iPhone 3G GPS not working in Japan

Discussion in 'iPhone' started by GatorNickk, Jun 30, 2009.

  1. GatorNickk macrumors newbie

    Jun 11, 2009
    I am currently in Okinawa, Japan on a business trip. When I got here, I took my sim card out of my iPhone so I didn't have to keep the phone in Airplane Mode the whole time. I did this mainly so I could turn on the GPS radio. GPS had no problem finding me in the airport in Tokyo, but ever since then it can't find me properly.

    I brought my Airport Express from home in Tampa to my hotel here and when I tell Google Maps to find me with Location Services on, it places me at my home in Tampa. However, when I am away from the hotel on a different wifi network, even outside, it always comes up saying "Your Location Cannot Be Determined".

    Does anyone know a fix for this? I realize that its "assisted" GPS, but thats really sad if it confused Okinawa, Japan for Tampa, FL because of a router. And why won't it find me out in about on other wifi networks. Makes now sense.
  2. avaloncourt macrumors 65816

    Oct 18, 2007
    I would say that since you can't determine any cell locations the only thing it has to fall back on is Skyhook registered access points. Looking at the Skyhook website they have very little information plotted for Japan.

    You already answered your own question regarding your Airport Express. It's been logged in the Skyhook database as being in Tampa. If you fire it up in London, Cairo, or Sydney it's always going to tell you that you're in Tampa if you're around it with the Airport Express turned on. It works off the MAC address of the router.

    Your GPS never found you in the airport, the Google link to Skyhook found you by a registered access point there. You would have to have been standing there for a very long time with a good view of the sky for it to ever have accumulated enough satellite data and then make a determination that you were in another part of the world. That would have taken at least 15-20 minutes.

    Here's how it found you in those couple of locations, even when it was wrong:


  3. GatorNickk thread starter macrumors newbie

    Jun 11, 2009
    Thats what I thought, but if this thing is supposed to be GPS, why does it have to rely on cell towers or wifi hotspots? Seems pretty weak to me. Wish Apple would have put a real GPS in here.

    Thanks for taking the time to reply though
  4. avaloncourt macrumors 65816

    Oct 18, 2007
    If you have wireless on it will first attempt to locate you through Skyhook. If it finds and access point in the database then it will tie you to that location quickly.

    If you were back where you started your trip you would acquire GPS pretty quickly. Because you were a huge difference from your last GPS fix it doesn't know where to find you and that takes a long time when you've changed continents. It's just the nature of GPS and GPS receivers. That's how it works. There's a lot of math involved.

    The cell towers and wi-fi access points get you there much more quickly.

    If you have no access to cell or wi-fi you'll eventually get a GPS location but you won't be able to download the maps and you'll just get a grey grid with no map.

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