Re: simple GPS lat/lon display?

D wrote:
> On Fri, 04 Apr 2008 21:12:28 -0400, "Richard B. Gilbert"
> <rgilbert88@comcast.net> wrote:
>
>
>>Roger 2008 wrote:
>>
>>>"Gordon Burditt" <gordonb.sh6xy@burditt.org> wrote in message
>>>news:XrOdnYKg7an-52vanZ2dnUVZ_vOlnZ2d@internetamerica...
>>>
>>>
>>>>>Please do not forget who the original poster was and his questions: He
>>>>>asked:
>>>>>"can I display my own LAT/LON values somehow without a map application ?"
>>>>
>>>>For some cell phone implementation of "GPS" (this one doesn't involve
>>>>actual satellites talking to your phone), your position coordinates
>>>>are present at the cell towers and somewhere in the offices of Big
>>>>Brother, but not on your cell phone. If a map application can get
>>>>your position at all, it has to ask your cell provider to send it,
>>>>and that may cost money.
>>>
>>>
>>>Oh yeah, now that you mention it. My first camera phone called it GPS but
>>>when you read further about it, it was just using cell phone towers.
>>>
>>>BTW I have met a person with an iPHONE that thinks his phone has GPS and he
>>>even showed me "Google Maps for Mobile" on it.
>>>
>>>I thought he had a messed up GPS reading because it had us way across the
>>>street and then I learned later the iPHONE uses cell phone towers for an
>>>approximate location on "Google Maps for Mobile."
>>>
>>>
>>
>>GPS, or at least the civilian version of it, is only accurate to within
>>about 300 feet or 100 meters. I once did a "site survey" using a
>>Motorola M12+T GPS timing receiver. The software I used plotted
>>something like 10,000 position readings on the map. The result was a
>>strip about 10 meters wide and 100 meters long and oriented ENE-SSW. My
>>antenna was more or less in the middle of this mess.
>>
>>The military uses a different set of signals from the same satellite and
>>gets accurracy good enough for weapons targeting. This level of GPS is
>>available only to the military and certain defense contractors. Us
>>lowly civilians can't get it.
>>
>>As far as I know, a cell phone tower has no means of determining the
>>direction your signal is coming from.
>
>
> Towers cannot tell what direction the signal is coming from, but can
> tell from relative power how far away it is, and form a circle based
> on that reading. For sake of argument, say you are 3 miles from
> tower one, and 5 miles from tower two. there are only two places you
> can be 3 milies and 5 miles from the towers. Add a third tower, and
> you only have one place you can be. That is how triangulation (hence
> the tri - three) works.
>

I suspect that this technique would yield an uncertainty of position
that is far greater than that inherent in GPS. For one thing, the
relative signal strength depends on more than distance!

Richard B. Gilbert wrote:

