911 Call location accuracy

John Navas <[email protected]> wrote in
news:[email protected]:

> On Mon, 30 Apr 2007 16:07:19 -0500, Dennis Ferguson
> <[email protected]> wrote in
> <[email protected]>:
>
>>On 2007-04-30, John Navas <[email protected]> wrote:
>
>>> As I wrote, read up on it. Also on sector antennas. Likewise position
>>> mapping.
>>
>>Exactly. Like I said, crap.
>
> In fact the position accuracy of TruePosition U-TDOA (as used by
> AT&T/Cingular) with two receivers and reception angle is good, on par
> with accuracy with three receivers (where angle data isn't needed).
> Angle data is what makes the difference.
>
>>Of course A-GPS systems can do this too,
>>and the measurements are just as crappy. They just don't need to do
>>it as often.
>
> A-GPS depends on reception of GPS signals by the handset, which is a
> problem in many locations (urban canyons, under tree cover, indoors,
> etc.). Because of this serious weakness, hybrid A-GPS systems (e.g.,
> SnapTrack) augment GPS, using Enhanced Cell-ID with CDMA200 that's
> relatively crude as compared to U-TDOA with GSM.
>
>>So which A-GPS have you seen which doesn't work indoors?
>
> All of them. A-GPS requires GPS signals to work. Without such signals,
> accuracy depends on how much the handset has moved since the last
> position fix and on what other location data is available.
>
>>I didn't suggest any level of accuracy and reliability other than it
>>is at least as good as U-TDOA. Good luck proving otherwise.
>
> Enhanced Cell-ID has an accuracy of only 75-500 meters, far less
> accurate than U-TDOA as used in TruePosition U-TDOA.
>

Citation, Zippy?

---

› See More: 911 Call location accuracy

Dennis Ferguson wrote:

> I do notice we've moved well beyond "doesn't work indoors". Keep
> reading and you'll get up to speed.

LOL, I'm sure that he's been up to speed for a while, and that he fully
understands the advantages of the hybrid system. It's not like all these
European carriers are rushing to implement these systems without knowing
that TDOA systems aren't sufficiently accurate to make a compelling case
for LBS systems.

TDOA was implemented because it was cheap, didn't require new handsets,
and was sufficient to meet the E-911 requirement by the FCC deadline,
period. Cingular knew that in order to sell LBS systems to businesses
that they'd have to deploy a hybrid system eventually, just as they knew
that they'd have to deploy 3G data eventually.

If he really doesn't understand the technology, there are plenty of
resources for him to read.

He can start with
"http://lbs.gpsworld.com/gpslbs/article/articleDetail.jsp?id=308238"
though it gets pretty technical.

On Mon, 30 Apr 2007 18:41:00 -0500, Dennis Ferguson
<[email protected]> wrote in
<[email protected]>:

>On 2007-04-30, John Navas <[email protected]> wrote:

>> In fact the position accuracy of TruePosition U-TDOA (as used by
>> AT&T/Cingular) with two receivers and reception angle is good, on par
>> with accuracy with three receivers (where angle data isn't needed).
>> Angle data is what makes the difference.
>
>If you say so. Hybrid A-GPS doesn't need the angle to handle the
>two tower case (it can be done just with timing information), only
>the one tower case.

Proof?

>This would imply you've seen non-hybrid A-GPS implemented on some
>cell phone (since that's what you said). Which one?

I'm not at liberty to say.

>> Enhanced Cell-ID has an accuracy of only 75-500 meters, far less
>> accurate than U-TDOA as used in TruePosition U-TDOA.
>
>Proof?

See citation in my prior post.

--
Best regards, FAQ FOR CINGULAR WIRELESS:
John Navas <http://en.wikibooks.org/wiki/Cingular_Wireless_FAQ>

On Mon, 30 Apr 2007 16:43:17 -0700, SMS <[email protected]>
wrote in <[email protected]>:

>Dennis Ferguson wrote:
>
>> I do notice we've moved well beyond "doesn't work indoors". Keep
>> reading and you'll get up to speed.
>
>LOL, I'm sure that he's been up to speed for a while, and that he fully
>understands the advantages of the hybrid system. It's not like all these
>European carriers are rushing to implement these systems without knowing
>that TDOA systems aren't sufficiently accurate to make a compelling case
>for LBS systems.
>
>TDOA was implemented because it was cheap, didn't require new handsets,
>and was sufficient to meet the E-911 requirement by the FCC deadline,
>period. Cingular knew that in order to sell LBS systems to businesses
>that they'd have to deploy a hybrid system eventually, just as they knew
>that they'd have to deploy 3G data eventually.

Proof? Or yet another made up claim?

