What is a 'GPS enabled' phone.

Discussion in 'Global Navigation Satellite Systems' started by James A. Donald, Dec 20, 2003.

  1. Pardon my paranoia, but does "GPS enabled" mean that my cell phone can
    tell me where where I am, and tell other people where I am when I
    choose to use their services, or does it mean the phone company can
    track my movements as if I was a registered sex offender wearing a
    locator ankle bracelet?
     
    James A. Donald, Dec 20, 2003
    #1
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  2. James A. Donald

    Tony Clark Guest

    Which phone are you talking about specifically? I would think that GPS
    enabled means it can recieve a GPS signal for the purpose of displaying your
    location. There are phones systems already that have something called Friend
    Finder (or something like that) that will allow your friends (or co-workers)
    to get an approximate location on you, IF you enable that feature. This is
    not GPS but uses some sort of triangulation based on cell towers you are
    using.

    TC

    PS - Big Brother already knows where you are and where you've been....LOL


    "James A. Donald" <> wrote in message
    news:...
    > Pardon my paranoia, but does "GPS enabled" mean that my cell phone can
    > tell me where where I am, and tell other people where I am when I
    > choose to use their services, or does it mean the phone company can
    > track my movements as if I was a registered sex offender wearing a
    > locator ankle bracelet?
     
    Tony Clark, Dec 20, 2003
    #2
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  3. James A. Donald

    noVote Guest

    I thought GPS enabled phones were for emergency 911 locating. Things like
    car jacking and kidnapping. This would make it easy for the police to find
    you in the event of an emergency.

    Richard

    "Tony Clark" <> wrote in message
    news:uN1Fb.12673$...
    > Which phone are you talking about specifically? I would think that GPS
    > enabled means it can recieve a GPS signal for the purpose of displaying

    your
    > location. There are phones systems already that have something called

    Friend
    > Finder (or something like that) that will allow your friends (or

    co-workers)
    > to get an approximate location on you, IF you enable that feature. This is
    > not GPS but uses some sort of triangulation based on cell towers you are
    > using.
    >
    > TC
    >
    > PS - Big Brother already knows where you are and where you've been....LOL
    >
    >
    > "James A. Donald" <> wrote in message
    > news:...
    > > Pardon my paranoia, but does "GPS enabled" mean that my cell phone can
    > > tell me where where I am, and tell other people where I am when I
    > > choose to use their services, or does it mean the phone company can
    > > track my movements as if I was a registered sex offender wearing a
    > > locator ankle bracelet?

    >
    >
     
    noVote, Dec 20, 2003
    #3
  4. James A. Donald

    Richard Ness Guest

    DING!!! Correct answer.

    A GPS enabled phone is not a GPS device. It won't give you your position.
    It WILL give your position to an E911 operator, or for enhanced services.

    It does have the capability, with the systems assistance, of pin pointing your location.
    The key is "with the systems assistance". The phone only has a part of the capability
    to read the satellites and compute your position. The system actually does the bulk of
    the work, thus, the phone is not a stand alone GPS device, just one part of it.



    "noVote" <> wrote in message news:732Fb.125292$%...
    > I thought GPS enabled phones were for emergency 911 locating. Things like
    > car jacking and kidnapping. This would make it easy for the police to find
    > you in the event of an emergency.
    >
    > Richard
    >
    > "Tony Clark" <> wrote in message
    > news:uN1Fb.12673$...
    > > Which phone are you talking about specifically? I would think that GPS
    > > enabled means it can recieve a GPS signal for the purpose of displaying

    > your
    > > location. There are phones systems already that have something called

    > Friend
    > > Finder (or something like that) that will allow your friends (or

    > co-workers)
    > > to get an approximate location on you, IF you enable that feature. This is
    > > not GPS but uses some sort of triangulation based on cell towers you are
    > > using.
    > >
    > > TC
    > >
    > > PS - Big Brother already knows where you are and where you've been....LOL
    > >
    > >
    > > "James A. Donald" <> wrote in message
    > > news:...
    > > > Pardon my paranoia, but does "GPS enabled" mean that my cell phone can
    > > > tell me where where I am, and tell other people where I am when I
    > > > choose to use their services, or does it mean the phone company can
    > > > track my movements as if I was a registered sex offender wearing a
    > > > locator ankle bracelet?

