02/2024 18:34, Woody wrote:
>> because 5G (and I would expect 4G as well) use GPS the masts are being
>> used to track people
>
> They are regularly used, after the fact, to track people suspected of
> crimes, down to the cell level, and I believe even 2G used round trip
> time of flight information, which can be used to get higher resolution
> information, although I'm not sure if that is routinely logged.  At one
> time you could register phones with services that used that time of
> flight information for medium resolution tracking.
>

2g uses "round trip time" in order to send the correct timing advance
signal to the handset.

Obviously it would then know how far the MS was from the BTS, if it was
interested, but not in which direction

On 08/02/2024 20:19, David Woolley wrote:
> On 08/02/2024 17:46, Abandoned Trolley wrote:
>> 2g used "round trip time" in order to send the correct timing advance
>> signal to the handset.
>>
>> Obviously it would then know how far the MS was from the BTS, if it
>> was interested, but not in which direction
>
> If you have sectored antennas, you also have direction, which I think
> may be as far as the public services went, but I believe that the system
> could be made to measure distance from multiple towers, which allows a
> 2D solution.

If the site is sectored then you would normally know which 120 degree
sector the MS is attached to, which might not provide the accuracy which
you "need"

If its an omni site then you have no chance

Some low capacity BTS sites which appear to be sectored are in fact
quasi-omni

On 08/02/2024 20:25, David Woolley wrote:
> On 08/02/2024 20:19, David Woolley wrote:
>> the system could be made to measure distance from multiple towers,
>> which allows a 2D solution
>
>

> <https://wrongfulconvictionsblog.org/2012/06/01/cell-tower-triangulation-how-it-works/>.

"The post makes the point that data from a single cell tower is
essentially worthless in trying to place someone in a particular
location. The best you can expect is a band within a 120° “pie wedge”
from the cell tower."

Abandoned Trolley <fred@fred-smith.co.uk> writes:

> On 08/02/2024 20:25, David Woolley wrote:
>> On 08/02/2024 20:19, David Woolley wrote:
>>> the system could be made to measure distance from multiple towers,
>>> which allows a 2D solution
>>
>
>
>> <https://wrongfulconvictionsblog.org/2012/06/01/cell-tower-triangulation-how-it-works/>.
>
>
>
> "The post makes the point that data from a single cell tower is
> essentially worthless in trying to place someone in a particular
> location. The best you can expect is a band within a 120° “pie wedge”
> from the cell tower."

But if the objective is not to know where the person is, but to know
where the cell (tower) is, then the person can move and make another
observation creating a triangle.