--
Best regards, FAQ FOR CINGULAR WIRELESS:
John Navas <http://en.wikibooks.org/wiki/Cingular_Wireless_FAQ>

John Navas <[email protected]> wrote in
news:[email protected]:

> On Mon, 30 Apr 2007 18:41:00 -0500, Dennis Ferguson
> <[email protected]> wrote in
> <[email protected]>:
>

>
>>This would imply you've seen non-hybrid A-GPS implemented on some
>>cell phone (since that's what you said). Which one?
>
> I'm not at liberty to say.


Bull****! You just got caught with your pants down again, Novice.
Translation- you were lying once again. There is no such phone on american
soil, you pinhead.

On 2007-04-30, John Navas <[email protected]> wrote:
> On Mon, 30 Apr 2007 18:18:23 -0500, Dennis Ferguson wrote:
>> http://www.snaptrack.com/pdf/ion2002...ermination.pdf
>> http://www.snaptrack.com/pdf/ion2002...ybrid_agps.pdf
>
> What matters, of course, is what's actually in the field, and how well
> it performs in the real world.

Which is exactly what is described in those papers. Let me get
a useful quote out:

Terrestrial Measurements

In addition to the efficient use of GPS signals, strong and
weak, the PDE also makes use of a variety of terrestrial
measurements. Within the CDMA network, these
measurements include coarse and fine pilot phase
measurements from legacy and gpsOneTM enabled
handsets, respectively. The resolution (precision) of
coarse pilot measurements is on the order of 1 CDMA
chip (~240 m), while the resolution of the fine pilot phase
measurements is 1/16 of a CDMA chip (~15 m). On the
reverse link, Round Trip Delay (RTD) measurements are
available for both legacy and gpsOneTM enabled handsets
via the J-STD-036 interface in the control plane
architecture.

>http://www.cdmatech.com/docs_details/tech_demos/demos/gpsone_hybrid.html>

Got it. You took one line out of a non-technical cartoon presentation
and assumed that is telling you something about how it works.

>>I do notice we've moved well beyond "doesn't work indoors".
>
> On the contrary -- A-GPS simply doesn't work without GPS signals (e.g.,
> in urban canyons, under tree cover, _indoors_) -- kindly refrain from
> trying to put words in my mouth.
>
> Hybrid A-GPS systems are a result of scrambling to overcome the serious
> limitations of A-GPS-based positioning alone, which doesn't work well or
> at all in many environments.

Actually, the papers are describing what was deployed 5 years ago. What
positioning technology was Cingular using then?

However, I give up. I think it is pretty clear by now what is factual
and what is being made up.

Dennis Ferguson

Dennis Ferguson wrote:

> However, I give up. I think it is pretty clear by now what is factual
> and what is being made up.

Yet rather than kill-file Navas like most of us, you respond to his
fabrications.

Wait, maybe the accurate system that Cingular doesn't know they have is
somehow related to Extended Range GSM. It only exists in the mind of one
person in the world. Everyone else has to deal with life in the real world.

SMS <[email protected]> wrote in
news:[email protected]:

> Dennis Ferguson wrote:
>
>> However, I give up. I think it is pretty clear by now what is
>> factual and what is being made up.
>
> Yet rather than kill-file Navas like most of us, you respond to his
> fabrications.
>


And if he didn't, many unsuspecting readers would believe Johhny's
fabrications as truth. There is more damage caused there than the waste of
bandwidth involved in screening his crap. The fact that you respond to his
posts after they have been replied to (as you do in many instances) gives
you little room to criticize others.

Putting your head in the sand like an ostrich is not the solution.

On Mon, 30 Apr 2007 19:10:23 -0500, Dennis Ferguson
<[email protected]> wrote in
<[email protected]>:

>On 2007-04-30, John Navas <[email protected]> wrote:
>> On Mon, 30 Apr 2007 18:18:23 -0500, Dennis Ferguson wrote:
>>> http://www.snaptrack.com/pdf/ion2002...ermination.pdf
>>> http://www.snaptrack.com/pdf/ion2002...ybrid_agps.pdf
>>
>> What matters, of course, is what's actually in the field, and how well
>> it performs in the real world.
>
>Which is exactly what is described in those papers.

Those papers describe what _can_ be done, not what _has_ been done, or
even what _is_ being done, in the field.

>Got it. You took one line out of a non-technical cartoon presentation
>and assumed that is telling you something about how it works.

No.

>Actually, the papers are describing what was deployed 5 years ago. What
>positioning technology was Cingular using then?

CDMA2000 went for A-GPS, despite its much higher cost and lengthier
deployment, not because it was more accurate (and not because of any LBS
expectations), but because it was the most expedient way, given the
limitations of CDMA2000 gear in the field and in deployment, to comply
with the E911 mandate, albeit with waivers.

GSM similarly went with E-OTD because it was the most expedient way,
given the GSM gear in the field and in deployment, to comply with the
E911 mandate.

In practice both solutions proved to fall short of initial claims, with
GPS signal limitations initially forcing CDMA2000 into a hybrid (kludge)
cell-based approach, and E-OTD limitations forcing GSM into more
sophisticated TruePosition U-TDOA. Development has of course continued
in all areas, blurring the differences.

