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Discussion in 'iPhone' started by thisisarcadia, Dec 27, 2008.

  1. thisisarcadia macrumors 6502

    Joined:
    Jun 26, 2008
    Location:
    New Orleans, LA
    #1
    Ok so quick 2 questions! First is there a maximum number of character you can type on the iPhone when using SMS? Second question what is the difference from assisted GPS and real GPS?
     
  2. NotFound macrumors 6502a

    NotFound

    Joined:
    Nov 30, 2006
    #2
    No (I think) , the phone will split up your message into several messages depending on the amount of characters you type.
     
  3. mickbab macrumors 65816

    mickbab

    Joined:
    Sep 13, 2008
    Location:
    Sydney, Australia
    #3
    1. i believe it sends it as one message but you will be charged for more messages (i have a 160 character limit, so a 200 character text would cost the same as two)

    2. assisted GPS uses wifi and network towers to narrow down your location. 'real GPS' only relies on GPS satellites. so if you are indoors, or GPS can't locate you precisely, assisted GPS will show a circle of where it estimates you are, by triangulating between network towers and wifi points.

    any help?
     
  4. nickspohn macrumors 68040

    nickspohn

    Joined:
    Jun 9, 2007
    #4
    1) Simply put, no. But it might send in multiple texts. I've noticed this doesn't happen with AT&T users, but anyone else, every 160 letters is a text. There is no limit in the app though.

    2) aGPS is BETTER. Instead of having a satellite trying to locate you out of the sky, it has cellular towers put you in a general area, called cellular triangulation (they use this on phones when someone is missing for example). Then the GPS satellite pinpoints you.
     
  5. SFStateStudent macrumors 604

    SFStateStudent

    Joined:
    Aug 28, 2007
    Location:
    San Francisco California, USA
    #5
    +1 ^^^ I've seen some of my friends TM that have been long and broken up. And my take on A-GPS: Triangulates via cell towers with the cellphone's position; while Real GPS: Relies on actual GPS satellites determining your location (a little more accurate and faster?)...
     
  6. Eso macrumors 68000

    Eso

    Joined:
    Aug 14, 2008
    #6
    Eh, wrong. The original iPhone can do what you describe as A-GPS.

    aGPS is just GPS that first uses cell towers and wifi locations to estimate your position which allows the GPS satellites to find your location quicker.
     
  7. tsice19 macrumors 6502a

    tsice19

    Joined:
    Feb 16, 2008
    #7
    The first gen GPS just used cell towers to locate you.

    The 3G uses the cell towers to find you, and then the satellites to precisely locate you

    Right?
     
  8. SFStateStudent macrumors 604

    SFStateStudent

    Joined:
    Aug 28, 2007
    Location:
    San Francisco California, USA
    #8
    Eh, WRONG back at ya'

    Hopefully this will straighten a few things out; or maybe not:

    http://wmexperts.com/articles/gps_vs_agps_a_quick_tutorial.html
     
  9. ppc750fx macrumors 65816

    Joined:
    Aug 20, 2008
    #9
    Just a quick note: the iPhone doesn't use cellular triangulation.
     
  10. Eso macrumors 68000

    Eso

    Joined:
    Aug 14, 2008
    #10
  11. JML42691 macrumors 68020

    JML42691

    Joined:
    Oct 24, 2007
    #11
    Not to call anybody right or wrong, but the iPhone 3G uses a-GPS, which finds your position in this process:

    1.) It determines a general position (roughly 150-500 ft.) based on "loose" cellular and wifi triangulation.
    2.) The phone searches for the specific GPS satellites that you would be covered by in the general location determined in step 1, and it locates where you are precisely using GPS.

    This process is quicker than plain old GPS, as regular GPS has to determine where you are only by searching through all of the nearby satellites, and then determining what satellites will help yield the precise location, while the general location determined in step 1 tells the phone what satellites will give the precise location.

    The iPhone 3G uses a-GPS, while the first generation iPhone only use a hybrid of cellular and wifi triangulation, and the iPod touch only uses wifi triangulation (which can be inaccurate).

    a-GPS uses multiple sources to determine your location, giving a quicker result, but relying on the GPS satellites to give the exact location.
     

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