    > >
    > >

    >
    >
     
    Richard Ness, Dec 20, 2003
    #4
  5. James A. Donald

    Bob Kegel Guest

    "James A. Donald" <> wrote in message
    news:...

    > Pardon my paranoia, but does "GPS enabled" mean that my cell phone can
    > tell me where where I am, and tell other people where I am when I
    > choose to use their services,


    Potentially. These services have yet to be implemented outside a few test
    markets.

    > or does it mean the phone company can
    > track my movements as if I was a registered sex offender wearing a
    > locator ankle bracelet?


    The phone company has ALWAYS known where your cell phone is, so long as it
    was turned on. A cell phone is a radio transmitter. Anyone with the right
    equipment can track it.
     
    Bob Kegel, Dec 20, 2003
    #5
  6. "Richard Ness" <> wrote in message
    news:...
    > DING!!! Correct answer.
    >
    > A GPS enabled phone is not a GPS device. It won't give you your position.
    > It WILL give your position to an E911 operator, or for enhanced services.
    >
    > It does have the capability, with the systems assistance, of pin pointing

    your location.
    > The key is "with the systems assistance". The phone only has a part of the

    capability
    > to read the satellites and compute your position. The system actually does

    the bulk of
    > the work, thus, the phone is not a stand alone GPS device, just one part

    of it.
    >


    A GPS phone can be a GPS device. I carry a Motorola i88s that I can go into
    the menu and it will show me my Long. and Lat., how many satellites were
    used to obtain that position, and the estimated accuracy of that reading.
    Also, it has the ability to output NMEA sentences to the accessory port. It
    will, and has, obtained GPS positioning when I am out of Nextel coverage
    area, caching the location points until I am back in coverage.

    My company subscribes to a service that captures that data and keeps it for
    purposes of dispatching the closest person to a service call, delivery,
    whatever. (www.cell-tell.com). Nextel is my cell phone service provider,
    and as far as I know they are the only ones that have implemented the GPS
    technology in an open architecture fashion so that other applications can
    get a read for the GPS receiver.

    That being said, I have control of the application, whether it is running or
    not. The phone also has a security feature built into it that does not
    allow my position to be obtained from the GPS.

    As stated by another poster, the cell phone company pretty much knows your
    position all the time anyway based on what cell towers you are talking to,
    and maybe GPS information as well.
     
    Phillip T. Murphy, Dec 20, 2003
    #6
  7. "James A. Donald" <> wrote in message news:...
    > Pardon my paranoia, but does "GPS enabled" mean that my cell phone can
    > tell me where where I am, and tell other people where I am when I
    > choose to use their services, or does it mean the phone company can
    > track my movements as if I was a registered sex offender wearing a
    > locator ankle bracelet?


    Yes.
    It means you no longer need wear an ankle bracelet.
    A gold neck chain or a gaudy oversized ring will suffice.
    ---JRC---
     
    John R. Copeland, Dec 20, 2003
    #7
  8. James A. Donald

    The Steven Guest

    > Pardon my paranoia, but does "GPS enabled" mean that my cell phone can
    > tell me where where I am, and tell other people where I am when I
    > choose to use their services, or does it mean the phone company can
    > track my movements as if I was a registered sex offender wearing a
    > locator ankle bracelet?


    Yes, some new(er) phones have GPS. Some possible services include location
    based advertising, talking navigation aid, E-911, etc... And yes, Big
    Brother "could" be watching you... but you "know they wouldn't ever do
    that..."

    --

    S.