>However, I give up. I think it is pretty clear by now what is factual
>and what is being made up.

I generally agree, except the real issues here are out-of-control
advocacy and rewriting of history, past, present, and future.

In practice, neither system is really better than the other,
notwithstanding the claims of proponents. They both do a pretty good
job of meeting the E911 mandate, albeit with delays and limitations.
Claiming that one is better than the other is just as silly as claiming
that CDMA2000 is better than GSM, or vice versa, because from the user
perspective, both are capable of very good performance, and differences
in deployment are what matter, not differences in technology.

--
Best regards, FAQ FOR CINGULAR WIRELESS:
John Navas <http://en.wikibooks.org/wiki/Cingular_Wireless_FAQ>

On Mon, 30 Apr 2007 17:40:22 -0700, SMS <[email protected]>
wrote in <[email protected]>:

>Dennis Ferguson wrote:
>
>> However, I give up. I think it is pretty clear by now what is factual
>> and what is being made up.
>
>Yet rather than kill-file Navas like most of us, you respond to his
>fabrications.
>
>Wait, maybe the accurate system that Cingular doesn't know they have is
>somehow related to Extended Range GSM. It only exists in the mind of one
>person in the world. Everyone else has to deal with life in the real world.

By your pure ad hominems shall we know ye.

--
Best regards,
John Navas <http:/navasgroup.com>

'Those who have evidence will present their evidence,
whereas those who do not have evidence will attack the man.'

Scott wrote:

>> Yet rather than kill-file Navas like most of us, you respond to his
>> fabrications.
>>
>
>
> And if he didn't, many unsuspecting readers would believe Johhny's
> fabrications as truth.

There isn't some vast group of readers that automatically believe
anything that these Usenet trolls make up.

Just how many unsuspecting readers out there don't understand that their
exists a group of Usenet posters like Navas whose sole mission in life
is to shill, to be as obnoxious as possible in the process, and to never
provide citations for anything.

> Putting your head in the sand like an ostrich is not the solution.

Ignoring trolls _is_ actually a good solution. Eventually the rolls get
tired of not evoking a response and go away. It worked with Jim, and it
can work with John.


[Copied to alt.cellular.attws. Please post all alt.cellular.cingular
posts to alt.cellular.attws as well. The Cingular name is going away,
and alt.cellular.attws is the proper venue for posts regarding AT&T's
Wireless Service.]

John Navas <[email protected]> wrote in
news:[email protected]:


>
> By your pure ad hominems shall we know ye.
>

And by your lack of facts and abundance of obvious lies shall we know ye...

On Mon, 30 Apr 2007 18:12:03 -0700, SMS <[email protected]>
wrote in <[email protected]>:

>Just how many unsuspecting readers out there don't understand that their
>exists a group of Usenet posters like Navas whose sole mission in life
>is to shill, to be as obnoxious as possible in the process, and to never
>provide citations for anything.

Pot ... kettle ... black.

In fact I post numerous citations, whereas you post almost none.

--
Best regards,
John Navas <http:/navasgroup.com>

"A little learning is a dangerous thing." [Alexander Pope]
"It is better to sit in silence and appear ignorant,
than to open your mouth and remove all doubt." [Mark Twain]

SMS <[email protected]> wrote in news:463693e4$0$27221
[email protected]:

> Scott wrote:
>
>>> Yet rather than kill-file Navas like most of us, you respond to his
>>> fabrications.
>>>
>>
>>
>> And if he didn't, many unsuspecting readers would believe Johhny's
>> fabrications as truth.
>
> There isn't some vast group of readers that automatically believe
> anything that these Usenet trolls make up.
>
> Just how many unsuspecting readers out there don't understand that their
> exists a group of Usenet posters like Navas whose sole mission in life
> is to shill, to be as obnoxious as possible in the process, and to never
> provide citations for anything.

You better check the archives- he's sucked in more than his fair share and
on subjects that could cause heartburn for anyone taking his "advice".

The number of readers is not important- one believing his crap is too many.

>
>> Putting your head in the sand like an ostrich is not the solution.
>
> Ignoring trolls _is_ actually a good solution. Eventually the rolls get
> tired of not evoking a response and go away. It worked with Jim, and it
> can work with John.
>

But you don't ignore him, which was a point I made in the last post that
you conveniently cut out. Again- you have no room to criticize anyone, as
you reply to his posts more often than most here, albeit in response to a
response.

>
> [Copied to alt.cellular.attws. Please post all alt.cellular.cingular
> posts to alt.cellular.attws as well. The Cingular name is going away,
> and alt.cellular.attws is the proper venue for posts regarding AT&T's
> Wireless Service.]
>

And give this up- you are the only one crossposting and it makes some
threads unreadable. Obviously, nobody is interested at this time to switch
groups. The time to do this would be when the Cingular name actually
disappears.