> D wrote:
>> On Fri, 04 Apr 2008 21:12:28 -0400, "Richard B. Gilbert"
>> <rgilbert88@comcast.net> wrote:
>>
>>>Roger 2008 wrote:
>>>
>>>>"Gordon Burditt" <gordonb.sh6xy@burditt.org> wrote in message
>>>>news:XrOdnYKg7an-52vanZ2dnUVZ_vOlnZ2d@internetamerica...
>>>>
>>>>
>>>>>>Please do not forget who the original poster was and his questions: He
>>>>>>asked:
>>>>>>"can I display my own LAT/LON values somehow without a map application ?"
>>>>>
>>>>>For some cell phone implementation of "GPS" (this one doesn't involve
>>>>>actual satellites talking to your phone), your position coordinates
>>>>>are present at the cell towers and somewhere in the offices of Big
>>>>>Brother, but not on your cell phone. If a map application can get
>>>>>your position at all, it has to ask your cell provider to send it,
>>>>>and that may cost money.
>>>>
>>>>
>>>>Oh yeah, now that you mention it. My first camera phone called it GPS but
>>>>when you read further about it, it was just using cell phone towers.
>>>>
>>>>BTW I have met a person with an iPHONE that thinks his phone has GPS and he
>>>>even showed me "Google Maps for Mobile" on it.
>>>>
>>>>I thought he had a messed up GPS reading because it had us way across the
>>>>street and then I learned later the iPHONE uses cell phone towers for an
>>>>approximate location on "Google Maps for Mobile."
>>>>
>>>>
>>>
>>>GPS, or at least the civilian version of it, is only accurate to within
>>>about 300 feet or 100 meters. I once did a "site survey" using a
>>>Motorola M12+T GPS timing receiver. The software I used plotted
>>>something like 10,000 position readings on the map. The result was a
>>>strip about 10 meters wide and 100 meters long and oriented ENE-SSW. My
>>>antenna was more or less in the middle of this mess.
>>>
>>>The military uses a different set of signals from the same satellite and
>>>gets accurracy good enough for weapons targeting. This level of GPS is
>>>available only to the military and certain defense contractors. Us
>>>lowly civilians can't get it.
>>>
>>>As far as I know, a cell phone tower has no means of determining the
>>>direction your signal is coming from.
>>
>> Towers cannot tell what direction the signal is coming from, but can
>> tell from relative power how far away it is, and form a circle based
>> on that reading. For sake of argument, say you are 3 miles from
>> tower one, and 5 miles from tower two. there are only two places you
>> can be 3 milies and 5 miles from the towers. Add a third tower, and
>> you only have one place you can be. That is how triangulation (hence
>> the tri - three) works.
>
> I suspect that this technique would yield an uncertainty of position
> that is far greater than that inherent in GPS. For one thing, the
> relative signal strength depends on more than distance!

Yes, the single tower strength method is inherently inaccurate. It is
however better than only knowing which tower a handset is using, the
least accurate, and previously the only method of locating someone
that's lost. Modern GPS/WAAS is by far the most accurate, but the other
methods do have their place as a backup when GPS is not available for
one reason or another...

--
Dutch

Roger 2008 wrote:
> "D" <noemail@respondhere.com> wrote in message
> news:f9pdv358q4d767lpi21ua63eouhaap4gqa@4ax.com...
>> On Fri, 04 Apr 2008 21:12:28 -0400, "Richard B. Gilbert"
>> <rgilbert88@comcast.net> wrote:
>>
>>> Roger 2008 wrote:
>>>> "Gordon Burditt" <gordonb.sh6xy@burditt.org> wrote in message
>>>> news:XrOdnYKg7an-52vanZ2dnUVZ_vOlnZ2d@internetamerica...
>>>>
>>>>>> Please do not forget who the original poster was and his questions:
> He
>>>>>> asked:
>>>>>> "can I display my own LAT/LON values somehow without a map application
> ?"
>>>>> For some cell phone implementation of "GPS" (this one doesn't involve
>>>>> actual satellites talking to your phone), your position coordinates
>>>>> are present at the cell towers and somewhere in the offices of Big
>>>>> Brother, but not on your cell phone. If a map application can get
>>>>> your position at all, it has to ask your cell provider to send it,
>>>>> and that may cost money.
>>>>
>>>> Oh yeah, now that you mention it. My first camera phone called it GPS
> but
>>>> when you read further about it, it was just using cell phone towers.
>>>>
>>>> BTW I have met a person with an iPHONE that thinks his phone has GPS
> and he
>>>> even showed me "Google Maps for Mobile" on it.
>>>>
>>>> I thought he had a messed up GPS reading because it had us way across
> the
>>>> street and then I learned later the iPHONE uses cell phone towers for
> an
>>>> approximate location on "Google Maps for Mobile."
>>>>
>>>>
>>> GPS, or at least the civilian version of it, is only accurate to within
>>> about 300 feet or 100 meters. I once did a "site survey" using a
>>> Motorola M12+T GPS timing receiver. The software I used plotted
>>> something like 10,000 position readings on the map. The result was a
>>> strip about 10 meters wide and 100 meters long and oriented ENE-SSW. My
>>> antenna was more or less in the middle of this mess.
>>>
>>> The military uses a different set of signals from the same satellite and
>>> gets accurracy good enough for weapons targeting. This level of GPS is
>>> available only to the military and certain defense contractors. Us
>>> lowly civilians can't get it.
>>>
>>> As far as I know, a cell phone tower has no means of determining the
>>> direction your signal is coming from.
>> Towers cannot tell what direction the signal is coming from, but can
>> tell from relative power how far away it is, and form a circle based
>> on that reading. For sake of argument, say you are 3 miles from
>> tower one, and 5 miles from tower two. there are only two places you
>> can be 3 milies and 5 miles from the towers. Add a third tower, and
>> you only have one place you can be. That is how triangulation (hence
>> the tri - three) works.
>
> With no disrespect for the poster that started this thread then how does VOR
> for airplanes work from one transmitting site?
>