    -My other computer is a Cray 1.



    ---
    Outgoing mail is certified Virus Free.
    Checked by AVG anti-virus system (http://www.grisoft.com).
    Version: 6.0.552 / Virus Database: 344 - Release Date: 12/16/2003
     
    The Steven, Dec 21, 2003
    #8
  9. James A. Donald

    The Steven Guest

    > The phone company has ALWAYS known where your cell phone is, so long as it
    > was turned on. A cell phone is a radio transmitter. Anyone with the right
    > equipment can track it.


    Within a range of 200~300 meters.... But with phones like the i88 its more
    like standard GPS

    --

    S.

    -My other computer is a Cray 1.


    ---
    Outgoing mail is certified Virus Free.
    Checked by AVG anti-virus system (http://www.grisoft.com).
    Version: 6.0.552 / Virus Database: 344 - Release Date: 12/16/2003
     
    The Steven, Dec 21, 2003
    #9
  10. James A. Donald

    Tom J Guest

    The Steven wrote:
    >>Pardon my paranoia, but does "GPS enabled" mean that my cell phone can
    >>tell me where where I am, and tell other people where I am when I
    >>choose to use their services, or does it mean the phone company can
    >>track my movements as if I was a registered sex offender wearing a
    >>locator ankle bracelet?

    >
    >
    > Yes, some new(er) phones have GPS. Some possible services include location
    > based advertising, talking navigation aid, E-911, etc... And yes, Big
    > Brother "could" be watching you... but you "know they wouldn't ever do
    > that..."
    >


    In the Atlanta area about a month ago, 2 women were murdered. Someone
    saw the killer running from the house talking on a cell phone and jump
    in a truck. With the description of the truck, the police determined
    who the killer was, went to his home and obtained his cell phone number
    and had a tracer put on it. Within minutes the phone was detected in
    one of the northern states, Minnesota I think, and within another few
    minutes the police had him cornered in a hospital parking lot. He still
    had the murder weapon with him also, but was in an auto, so yes, you can
    be traced with the cell phone.

    Tom J
     
    Tom J, Dec 21, 2003
    #10
  11. On 20 Dec 2003 11:47:31 -0800, (James A. Donald)
    wrote:

    |Pardon my paranoia, but does "GPS enabled" mean that my cell phone can
    |tell me where where I am, and tell other people where I am when I
    |choose to use their services, or does it mean the phone company can
    |track my movements as if I was a registered sex offender wearing a
    |locator ankle bracelet?

    December 21, 2003
    Lost? Hiding? Your Cellphone Is Keeping Tabs
    By AMY HARMON

    n the train returning to Armonk, N.Y., from a recent shopping trip in
    Manhattan with her friends, Britney Lutz, 15, had the odd sensation
    that her father was watching her.

    He very well could have been. Ms. Lutz's father, Kerry, recently
    equipped his daughters with cellular phones that let him see where
    they are on a computer map at any given moment. Earlier that day, he
    had tracked Britney as she arrived in Grand Central Terminal. Later,
    calling up the map on his own cellphone screen, he noticed she was in
    SoHo.

    Mr. Lutz did not happen to be checking when Britney developed pangs of
    guilt for taking a train home later than she was supposed to, but the
    system worked just as he had hoped: she volunteered the information
    that evening.

    "Before, they might not have told me the truth, but now I know they're
    going to," said Mr. Lutz, 46, a lawyer who has been particularly
    protective of Britney and her sister, Chelsea, 17, since his wife died
    several years ago. "They know I care. And they know I'm watching."

    Driven by worries about safety, the need for accountability, and
    perhaps a certain "I Spy" impulse, families and employers are adopting
    surveillance technology once used mostly to track soldiers and
    prisoners. New electronic services with names like uLocate and Wherify
    Wireless make a very personal piece of information for cellphone users
    — physical location — harder to mask.

