if you use your mifi or phone as a hotspot

Discussion in 'iPad' started by flyguy206, Mar 20, 2010.

  1. flyguy206 macrumors 6502a

    Aug 5, 2008
    would you not have just as good loctaion finding on ipad as gps?
  2. lionheartednyhc macrumors 65816


    Jul 13, 2009
    No. Ipad with 3g has has assisted GPS. Wifi only does not.
  3. gwynne macrumors 68000


    Mar 11, 2010
    This statement is based more on intuition that actual data, but I think a device that talks to one satellite continuously is going to be more reliable than something that has to switch from one cell tower to another as you move.

    I'm totally open to being told this theory is wrong, though. <3 my Garmin.
  4. lionheartednyhc macrumors 65816


    Jul 13, 2009
    Your right. The wifi version, like the ipod touch, is going to be inaccurate because it does not use satellite data.
  5. diabolic macrumors 68000

    Jun 13, 2007
    Austin, Texas
    The wifi iPad wouldn't have access to any of the location data on the phone. It would think it's connected to a wifi network, because that is all it sees.

    Depending where you are, wifi location services aren't necessarily very accurate. Where I live, it's not accurate at all.
  6. kdarling macrumors P6


    Jun 9, 2007
    First university coding class = 47 years ago
    The answer is No.

    1) GPS is more accurate and works away from hotspots. The only exception would be is if you're sitting right next to a perfectly mapped hotspot, which would be a rare thing.

    2) A phone or MiFi hotspot can't be used for locating, since it's usually constantly moving and would not be mapped to one location by Skyhook.
  7. Gav2k macrumors G3


    Jul 24, 2009

    Gps devices do not talk to satellites in any way.
  8. xraydoc macrumors 604


    Oct 9, 2005
    But the satellites "talk" to the GPS device.

    The answer to the OP's question is:

    No. The wifi-only iPad has no GPS chip, so it cannot receive geolocation information from the GPS satellites.

    A company called SkyHook as gone around the country and mapped the location of many fixed WiFi hotspots. So, if your iPad is connected to a hotspot at, say, Starbucks, then the Google Maps app will identify your location.

    But, if someone were to pick up and move that Starbuck's equipment to a new location, then the Google Maps app will mislocate you (or at least until SkyHook, Inc. remaps that hotspots location).

    Devices like the MiFi don't pass the cell tower information to the connected device (or at least I've not found a way to do it with my Verizon MiFi).

    The 3G-enabled iPads include a GPS chip just like the iPhone does, and can use GPS, cell-tower triangulation and SkyHook for geolocation.
  9. avaloncourt macrumors 65816

    Oct 18, 2007
    You are correct, the location data would not pass. That's not the function of an access point so it wouldn't be possible. The only way to make it possible is to have an application running on the phone device that sends NMEA data but then you'd need to have an NMEA data aware application that knew to look for inbound location data and utilize it. That would require rewriting on both ends and the navigation and location-aware developers aren't going to develop for something that doesn't have guaranteed availability like an internal GPS chip itself. I don't know if the iPhone development environment even supports inbound NMEA data that has nothing to do with an internal GPS chip at all.

    At to the OP's post, that would be a bit like saying a blender should make toast since it's plugged into the same electrical circuit as the toaster. The mifi has its defined function and the ipad has it's own. You can't make the iPad wi-fi connection GPS-aware when the architecture between the two doesn't exist.
  10. SuperRob macrumors 6502

    Mar 14, 2011
    OK, except that apparently this isn't true. The iPhone does appear to pass some kind of location data to the iPad when tethered. I would guess that the GPS lock the phone gets gives it specific coordinates, which then get passed to the iPad as the location of the WiFi spot it's talking to.

  11. kdarling macrumors P6


    Jun 9, 2007
    First university coding class = 47 years ago
    Thanks. Very interesting. The question is, how is the tethering iPhone's location transmitted to the iPad. Some out of band comms, perhaps? A special port number?

    Since it only updates once a minute, it makes me wonder if it's done this way:

    (First off, I mentioned Skyhook's hotspot servers, but Apple dropped Skyhook and now uses their own WiFi location database.)

    The iPhone, knowing it's in tethering mode, could constantly (once a minute those tests seem to say) send its location up to Apple's location servers.

    So when the iPad sends its usual location request to Apple's servers , they could simply respond with the current GPS location of the iPhone associated with the hotspot's MAC address.

    We need to do some WiFi packet sniffing :)

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