Not the OP but VOR is a positioning system by design. You can establish
a LOP because your VOR receiver measures the phase difference of the 0
deg reference signal and the rotating signal from the station. That
phase difference is the radial you are on and what the VOR receiver
displays. To further enhance things they often colocate DME at the VOR
site. An additional unit in the airplane sends an interrogation to the
ground station which then replies. The airborne unit uses the transit
time to deduce its distance from the station.


> More on VOR can be found at:
> http://www.pilotfriend.com/training/...v_overview.htm
>
> But the above site doesn't come right out and say if they use more than one
> transmitting tower to get VOR to work.
>
> I have been under the assumption that since most cellphone towers have three
> elements that the cellphone knew that it was 1 of 3 directions away from the
> tower but now it seems there is nothing VOR related in cell phone towers.
>
>

"D" <noemail@respondhere.com> wrote in message
news:f9pdv358q4d767lpi21ua63eouhaap4gqa@4ax.com...
> On Fri, 04 Apr 2008 21:12:28 -0400, "Richard B. Gilbert"
> <rgilbert88@comcast.net> wrote:
>
> >Roger 2008 wrote:
> >> "Gordon Burditt" <gordonb.sh6xy@burditt.org> wrote in message
> >> news:XrOdnYKg7an-52vanZ2dnUVZ_vOlnZ2d@internetamerica...
> >>
> >>>>Please do not forget who the original poster was and his questions:
He
> >>>>asked:
> >>>>"can I display my own LAT/LON values somehow without a map application
?"
> >>>
> >>>For some cell phone implementation of "GPS" (this one doesn't involve
> >>>actual satellites talking to your phone), your position coordinates
> >>>are present at the cell towers and somewhere in the offices of Big
> >>>Brother, but not on your cell phone. If a map application can get
> >>>your position at all, it has to ask your cell provider to send it,
> >>>and that may cost money.
> >>
> >>
> >> Oh yeah, now that you mention it. My first camera phone called it GPS
but
> >> when you read further about it, it was just using cell phone towers.
> >>
> >> BTW I have met a person with an iPHONE that thinks his phone has GPS
and he
> >> even showed me "Google Maps for Mobile" on it.
> >>
> >> I thought he had a messed up GPS reading because it had us way across
the
> >> street and then I learned later the iPHONE uses cell phone towers for
an
> >> approximate location on "Google Maps for Mobile."
> >>
> >>
> >
> >GPS, or at least the civilian version of it, is only accurate to within
> >about 300 feet or 100 meters. I once did a "site survey" using a
> >Motorola M12+T GPS timing receiver. The software I used plotted
> >something like 10,000 position readings on the map. The result was a
> >strip about 10 meters wide and 100 meters long and oriented ENE-SSW. My
> >antenna was more or less in the middle of this mess.
> >
> >The military uses a different set of signals from the same satellite and
> >gets accurracy good enough for weapons targeting. This level of GPS is
> >available only to the military and certain defense contractors. Us
> >lowly civilians can't get it.
> >
> >As far as I know, a cell phone tower has no means of determining the
> >direction your signal is coming from.
>
> Towers cannot tell what direction the signal is coming from, but can
> tell from relative power how far away it is, and form a circle based
> on that reading. For sake of argument, say you are 3 miles from
> tower one, and 5 miles from tower two. there are only two places you
> can be 3 milies and 5 miles from the towers. Add a third tower, and
> you only have one place you can be. That is how triangulation (hence
> the tri - three) works.

With no disrespect for the poster that started this thread then how does VOR
for airplanes work from one transmitting site?