On 14:17 8 Feb 2024, Richmond said:
> Woody <harrogate3@ntlworld.com> writes:
>> On Thu 08/02/2024 12:34, Richmond wrote:
>>> Pamela <pamela.private.mailbox@gmail.com> writes:
>>>> On 20:13 6 Feb 2024, Richmond said:
>>>>> Woody <harrogate3@ntlworld.com> writes:
>>>>>> On Tue 06/02/2024 17:42, Richmond wrote:
>>>>>>> Abandoned Trolley <fred@fred-smith.co.uk> writes:
>>>>>>>> On 06/02/2024 16:36, Richmond wrote:
>>>>>>>>> Abandoned Trolley <fred@fred-smith.co.uk> writes:
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> Whats the mystery ?
>>>>>>>>>>>>
>>>>>>>>>>>> In urban areas, "Antenna Support Structures" are rarely
>>>>>>>>>>>> going to be towers. The map (NCI) shows them as towers.
>>>>>>>>>>>> But the main mystery is where they are.
>>>>>>>>>>
>>>>>>>>>> So ... it shows the locations, but you are unable to identify
>>>>>>>>>> them ?
>>>>>>>>>>
>>>>>>>>>> Whats the actual problem ? As I said, the two apps don't
>>>>>>>>>> agree,
>>>>>>>>> and cell 'towers' or 'cells' vanish from the map, or move.
>>>>>>>>
>>>>>>>> Theres a number of reasons for them apparently disappearing,
>>>>>>>> especially if you are driving around in the area.
>>>>>>>>
>>>>>>>> If the sites are sectorised theres no need for them to be
>>>>>>> symmetrical I am not driving. One cell in particular vanishes
>>>>>>> when I walk towards it. If I am walking towards it then I ought
>>>>>>> to be staying in the sector. I have my doubts about whether it
>>>>>>> exists as it appears to be in someone's garden.
>>>>>>>
>>>>>> Q1: how do you know the cell mast/tower is (a) used by your SP
>>>>>> and/or (b) your phone is registered on that site?
>>>>>
>>>>> The app (NCI) shows a line going from me to the cell. I suppose
>>>>> that is what it is meant to indicate. If I switch between 2G, 3G,
>>>>> 4G it shows connections to different cells. If I walk from the
>>>>> front of the house to the back it switches between a cell to the
>>>>> south and a cell to the north.
>>>>>
>>>>>>
>>>>>> Q2: cell sites are pretty well never built in people's gardens -
>>>>>> in fields, on local authority property, on the top large
>>>>>> buildings yes - but NEVER in Joe Public's back garden.
>>>>>
>>>>> Yes, so why is it showing a cell there? If it was an error in the
>>>>> data it wouldn't vanish, so I suspect it was working something out
>>>>> based on the signals it was getting.
>>>>>
>>>>>>
>>>>>> When you are close to site - even if it is sectored - because of
>>>>>> signal strength you could be attached to any sector on that mast.
>>>>>> When you go away from it you will find out simply by whether your
>>>>>> phone continues to work or not. What is more the antennae on most
>>>>>> masts have built-in down-tilt, that is if the antenna is upright
>>>>>> the signal may be being projected with a downwards tilt of 5, 10
>>>>>> or even 15 degrees to stop the signal getting too far. Sometimes
>>>>>> you might even see an antenna tilted backwards to throw the
>>>>>> signal further than normal if required.
>>>>>>
>>>>>> Radio transmission can be magic and/or a black art even to those
>>>>>> of us who have spent a lifetime working in the industry!
>>>>>
>>>>> What information can the phone get from the cell? can it get
>>>>> distance and direction? The phone knows where I am. If it knows
>>>>> the distance to a cell it ought to be able to draw a circle and
>>>>> say the cell is somewhere on it. If I move to a different place it
>>>>> can draw another circle, and then it could deduce that the cell is
>>>>> at one of two points where the circles intersect. (Unless I walk
>>>>> directly toward or away, in which case the circles won't
>>>>> intersect).
>>>>
>>>> Based on a discussion in this group, smartphone apps are not able
>>>> to reliably determine which tower the phone is connected to.
>>>>
>>>> "App to show connected cell tower" (19 Nov 2021) See
>>>> Message-ID: <XnsADE721E6729537B93@144.76.35.252>
>>>>
>>>> Also .. like you I found Network Cell Info's and OpenSignal's apps
>>>> did not always agree. ISTR the biggest discrepancy was related to
>>>> masts filling in a small area.
>>>
>>> Thanks. It looks like an intractable problem. I found this site:
>>> https://opencellid.org/ But when I put in the details of my current
>>> serving cell from NCI it showed me a location about 150 miles away!
>>
>>
>> And the NCI app would be.....?
>
> Network Cell Info (Lite)

The last time I visited m2catalyst.com, I vaguely recall it said they
were no longer developing the Network Cell Info app (although I could be
mistaken).

On Thursday 8 February 2024 at 20:54:53 UTC, Abandoned Trolley wrote:
> On 08/02/2024 20:19, David Woolley wrote:
> > On 08/02/2024 17:46, Abandoned Trolley wrote:
> >> 2g used "round trip time" in order to send the correct timing advance
> >> signal to the handset.
> >>
> >> Obviously it would then know how far the MS was from the BTS, if it
> >> was interested, but not in which direction
> >
> > If you have sectored antennas, you also have direction, which I think
> > may be as far as the public services went, but I believe that the system
> > could be made to measure distance from multiple towers, which allows a
> > 2D solution.
> If the site is sectored then you would normally know which 120 degree
> sector the MS is attached to, which might not provide the accuracy which
> you "need"
>
> If its an omni site then you have no chance
>
> Some low capacity BTS sites which appear to be sectored are in fact
> quasi-omni
This was how Voda did it originally in 1G and that and an inability to work with voice activated transmit in the mobile led to frequent dropped connections compared to BTCellnet (omni directional bases and call not dropped if handset doesn't transmit for a second or two.

On 08/02/2024 16:48, David Woolley wrote:
> There is, of course, a lot of misinformation about GPS.  Even TV
> forensics programmes claim the the satellites are tracking you, when, in
> fact, the radio transmission is one way: sky to ground.

I completely lost any faith in anything Stephen Fry says when he
explained on a radio or TV programme that GPS worked by the satellite
receiving a signal from your phone or other GPS unit. He obviously had
not idea what he was talking about but spoke as if he did.

JMB99 <mb@nospam.net> writes:

> On 08/02/2024 16:48, David Woolley wrote:
>> There is, of course, a lot of misinformation about GPS.  Even TV
>> forensics programmes claim the the satellites are tracking you,
>> when, in fact, the radio transmission is one way: sky to ground.
>
>
>
> I completely lost any faith in anything Stephen Fry says when he
> explained on a radio or TV programme that GPS worked by the satellite
> receiving a signal from your phone or other GPS unit. He obviously
> had not idea what he was talking about but spoke as if he did.

If a phone uses GPS to determine its own whereabouts, and then sends
that information to Google or Apple, then, indirectly, the satellite has
been used for tracking. Although WiFi hot spots could be used in the same
way instead of satellites.