    But privacy advocates say the lack of legal clarity about who can gain
    access to location information poses a serious risk. And some users
    say the technology threatens an everyday autonomy that is largely
    taken for granted. The devices, they say, promote the scrutiny of
    small decisions — where to have lunch, when to take a break, how fast
    to drive — rather than general accountability.

    "It's like a weird thought I get sometimes, like `he definitely knows
    where I am right now, and he's looking to see if I'm somewhere he
    might not approve of,' " said Britney Lutz. "I wonder what it will be
    like when I start to drive."

    Still, personal location devices are beginning to catch on, largely
    because cellular phones are increasingly coming with a built-in
    tether. A federal mandate that wireless carriers be able to locate
    callers who dial 911 automatically by late 2005 means that millions of
    phones already keep track of their owners' whereabouts. Analysts
    predict that as many as 42 million Americans will be using some form
    of "location-aware" technology in 2005.

    Wireless companies and start-up firms are weaving the satellite system
    known as G.P.S., or Global Positioning System, which was begun by the
    United States military in the 1970's, into the cellular phone network
    and the Internet to sell products and services that provide location
    information.

    After fixing an individual's location relative to a network of G.P.S.
    satellites orbiting 12,000 miles above the earth — or, more crudely,
    by the time it takes signals to bounce off nearby cell towers —
    personal locator services transmit the constantly updated information
    to a central database, where customers can retrieve it through the
    Internet, telephone or pager.

    Until recently, one of the main civilian uses of G.P.S. was in devices
    issued by the criminal justice system to track offenders as a
    condition of their parole or probation. The new generation of tracking
    devices has moved well beyond that population and now takes many
    forms, from plastic bracelets that can be locked onto children to
    small boxes with tiny antennae that can be placed unobtrusively in
    cars.

    "We are moving into a world where your location is going to be known
    at all times by some electronic device," said Larry Smarr, director of
    the California Institute for Telecommunications and Information
    Technology. "It's inevitable. So we should be talking about its
    consequences before it's too late."

    Some of those consequences have not been spelled out. Will federal
    investigators be allowed to retrieve information on your recent
    whereabouts from a private service like uLocate, or your cellular
    carrier? Can the local Starbucks store send advertisements to your
    phone when it knows you are nearby, without your explicit permission?

    Because the new electronic surveillance services are still in their
    infancy, there are few answers, but the debate over the boundaries of
    privacy in a more transparent world is already taking shape. Teenagers
    in particular tend to be skeptical of the new technology's value.

    "Cellphones would lose their appeal if they became tracking devices,"
    said Nate Bingham, 16, of Seattle. "I think if your parents really
    care that much they should just put a leash on you."

    Mr. Bingham's parents use an AT&T service called Find Friend that lets
    them see his general location when his cellphone is on, based on the
    company's nearest cellular tower. He said his mother had at times
    asked him where he was and then used the service to see if he was
    telling the truth. He admits to turning the phone off occasionally
    when he doesn't want to be found.

    That won't work in the Pratt household, in Garden City, N.Y., where
    Jason, 13, and Ashley, 11, were given new Nextel cellphones on the
    condition that they be kept on at all times. With uLocate, Tom Pratt
    set up his account on the company's Web site to establish a "geofence"
    around his home and his children's school. Every time the kids leave a
    400-foot radius of either place, he gets an automatic e-mail alert:
    "Ashley has exited Home at 08:18 AM," read a typical message last
    week.

    Jason Pratt said there were advantages to being watched. He no longer
    has to call his mother to let her know where he is. Instead, she can
    press a "locate" button on her phone and see for herself. So long as
    Jason's phone is running the uLocate software, it transmits his
    location information every two minutes. Jason's 17-year-old brother,
    Matthew, however, kept his older cellphone — even though it had poor
    reception — rather than submit to the new deal.

