will the SDK provide access to E911-based location?

Discussion in 'iPhone' started by ///alpinepower, Oct 17, 2007.

  1. kdarling macrumors demi-god

    kdarling

    Joined:
    Jun 9, 2007
    Location:
    Cabin by a lake
    #2
    No, it doesn't work that way.

    E911 services take two forms:

    1) GPS on the phone. The phone knows its own position.

    2) Tower-based radio-location. Only the towers know the phone's position.

    ATT chose method #2. That means the iPhone does NOT know its own location.

    You could buy the information from the carrier and have the phone ask a web service for it, though.
     
  2. ///alpinepower thread starter macrumors member

    Joined:
    Aug 13, 2007
    #3
    I think all carriers use #2. But, it's just a few lines of code or a switch that would allow an application on the handset to use that information.
     
  3. kdarling macrumors demi-god

    kdarling

    Joined:
    Jun 9, 2007
    Location:
    Cabin by a lake
    #4
    Again, no :)

    Verizon, Sprint, Nextel chose onboard GPS, which meant slightly more costly handsets. Often it's assisted-GPS (A-GPS), which means the phone asks the towers for help in calculations, accuracy, base position, etc. In any case, the phone knows where it is and so does the tower (if it's asked by E911).

    ATT and the others chose tower-only-based. The phone doesn't have any idea where it is, or that it's even being located. The only way for the phone to know its position, is to make an internet request through a provider, who asks the carrier to locate you. This costs money, requires sign-up, requires permission. Not gonna happen unless Apple creates such a paid service.

    Kevin
    Senior Engineer
     
  4. Merlyn3D macrumors regular

    Joined:
    May 15, 2006
    #5
    I would venture to say if they didn't put it in google maps, then no.
     
  5. ///alpinepower thread starter macrumors member

    Joined:
    Aug 13, 2007
    #6

    looks like this has a preliminary answer already:

    http://google.com/gmm/mylocation.html

    Kevin - thanks for the irrelevant submission of your title?
     
  6. kdarling macrumors demi-god

    kdarling

    Joined:
    Jun 9, 2007
    Location:
    Cabin by a lake
    #7
    Thanks. But your original questions were about E911 location, not hit and miss self-triangulation.

    I find it can save people's time if they know an engineer is replying, not just someone who stayed at a Holiday Inn Express last night ;-)
     
  7. snook911 macrumors 6502a

    Joined:
    Aug 13, 2007
    Location:
    Yorba Linda, CA
    #8
    The question is how do we know you are a real engineer?


    Joe
    Nasa Engineer
     
  8. kdarling macrumors demi-god

    kdarling

    Joined:
    Jun 9, 2007
    Location:
    Cabin by a lake
    #9
    Easy... the pocket protector and slide rule give me away :D
     

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