More on VOR can be found at:
http://www.pilotfriend.com/training/...v_overview.htm

But the above site doesn't come right out and say if they use more than one
transmitting tower to get VOR to work.

I have been under the assumption that since most cellphone towers have three
elements that the cellphone knew that it was 1 of 3 directions away from the
tower but now it seems there is nothing VOR related in cell phone towers.

On Fri, 04 Apr 2008 21:50:07 -0500, Gordon Burditt <gordonb.00byx@burditt.org> wrote:
>>GPS, or at least the civilian version of it, is only accurate to within
>>about 300 feet or 100 meters. I once did a "site survey" using a
>>Motorola M12+T GPS timing receiver. The software I used plotted
>>something like 10,000 position readings on the map. The result was a
>>strip about 10 meters wide and 100 meters long and oriented ENE-SSW. My
>>antenna was more or less in the middle of this mess.

>There's also something called Differential GPS, which uses a transmitter
>on the ground to broadcast corrections. That supposedly improves
>the reading, if and where a DGPS transmitter is available.

It was a bigger deal when consumer GPS had a built in 200' error.

I worked on a differential GPS system used by a local phone company to track
their service trucks. The error from a fixed unit was subtracted from the
mobile units to remove their error. Apparantently, the 200' error was the
same over a large region.

AZ Nomad wrote:
> I worked on a differential GPS system used by a local phone company to track
> their service trucks. The error from a fixed unit was subtracted from the
> mobile units to remove their error. Apparantently, the 200' error was the
> same over a large region.

It's surprising. For a while there was a DGPS server on the net. I was using
DGPS data from other parts of the country and getting more accurate fixes
(as compared to time-averaged position fixes).

--
$109,000,000 in income! Capitalism works GREAT for Billary...
...why does she want Marxism for us?

In article <47F6D1FC.5010200@comcast.net>,
"Richard B. Gilbert" <rgilbert88@comcast.net> wrote:

> Roger 2008 wrote:
> > "Gordon Burditt" <gordonb.sh6xy@burditt.org> wrote in message
> > news:XrOdnYKg7an-52vanZ2dnUVZ_vOlnZ2d@internetamerica...
> >
> >>>Please do not forget who the original poster was and his questions: He
> >>>asked:
> >>>"can I display my own LAT/LON values somehow without a map application ?"
> >>
> >>For some cell phone implementation of "GPS" (this one doesn't involve
> >>actual satellites talking to your phone), your position coordinates
> >>are present at the cell towers and somewhere in the offices of Big
> >>Brother, but not on your cell phone. If a map application can get
> >>your position at all, it has to ask your cell provider to send it,
> >>and that may cost money.
> >
> >
> > Oh yeah, now that you mention it. My first camera phone called it GPS but
> > when you read further about it, it was just using cell phone towers.
> >
> > BTW I have met a person with an iPHONE that thinks his phone has GPS and he
> > even showed me "Google Maps for Mobile" on it.
> >
> > I thought he had a messed up GPS reading because it had us way across the
> > street and then I learned later the iPHONE uses cell phone towers for an
> > approximate location on "Google Maps for Mobile."
> >
> >
>
> GPS, or at least the civilian version of it, is only accurate to within
> about 300 feet or 100 meters. I once did a "site survey" using a
> Motorola M12+T GPS timing receiver. The software I used plotted
> something like 10,000 position readings on the map. The result was a
> strip about 10 meters wide and 100 meters long and oriented ENE-SSW. My
> antenna was more or less in the middle of this mess.
>
> The military uses a different set of signals from the same satellite and
> gets accurracy good enough for weapons targeting. This level of GPS is
> available only to the military and certain defense contractors. Us
> lowly civilians can't get it.
>
> As far as I know, a cell phone tower has no means of determining the
> direction your signal is coming from.

It's been changed for a few years, now more like 15 meters. Clinton was
the one that changed that.

There is supposedly a new civilian GPS system in the works, one that
uses more satellites and with technolgy that allows for obstructed views.
Also supposed to be far more

--
To reply by email, remove the word "space"

> So by listening to the satellites, communication is happening.
> Thanks for nothing.

