Can iPhone GPS work without data?

Discussion in 'iPhone' started by Faize, Nov 4, 2012.

  1. Faize macrumors member

    Joined:
    Sep 23, 2011
    #1
    If I was shipwrecked in the middle of the Atlantic Ocean and managed to get in contact with rescuers via a long-distance radio or something, would the iPhone's GPS receiver be able to at least provide my coordinates?

    Or does it simply not work when outside of the vincinity of a cell tower and not on a WiFi connection?
     
  2. ReValveiT macrumors regular

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    Sep 20, 2012
  3. Applejuiced macrumors Westmere

    Applejuiced

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    At the iPhone hacks section.
  4. Primejimbo macrumors 68040

    Joined:
    Aug 10, 2008
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    Around
    #4
    Couldn't you put it in airplane mode and try it, or does that shut off the GPS also?
     
  5. Small White Car macrumors G4

    Small White Car

    Joined:
    Aug 29, 2006
    Location:
    Washington DC
    #5
    The GPS info itself will work, but it really depends on the app you're using as to whether or not that will be helpful to you. It would have to have info stored within the app to tell you where you are.

    So some apps will display maps while offline and others won't if they get their maps from the internet each time.

    As the other poster said, test each app in airplane mode if you're curious to know which ones will help you when you're stranded and which ones won't.
     
  6. ffohwx macrumors member

    Joined:
    May 7, 2010
    Location:
    Fairfield, Ohio
    #6
    I use the TomTom GPS app in areas with no cell service all the time. If you are doing mapping, you need an app that has the maps built in.
     
  7. zorinlynx macrumors 601

    zorinlynx

    Joined:
    May 31, 2007
    Location:
    Florida, USA
    #7
    You can test GPS without cellular service. Just pop out your sim card. Notice GPS apps still work fine if they have local maps.

    The GPS radio is on the same chip as the cellular radio, but it's a separate function. It will function without cellular reception.
     
  8. mikechek1212 macrumors newbie

    Joined:
    Nov 5, 2012
    #8
    The iPhone GPS radio can definitely work without cell phone coverage. However, the Maps app does not work because it continuously loads the maps as your location changes. It does not save maps to the phone so when you lose data signal it can't refresh the maps and it doesn't work. However, the GPS radio will still be connected to satellites. I think this is a major flaw of the Maps app. To get around this, you can get one of the many apps that allows you to download and save maps to the phone so it can show your location on the pre-downloaded map. A GPS device (not a cell phone) like a Garmin or TomTom downloads all the map data directly to it and only uses GPS satellites to locate it.

    I don't know what uses you want GPS for but I use it for back country hiking in areas where there is no cell phone coverage. One problem with this is that your iPhone will constantly try to find a cell signal and this will drain your battery significantly. What I do is pre-download the maps to the area where I will be hiking and then I lock the SIM so it doesn't try to connect to cell towers. The GPS radio will not work when Airplane Mode is turned on. So that is why I lock the SIM. Removing it will do the same thing. Here is how to some info on locking the SIM: http://support.apple.com/kb/HT1316?viewlocale=en_US&locale=en_US I believe that the default PIN is 1111 but I'm not positive. If it doesn't work don't enter a PIN more than 2 times otherwise it will lock the pin and you will need get your Personal Unlocking Key (PUK) from your provider to unlock it.

    I don't know what apps are good for navigating streets but the app I use for hiking is Gaia GPS and I really like it.
     

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