Why no GPS in continuity

Discussion in 'iOS 8' started by kiranmk2, Nov 8, 2014.

  1. kiranmk2 macrumors 6502a

    kiranmk2

    Joined:
    Oct 4, 2008
    #1
    Just wondering why iOS didn't include support for GPS as part of continuity. It would have been great to share a iPhone's GPS data with a MacBook or iPad. when out and about. I know GPS is one of the selling points of the cellular iPad but I would have thought the major reason people buy those is for mobile data. Navigation apps would look great on a larger iPad screen.
     
  2. rorschach macrumors 68020

    rorschach

    Joined:
    Jul 27, 2003
    #2
    That would definitely be possible for a third-party app to implement. Remember, Continuity is an API and not just limited to Apple apps. :)
     
  3. iolinux333 macrumors 68000

    Joined:
    Feb 9, 2014
    #3
    Are you sure it's not there?. If I just do regular tethering of Wi-Fi from my iPhone to my iPod, my iPod receives GPS data over the Wi-Fi connection. It even did this in iOS 7.
     
  4. ZEEN0j macrumors 6502a

    Joined:
    Sep 29, 2014
    #4
    This is true. But doesnt it only update once every minute or something? I might remember it wrong.
     
  5. HolyGrail macrumors 6502

    HolyGrail

    Joined:
    Nov 21, 2010
    Location:
    Planet Earth
    #5
    Its receiving Cell Tower Data, not GPS.

    GPS is much more accurate.
     
  6. iolinux333 macrumors 68000

    Joined:
    Feb 9, 2014
    #6
    Wow I was very mistaken. I really thought the GPS data stream was pushed through an ad hoc connection between iDevices
     
  7. iolinux333 macrumors 68000

    Joined:
    Feb 9, 2014
    #7
    I just checked again. I was not mistaken. IDevices definitely get GPS data over the ad hoc connection to an iPhone in real-time. I don't know if OS X receivea this data however.
     
  8. HolyGrail, Nov 9, 2014
    Last edited: Nov 9, 2014

    HolyGrail macrumors 6502

    HolyGrail

    Joined:
    Nov 21, 2010
    Location:
    Planet Earth
    #8
    You're getting A-GPS or Assisted GPS. Its not the same. Wifi ios devices can only use A-GPS, while cellular ios devices have a deticated GPS receiver, and can use both A-GPS and GPS.

    Here is a good read on it.

    GPS

    GPS satellites circle the earth twice a day in an orbit. These satellites continuously send information to the earth via radio waves. Messages transmitted by the satellites include (a) the time the message was transmitted, (b) the ephemeris or the information about the orbit, and (c) the almanac or the health and rough orbits of all the satellites. GPS receivers use these signals by calculating the time at which the signals were sent by the satellites and time at which they were received on Earth. Once the GPS receiver knows the position of at least four satellites and the transmit time of each (this is called time to first fix), it is able to lock its own location. This method of computing is called trilateration.

    It may take 3 sec to a couple of minutes to get the signal depending upon the location and amount of interference. Interferences may be because of the terrain or number of buildings, foliage, atmospheric inconsistencies etc. This would result in signals reflecting off and having multiple paths.

    A-GPS

    Now, in case of an A-GPS device it uses the existing servers for e.g. of the mobile network tower and bases to get the information from the satellites. Since these servers are continually sending and receiving information there is no delay in knowing the exact orbit and time location of the satellites. In other words the time to first fix is a lot faster than a normal GPS. Also these servers have good computation power so they can analyze the fragmentary signals received from the GPS receiver and those received directly from the satellite and thus correct the error. It will then inform the receiver its exact location.

    On the other hand, an A-GPS device uses existing servers e.g. mobile network cellsites to get the information from the satellites. Since these servers are closer and better connected to mobile devices, and are continually sending and receiving information, there is no delay in knowing the exact orbit and time location of the satellites. In other words the time to first fix is a lot faster than a normal GPS. Moreover these servers have good computation power so they can analyze the fragmentary signals received from the GPS receiver and those received directly from the satellite and thus correct the error. It will then inform the receiver its exact location.