Oh give it a rest. You got it wrong, in several ways, and now you're just
flailing. See that shovel in your hand? Stop digging, ntiwit.

Kurt wrote:
> "Richard B. Gilbert" <rgilbert88@comcast.net> wrote:
>> GPS, or at least the civilian version of it, is only accurate to within
>> about 300 feet or 100 meters.
>
> It's been changed for a few years, now more like 15 meters. Clinton was
> the one that changed that.

http://www.navcen.uscg.gov/faq/gpsfaq.htm#Standard

SPS provides accuracy's of (for position, the accuracy with respect to
geographic, or geodetic coordinates of the Earth) within:
100 meters (2 drms) horizontal 156 meters (2 Sigma) vertical 300 meters
(99.99% prob.) horizontal 340 nanoseconds time (95% prob.)

--
$109,000,000 in income! Capitalism works GREAT for Billary...
...why does she want Marxism for us?

clifto wrote:
> Kurt wrote:
>
>> "Richard B. Gilbert" <rgilbert88@comcast.net> wrote:
>>
>>>GPS, or at least the civilian version of it, is only accurate to within
>>>about 300 feet or 100 meters.
>>
>>It's been changed for a few years, now more like 15 meters. Clinton was
>>the one that changed that.
>
>
> http://www.navcen.uscg.gov/faq/gpsfaq.htm#Standard
>
> SPS provides accuracy's of (for position, the accuracy with respect to
> geographic, or geodetic coordinates of the Earth) within:
> 100 meters (2 drms) horizontal 156 meters (2 Sigma) vertical 300 meters
> (99.99% prob.) horizontal 340 nanoseconds time (95% prob.)
>




"What is the status of Selective Availability (SA)?

Effective as of Midnight 01 May 2000, Selective Availability has been set to
zero."


"THE WHITE HOUSE

Office of the Press Secretary

For Immediate Release May 1, 2000

STATEMENT BY THE PRESIDENT REGARDING THE UNITED STATES' DECISION TO STOP
DEGRADING GLOBAL POSITIONING SYSTEM ACCURACY

Today, I am pleased to announce that the United States will stop the
intentional degradation of the Global Positioning System (GPS) signals
available to the public beginning at midnight tonight. We call this
degradation feature Selective Availability (SA). This will mean that
civilian users of GPS will be able to pinpoint locations up to ten times
more accurately than they do now. ..."

News wrote:
> clifto wrote:
>> Kurt wrote:
>>
>>> "Richard B. Gilbert" <rgilbert88@comcast.net> wrote:
>>>
>>>> GPS, or at least the civilian version of it, is only accurate to
>>>> within about 300 feet or 100 meters.
>>>
>>> It's been changed for a few years, now more like 15 meters. Clinton
>>> was the one that changed that.
>>
>>
>> http://www.navcen.uscg.gov/faq/gpsfaq.htm#Standard
>>
>> SPS provides accuracy's of (for position, the accuracy with respect to
>> geographic, or geodetic coordinates of the Earth) within:
>> 100 meters (2 drms) horizontal 156 meters (2 Sigma) vertical 300
>> meters (99.99% prob.) horizontal 340 nanoseconds time (95% prob.)
>>
>
>
>
>
> "What is the status of Selective Availability (SA)?
>
> Effective as of Midnight 01 May 2000, Selective Availability has been
> set to zero."
>
>
> "THE WHITE HOUSE
>
> Office of the Press Secretary
>
> For Immediate Release May 1, 2000
>
> STATEMENT BY THE PRESIDENT REGARDING THE UNITED STATES' DECISION TO STOP
> DEGRADING GLOBAL POSITIONING SYSTEM ACCURACY
>
> Today, I am pleased to announce that the United States will stop the
> intentional degradation of the Global Positioning System (GPS) signals
> available to the public beginning at midnight tonight. We call this
> degradation feature Selective Availability (SA). This will mean that
> civilian users of GPS will be able to pinpoint locations up to ten times
> more accurately than they do now. ..."
My Garmin GPS routinely gets accuracy to within 13 - 15 _feet_. A
freind with the same GPS often gets down to 6 feet, although he's on the
east coast and I'm in the upper midwest. - David