    Howard Boyle, president of a fire sprinkler installation company in
    Woodside, N.Y., presented his employees with no such choice. The five
    workers who have been given company phones with the G.P.S. feature
    have not been told that Mr. Boyle can find out if they have arrived at
    a work site, and whether they are walking around in it or sitting
    still.

    "They don't need to know," said Mr. Boyle, who hopes the service will
    help him determine the truth when clients claim they are being
    overbilled for the time his employees spent at their location. "I can
    call them and say, `Where are you now?' while I'm looking at the
    screen and knowing exactly where they are, just to make sure they're
    not telling me they're somewhere else."

    But it is not just the unnerving effect of uncovering small lies that
    has some users of the technology worried. Like caller I.D., location
    devices lift the curtain on a zone of privacy that many Americans
    value, even if they rarely have anything serious to hide.

    "Think back to when you were a teenager and your mom or dad said, `I
    don't want you to do this,' and you said, `yeah, yeah, yeah,' because
    you knew you could do it and they wouldn't know," said Graham Clarke,
    president of National Scientific, which makes several G.P.S. tracking
    devices. "Those days are gone now, because they actually can know."

    Mr. Clarke recently installed a tracking device called Followit in the
    Jeep Wrangler of his 17-year-old son, Gordon. It alerts him if Gordon
    has exceeded 60 m.p.h. or traveled beyond preset boundaries.

    Advocates of location-aware technology insist that its safety benefits
    — like locating a 911 caller or a stolen car — outweigh the privacy
    issues.

    And for Donna Phillips, 66, whose husband, Hubie, has Alzheimer's
    disease, the ability to lock a G.P.S.-enabled bracelet from Wherify
    Wireless around Mr. Phillips's fanny pack when he goes out has meant
    an end to panicked searches when he fails to come home. Now her
    granddaughter can help her find her husband on the Wherify Wireless
    Web site, which displays the location information transmitted from the
    bracelet when an authorized user logs on.

    About two weeks ago, Mr. Phillips, 90, boarded a bus near his home in
    Rancho Park, Calif., and traveled several miles before switching to
    another bus. Because he was moving too fast for his wife to catch up,
    she called the police, who were able to pinpoint his location through
    the Wherify Wireless service to pick him up.

    Critics of the new technology do not dispute its usefulness, but worry
    that it will become ubiquitous before legal guidelines are
    established.

    Last year, the Federal Communications Commission turned down a request
    from the cellular phone industry's association and privacy groups for
    guidance on such matters. For the moment, the questions of trust and
    tracking are being raised largely in the sphere of family and personal
    relationships, rather than in the public arenas of government and
    business.

    Jerold Surdahl, 40, an administrator in a building management office
    in Centerville, Ohio, said he started using the uLocate service to
    communicate with colleagues. Now, he is intrigued by the possibility
    of stashing a location-tracking phone in the trunk of his wife's car.

    "I'm not expecting or hoping or wanting to find something, but I would
    just like to explore the possibilities," Mr. Surdahl said. "I'd tell
    her about it later."


    http://www.nytimes.com/2003/12/21/technology/21WATC.html
     
    R. David Steele, Dec 21, 2003
    #11
  12. James A. Donald

    Graham Guest

    > > The phone company has ALWAYS known where your cell phone is, so long as it
    > > was turned on. A cell phone is a radio transmitter. Anyone with the right
    > > equipment can track it.



    The Steven wrote:
    > Within a range of 200~300 meters.... But with phones like the i88 its more
    > like standard GPS


    Remember when standard GPS was a range of 200~300 meters...
     
    Graham, Dec 21, 2003
    #12
  13. James A. Donald

    Graham Guest

    Tom J wrote:
    > In the Atlanta area about a month ago, 2 women were murdered. Someone
    > saw the killer running from the house talking on a cell phone and jump
    > in a truck. With the description of the truck, the police determined
    > who the killer was, went to his home and obtained his cell phone number
    > and had a tracer put on it. Within minutes the phone was detected in
    > one of the northern states, Minnesota I think, and within another few
    > minutes the police had him cornered in a hospital parking lot. He still
    > had the murder weapon with him also, but was in an auto, so yes, you can
    > be traced with the cell phone.