    A-GPS is faster in finding the location but GPS gives a more precise location information and another advantage is its ability to lock on directly to the satellites. While there is no additional cost involved in using GPS devices, an A-GPS has additional cost involved because it uses services and resources of the wireless carrier's mobile network. Some A-GPS models have the ability to link up to GPS satellites directly in case the assistance server is not available or if it out of cellular network coverage area, but GPS devices cannot log on to a cellular network.
     
  9. iolinux333 macrumors 68000

    Joined:
    Feb 9, 2014
    #9
    I'm well aware of the difference, thanks, I was getting into GPS before the first satellite was even launched. It's not aGPS. It is real-time satellite GPS data, there are numerous apps you can check this with. Altimeter+ is one. I'm pretty sure it's free.
     
  10. Phil A. Moderator

    Phil A.

    Staff Member

    Joined:
    Apr 2, 2006
    Location:
    Shropshire, UK
    #10
    @HolyGrail - A-GPS is simply a way to get a quicker "first fix" position - it still uses GPS satellites and is still "real" GPS. You seem to be confusing A-GPS with cell tower triangulation and Wifi positioning (neither of which use GPS chips)
     
  11. HolyGrail, Nov 9, 2014
    Last edited: Nov 10, 2014

    HolyGrail macrumors 6502

    HolyGrail

    Joined:
    Nov 21, 2010
    Location:
    Planet Earth
    #11
    Phil I'm not saying it itsn't GPS. I'm saying its a limited GPS, which is streamed to the wifi model.

    I'm just simply trying to point out that when you tether to an wifi Ipad and you get location services, it not the same as having a dedicated GPS receiver that is in a cellular ipad or iphone.

    iolinux333 if you think you're wifi device is somehow using the GPS receiver from the device you are tethering, you would be mistaken. You're using network towers to get the information from the satellites which is A-GPS.


    If you like, we can forget the tech mumble jumble behind it, and if you want real world results, I can make a video of a wifi Ipad tethered, and a cellular one with a GPS receiver on a comparison drive so you can see the difference.
     
  12. Julien, Nov 9, 2014
    Last edited: Nov 9, 2014

    Julien macrumors G3

    Julien

    Joined:
    Jun 30, 2007
    Location:
    Atlanta
    #12

    Not sure about paring a GPS signal through a hot spot ( I have a cel/GPS iPad) but A-GPS is regular satellite GPS with an advantage. All iPhones and cell/ iPads use A-GPS. The main advantage A-GPS has over GPS is GPS takes time to lock onto 3 or more satellites, especially if you change locations since last lock. A-GPS uses cell tower triangulation to 'jump start' your current approximate location until GPS gets a good lock and fixes your position.

    EDIT: Disregard my edit.
     
  13. HolyGrail, Nov 9, 2014
    Last edited: Nov 9, 2014

    HolyGrail macrumors 6502

    HolyGrail

    Joined:
    Nov 21, 2010
    Location:
    Planet Earth
    #13
    Ok, but you need both. A-GPS is a jump start as you put it, but a wifi ios device shows you're approximated location, it doesn't have a GPS receiver to lock the satellites.
     
  14. deeddawg macrumors 604

    Joined:
    Jun 14, 2010
    Location:
    US
    #14
    Again, wifi-only iDevices do not have a GPS chip and thus cannot directly utilize any sort of GPS, whether it be A-GPS or non-assisted GPS.

    Please stop associating the two, it'll only confuse other readers.

    wifi-only have NO GPS capability. None. At all.

    They DO have wifi positioning capability, and when tethering to a GPS equipped device the GPS location may be conveyed, but there remains NO gps capability in the wifi device.
     
