iPhone's GPS accuracy in the woods

Discussion in 'iPhone' started by moonman239, May 2, 2013.

  1. moonman239 macrumors 68000

    Joined:
    Mar 27, 2009
    #1
    I'm developing a Webapp that will estimate how wide a river is. What would happen is the user would load the app, then wait until the app decides its location fix is good enough. Currently, that means that the phone estimates that the user is no more than 55 feet away from his or her estimated location. My question is, how much accuracy can I really expect without having the user wait too long?
     
  2. Mrg02d macrumors 65816

    Joined:
    Jan 27, 2012
    #2
    Depends on the GPS chip,no? At work, our service guys have gps units that are accurate to under a foot.
     
  3. MuddyPaws1 macrumors 6502

    Joined:
    Jul 14, 2012
    #3
    Accurate to 55 feet isn't all that accurate at all.
     
  4. takeshi74 macrumors 601

    Joined:
    Feb 9, 2011
    #4
    http://www.gps.gov/systems/gps/performance/accuracy/

    55 feet is well above what you can expect from GPS.

    It's all relative. Consider the accuracy of tower triangulation which easily goes up to 2000m (depending on conditions) in my experience.
     
  5. ThatsMeRight macrumors 68020

    Joined:
    Sep 12, 2009
    #5
    GLONASS is also used (Russian variant of GPS), so accuracy should be much higher.
     
  6. old-wiz macrumors G3

    Joined:
    Mar 26, 2008
    Location:
    West Suburban Boston Ma
    #6
    Usually consumer grade GPS devices are accurate to no more than 3 meters, and then only in optimum conditions.
     
  7. moonman239 thread starter macrumors 68000

    Joined:
    Mar 27, 2009
    #7
    Is there anyone out there who has taken a 4s or a 5 away from civilization and used the GPS feature?
     
  8. avanpelt macrumors 68020

    Joined:
    Jun 2, 2010
    #8
    I haven't, but I assume you could simulate this by turning the cellular radio off. The GPS chip still functions with the cellular radio turned off on a newer iPhone, correct?
     
  9. moonman239 thread starter macrumors 68000

    Joined:
    Mar 27, 2009
    #9
    I've heard you can, but I have not personally verified that statement. I never actually used location services while away from a cell tower or WiFi hotspot.

    Edit: I just turned on airplane mode and attempted to get Maps to show me where I am, but the app told me to go to Settings and turn off airplane mode.
     

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