    Maybe I'm missing something here, but how did the killer get from
    Atlanta to Minnesota in minutes?
     
    Graham, Dec 21, 2003
    #13
  14. James A. Donald

    Tony Clark Guest

    I think the time from when the killer got into the truck and the time the
    police went to his house was more than a few minutes. :)

    TC


    "Graham" <> wrote in message
    news:...
    > Tom J wrote:
    > > In the Atlanta area about a month ago, 2 women were murdered. Someone
    > > saw the killer running from the house talking on a cell phone and jump
    > > in a truck. With the description of the truck, the police determined
    > > who the killer was, went to his home and obtained his cell phone number
    > > and had a tracer put on it. Within minutes the phone was detected in
    > > one of the northern states, Minnesota I think, and within another few
    > > minutes the police had him cornered in a hospital parking lot. He still
    > > had the murder weapon with him also, but was in an auto, so yes, you can
    > > be traced with the cell phone.

    >
    >
    > Maybe I'm missing something here, but how did the killer get from
    > Atlanta to Minnesota in minutes?
     
    Tony Clark, Dec 21, 2003
    #14
  15. James A. Donald

    The Steven Guest

    > Remember when standard GPS was a range of 200~300 meters...

    Yes I do, but that was because of a little thing called Selective
    Availability.

    Locating cellular phones was done another way.
    Here it is, and I will explain it in "english".

    First, if you are an engineer for a cellular company, please don't throw
    rocks at my house for not being precise. This is for the basic understanding
    of the general public.

    1.)Get a map of your local area, like a county or township level map, and a
    compass (the kind with a pencil on one end an a point on the other, not the
    kind that tells you where North is)

    2.) Drive around and find a cellular tower. Then find it on your map.

    3.)Draw a circle corresponding to 6 miles around it. Count the number of
    elements on the tower three, and nine are most common.

    4.)Divide the circle by the number of elements. (120 degrees for 3, 40
    degrees for nine)

    5.) Now using the tower on your map as the center, make six smaller circles
    on your map. It should now look something like a dart-board with the tower
    as the bulls-eye.

    Now, when the cellular phone and the tower site communicate with each other
    on one of the control channels, the tower can tell the phone to adjust it's
    power output up or down to one of seven power levels.

    The cellular system can and does monitor (for internal quality control and
    billing) what cell site the phone is nearest, what antenna element is
    communicating with the phone, and what power level the phone was told to set
    it self to.

    So, look at the map and picture of a dart board you made. Look at any block
    on that grid, that is an example of the margin of error you could expect
    from a non GPS cellular phone.


    --

    S.

    -My other computer is a Cray 1.


    ---
    Outgoing mail is certified Virus Free.
    Checked by AVG anti-virus system (http://www.grisoft.com).
    Version: 6.0.553 / Virus Database: 345 - Release Date: 12/18/2003
     
    The Steven, Dec 21, 2003
    #15
  16. James A. Donald

    Dave L Guest

    Saw a demonstration of a gps enabled phone the other day. Telus in Canada.
    When the feature is enabled, it reports the position of the phone 1X a
    minute. Someone with authorization who clicks on the trail on the map has
    its location, and the speed at that moment is displayed as well.
     
    Dave L, Dec 21, 2003
    #16
  17. James A. Donald

    sec Guest

    On Sat, 20 Dec 2003 12:41:08 -0800, "Bob Kegel" <seventy 2002 at hotmail
    dot com> wrote:

    >"James A. Donald" <> wrote in message
    >news:...
    >
    >> Pardon my paranoia, but does "GPS enabled" mean that my cell phone can
    >> tell me where where I am, and tell other people where I am when I
    >> choose to use their services,

    >
    >Potentially. These services have yet to be implemented outside a few test
    >markets.
    >
    >> or does it mean the phone company can
    >> track my movements as if I was a registered sex offender wearing a
    >> locator ankle bracelet?

