Internal "GPS"

Discussion in 'iOS Programming' started by cplav, Mar 18, 2009.

  1. cplav macrumors newbie

    Aug 27, 2008
    Is there a way through wifi or other to determine a person's location within a building? I put GPS in quotes because I am fairly certain that it only works externally but could be wrong.
  2. jnic macrumors 6502a

    Oct 24, 2008
    Depends how thick the roof is. You can often get a weak GPS signal in a two-story building.
  3. buckyballs macrumors regular

    Dec 22, 2006
    The only way you could theoretically do it is using GPS

    The issues with this is that GPS is only accurate to about 35 feet, which is fine when you're trying to find where you are on a street, but not accurate enough for a building (for example the room I'm in now is probably about 12 feet wide!)

    Second, the GPS signal usually isn't strong enough to penetrate reliably into buildings (in fact, since the signal slows through walls, even if you do get a signal, it may put you in the wrong place!)
  4. cplav thread starter macrumors newbie

    Aug 27, 2008
    Is there software that could pick up a signal from the phone to say where you were, essentially making the leap inside. It might not be on the map app but a third party map?

    I have a great idea I am working on and this is an area I'm trying to get through.
  5. johnnybluejeans macrumors 6502

    Jan 16, 2006
    New York, NY
    Pick up what signal? Picking up a signal implies hardware... software can't just pick up signals magically.
  6. cplav thread starter macrumors newbie

    Aug 27, 2008
    Correct, I understand there is no magic involved.

    What about bluetooth, can you create a signal using some kind of bluetooth device to create the possible locations and then write the software to pick up the signal if you are on a certain floor or room? Provided the hardware was in the right range?
  7. jpyc7 macrumors 6502

    Mar 8, 2009
    Denver, CO
    sounds possible

    You create a bluetooth device and put in each room/location. Each bluetooth device must be uniquely identified when it is placed in the room. The iPhone makes a bluetooth connection to the device and reads its identifier. The identifier could be the actual room info, or just a directory key that the iPhone has to look in to get human readable room info.

    The problem would seem to be having to create the uniquely identifiable bluetooth devices and then physically installing them around the building

    Printed signs are an example of unique identifiers that are deployed in buildings and use human eyes to decode. Some of them have braille so that human fingers can decode them.

    I don't know anything about the bluetooth protocol, so I don't know if they support broadcasting unique identifiers. I would think after the initial connection is made, you can query the device to get that information.

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