News wrote:
> clifto wrote:
>> Kurt wrote:
>>
>>> "Richard B. Gilbert" <rgilbert88@comcast.net> wrote:
>>>
>>>>GPS, or at least the civilian version of it, is only accurate to within
>>>>about 300 feet or 100 meters.
>>>
>>>It's been changed for a few years, now more like 15 meters. Clinton was
>>>the one that changed that.
>>
>>
>> http://www.navcen.uscg.gov/faq/gpsfaq.htm#Standard
>>
>> SPS provides accuracy's of (for position, the accuracy with respect to
>> geographic, or geodetic coordinates of the Earth) within:
>> 100 meters (2 drms) horizontal 156 meters (2 Sigma) vertical 300 meters
>> (99.99% prob.) horizontal 340 nanoseconds time (95% prob.)
>
> "What is the status of Selective Availability (SA)?

What does SA have to do with the 2008 accuracy specification I posted?

--
$109,000,000 in income! Capitalism works GREAT for Billary...
...why does she want Marxism for us?

David wrote:
> My Garmin GPS routinely gets accuracy to within 13 - 15 _feet_. A
> freind with the same GPS often gets down to 6 feet, although he's on the
> east coast and I'm in the upper midwest. - David

My GPS III+ does at least that well most times. Note that the government
doesn't guarantee our GPSes will always be that good.

--
$109,000,000 in income! Capitalism works GREAT for Billary...
...why does she want Marxism for us?

clifto wrote:
> News wrote:
>
>>clifto wrote:
>>
>>>Kurt wrote:
>>>
>>>
>>>>"Richard B. Gilbert" <rgilbert88@comcast.net> wrote:
>>>>
>>>>
>>>>>GPS, or at least the civilian version of it, is only accurate to within
>>>>>about 300 feet or 100 meters.
>>>>
>>>>It's been changed for a few years, now more like 15 meters. Clinton was
>>>>the one that changed that.
>>>
>>>
>>>http://www.navcen.uscg.gov/faq/gpsfaq.htm#Standard
>>>
>>>SPS provides accuracy's of (for position, the accuracy with respect to
>>>geographic, or geodetic coordinates of the Earth) within:
>>>100 meters (2 drms) horizontal 156 meters (2 Sigma) vertical 300 meters
>>>(99.99% prob.) horizontal 340 nanoseconds time (95% prob.)
>>
>>"What is the status of Selective Availability (SA)?
>
>
> What does SA have to do with the 2008 accuracy specification I posted?
>

IIRC, SA encrypted the low order bits in order to prevent GPS being used
for weapons targeting and other anti-social behavior.

Richard B. Gilbert wrote:
> clifto wrote:
>> News wrote:
>>>clifto wrote:
>>>>Kurt wrote:
>>>>>"Richard B. Gilbert" <rgilbert88@comcast.net> wrote:
>>>>>
>>>>>>GPS, or at least the civilian version of it, is only accurate to within
>>>>>>about 300 feet or 100 meters.
>>>>>
>>>>>It's been changed for a few years, now more like 15 meters. Clinton was
>>>>>the one that changed that.
>>>>
>>>>http://www.navcen.uscg.gov/faq/gpsfaq.htm#Standard
>>>>
>>>>SPS provides accuracy's of (for position, the accuracy with respect to
>>>>geographic, or geodetic coordinates of the Earth) within:
>>>>100 meters (2 drms) horizontal 156 meters (2 Sigma) vertical 300 meters
>>>>(99.99% prob.) horizontal 340 nanoseconds time (95% prob.)
>>>
>>>"What is the status of Selective Availability (SA)?
>>
>> What does SA have to do with the 2008 accuracy specification I posted?
>
> IIRC, SA encrypted the low order bits in order to prevent GPS being used
> for weapons targeting and other anti-social behavior.

That's true, but Clinton shut it off in 2001 and it hasn't been a problem
for nearly seven years now.

--
$109,000,000 in income! Capitalism works GREAT for Billary...
...why does she want Marxism for us?