    >
    >The phone company has ALWAYS known where your cell phone is, so long as it
    >was turned on. A cell phone is a radio transmitter. Anyone with the right
    >equipment can track it.


    False. The phone company can query how strong of a signal its towers
    are receiving from your phone; that's it. The cellular transceivers
    need this info so that they can tell your phone when to handoff (proper
    term) to another site.

    Now could two or more towers use this to triangulate your exact
    position? No. They can determine what general area you are in, but
    nothing more. They might even speculate that your driving a particular
    stretch of road based on what sites you're handing off to, but locate
    you in an emergency? Poppycock!

    Let's say a particular cell site is receiving 1mW from your phone. The
    site doesn't know if that's coming from a 0.6Watt phone 1km away, or a
    3Watt phone 20km away. Most cell sites handle a radius of 30km. Do the
    math; you could be anywhere in a very large area.

    All modern cell phones (built after Oct 2001) are required, by the FCC,
    to have GPSr technology in them and can therefore be tracked. But this
    has, as you suggested, not ALWAYS been the case.

    For more detail, read:

    http://electronics.howstuffworks.com/cell-phone.htm
    http://people.howstuffworks.com/location-tracking.htm
     
    sec, Dec 22, 2003
    #17
  18. sec <> wrote in message news:<>...
    > On Sat, 20 Dec 2003 12:41:08 -0800, "Bob Kegel" <seventy 2002 at hotmail
    > dot com> wrote:
    >
    > >"James A. Donald" <> wrote in message
    > >news:...
    > >
    > >> Pardon my paranoia, but does "GPS enabled" mean that my cell phone can
    > >> tell me where where I am, and tell other people where I am when I
    > >> choose to use their services,

    > >
    > >Potentially. These services have yet to be implemented outside a few test
    > >markets.
    > >
    > >> or does it mean the phone company can
    > >> track my movements as if I was a registered sex offender wearing a
    > >> locator ankle bracelet?

    > >
    > >The phone company has ALWAYS known where your cell phone is, so long as it
    > >was turned on. A cell phone is a radio transmitter. Anyone with the right
    > >equipment can track it.

    >
    > False. The phone company can query how strong of a signal its towers
    > are receiving from your phone; that's it. The cellular transceivers
    > need this info so that they can tell your phone when to handoff (proper
    > term) to another site.
    >
    > Now could two or more towers use this to triangulate your exact
    > position? No. They can determine what general area you are in, but
    > nothing more. They might even speculate that your driving a particular
    > stretch of road based on what sites you're handing off to, but locate
    > you in an emergency? Poppycock!
    >
    > Let's say a particular cell site is receiving 1mW from your phone. The
    > site doesn't know if that's coming from a 0.6Watt phone 1km away, or a
    > 3Watt phone 20km away. Most cell sites handle a radius of 30km. Do the
    > math; you could be anywhere in a very large area.
    >
    > All modern cell phones (built after Oct 2001) are required, by the FCC,
    > to have GPSr technology in them and can therefore be tracked. But this
    > has, as you suggested, not ALWAYS been the case.


    They are not required to have a GPS in them but they are required to
    be able to report their position. This can be done with a GPS or can
    be accomplished by other means such as triangulating off of several
    towers. As you state this triangulation capability is not built into
    current cell-phone infrastructure and would require modifications of
    the cell towers to do triangulation so most systems have opted for the
    augmented GPS approach.

    Dale

    >
    > For more detail, read:
    >
    > http://electronics.howstuffworks.com/cell-phone.htm
    > http://people.howstuffworks.com/location-tracking.htm
     
    Dale DePriest, Dec 22, 2003
    #18
  19. James A. Donald

    matt weber Guest

    On Mon, 22 Dec 2003 00:41:28 GMT, sec <> wrote:

    >On Sat, 20 Dec 2003 12:41:08 -0800, "Bob Kegel" <seventy 2002 at hotmail
    >dot com> wrote:
    >
    >>"James A. Donald" <> wrote in message
    >>news:...
    >>
    >>> Pardon my paranoia, but does "GPS enabled" mean that my cell phone can
    >>> tell me where where I am, and tell other people where I am when I
    >>> choose to use their services,

    >>
    >>Potentially. These services have yet to be implemented outside a few test
    >>markets.
    >>
    >>> or does it mean the phone company can
    >>> track my movements as if I was a registered sex offender wearing a
    >>> locator ankle bracelet?

    >>
    >>The phone company has ALWAYS known where your cell phone is, so long as it
    >>was turned on. A cell phone is a radio transmitter. Anyone with the right
    >>equipment can track it.

    >
    >False. The phone company can query how strong of a signal its towers
    >are receiving from your phone; that's it. The cellular transceivers
    >need this info so that they can tell your phone when to handoff (proper
    >term) to another site.
    >
    >Now could two or more towers use this to triangulate your exact
    >position? No. They can determine what general area you are in, but
    >nothing more. They might even speculate that your driving a particular
    >stretch of road based on what sites you're handing off to, but locate
    >you in an emergency? Poppycock!

    WRONG. Both CDMA and GSM are very timing sensitive. For example a
    single GSM tower without any triangulation can usually provide a
    bearing that is accurate to +/- 30 degrees, and and distance that is
    +/- about 1/4 mile (that comes from timing advance in GSM), and that
    doesn't involve doing anything fancy at all. If you are prepared to
    look more closely at the timing beyond timing advance, i.e. where it
    falls within the timing slot, you can get the distance down to about
    +/- 50 feet without much difficult.

    With two towers, you don't trangulate based on bearing, you do it
    based upon timing. If you know the radius from the two towers +/-
    about 50 feet, the intersection of those two circles is usually going
    to be a circle about 50 feet in radius.

    The position calculation used by all services is based upon signal
    timings.

    However they have to be looking for you to have two towers listening.
    Most of the time, a fair amount of trouble is expended getting
    anything other then the first tower to completely ignore you...
    >
    >Let's say a particular cell site is receiving 1mW from your phone. The
    >site doesn't know if that's coming from a 0.6Watt phone 1km away, or a
    >3Watt phone 20km away. Most cell sites handle a radius of 30km. Do the
    >math; you could be anywhere in a very large area.


    GSM systems, particularly within cities have much much smaller radii.
    otherwise you run out system capacity very quickly, and if you are
    getting 1 milliwatt at the BTS, you can bet the BTS has commanded the
    cell phone transmitter output downward. The timing on a GSM network is
    such that you actually have to know the distance to the phone +/-
    about 1/2 km just to keep the signal inside the assigned time slot.
    >
    >All modern cell phones (built after Oct 2001) are required, by the FCC,
    >to have GPSr technology in them and can therefore be tracked. But this
    >has, as you suggested, not ALWAYS been the case.
    >
    >For more detail, read:
    >
    > http://electronics.howstuffworks.com/cell-phone.htm
    > http://people.howstuffworks.com/location-tracking.htm
     
    matt weber, Dec 23, 2003
    #19
  20. James A. Donald

    Allen Smith Guest

    There are only three phones have an actual GPS chip set in them that
    the end user can access. All are for the Nextel network and are made
    by Motorola. The i58/i88 are B&W screen, non-flip phones and The i730
    is a color flip phone. If you buy a serial cable you can send NMEA
    sentances to a laptop, even if you are out of Nextel coverage. There
    is also a service that makes uses of the data:
    http://www.uLocate.com to track phones from other phones or on a web
    site

    Allen Smith
    track your cell phone in real-time
    http://www.gadgeteer.org
     
    Allen Smith, Dec 23, 2003
    #20
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