  15. Gav2k macrumors G3

    Gav2k

    Joined:
    Jul 24, 2009
    #15
    Ok let's be 100% clear on this. The gps data is not passed on through normal tethering. The iPad can get its location via various wifi connections you pass. If you are out in the wilderness however you'll find the iPad will be very spotty.

    There is a solution though.

    AirLocation by Kai Aras
    https://appsto.re/gb/v1gLz.i

    The above app will pass the information from your phone to iPad ;)

    I'm not saying to use the app. What I'm saying is it's possible
     
  16. HolyGrail macrumors 6502

    HolyGrail

    Joined:
    Nov 21, 2010
    Location:
    Planet Earth
    #16

    Uh...why are you quoting me? Did you not read this thread? If you look up the thread you will see that I've been explaining the wifi doesn't have a GPS Reciever, and that it only receives A-GPS from cell towers. Before you try an correct someone, you should try to read what was said in the thread so you don't quote the wrong person.
     
  17. deeddawg macrumors 604

    Joined:
    Jun 14, 2010
    Location:
    US
    #17
    This is 100% completely and totally dead wrong.

    That's why I posted.

    No GPS receiver == No GPS
    No cellular hardware == Receive nothing from the cell towers

    I'm not even sure the old form of aGPS even exists anymore (where calculation is offloaded), every current phone I know of has an actual GPS chip built in. They'll still get the ephemeris and time/date over the cell network for faster fix and help in low-signal areas.
     
  18. HolyGrail, Nov 10, 2014
    Last edited: Nov 10, 2014

    HolyGrail macrumors 6502

    HolyGrail

    Joined:
    Nov 21, 2010
    Location:
    Planet Earth
    #18
    Wait....wait.....are you seriously tying to tell me that when you connect or tether a wifi idevice that location services is not using cell towers to determine you're approximated location?

    Really now? Please.....oh mighty genius, let us all know when you connect or tether to you're wifi ipad how it gets you're approximated location then, if not from cell towers?

    I clearly stated, but you refuse to read or comprehend. "A wifi Idevice doesn't have a GPS Reciever, and that it only receives A-GPS from cell towers...............Key point there, as in cell towers receives GPS then sends that information to you're phone that is tethered to you're wifi ipad to determine you're approximated location on you're ipad....A la Assisted GPS.


    Waiting for this great answer.
     
  19. Julien macrumors G3

    Julien

    Joined:
    Jun 30, 2007
    Location:
    Atlanta
    #19
    That is not A-GPS. Cell tower triangulation has nothing to do with GPS. Cell towers don't recive or send GPS info to yor device. Cell towers don't use satallite data. You have a miss understanding of A-GPS.

    A-GPS uses the GPS reciver in the device (iPhone). The A is when the device suplements it's GPS data with cell tower triangulation.
     
  20. HolyGrail, Nov 10, 2014
    Last edited: Nov 10, 2014

    HolyGrail macrumors 6502

    HolyGrail

    Joined:
    Nov 21, 2010
    Location:
    Planet Earth
    #20
    Then explain, when you connect or tether to you're wifi ipad how it gets you're approximated location then, if not from cell towers, Wi-Fi positioning system, or A-GPS?
     
  21. iolinux333 macrumors 68000

    Joined:
    Feb 9, 2014
    #21
    I'd actually like to see that. Look I'm not one million percent sure but I have both devices in front of me, an iPod 5 and and iPhone 5, iPod tethered to iPhone, and they show the exact same elevation data and location data. If I turn the tethering off and connect to regular home Wi-Fi the elevation data goes away.

    ----------

    I installed Co Pilot on my iPod. It's tethered to my iPhone. Under settings/GPS it shows 3D GPS FIX ACQUIRED gives exact location to six decimal places matching my iPhone and exact elevation. If it's doing this off of stray Wi-Fi signals then we may as well shut down the GPS satellites and save the taxpayers some money.
     
  22. HolyGrail, Nov 10, 2014
    Last edited: Nov 10, 2014

    HolyGrail macrumors 6502

    HolyGrail

    Joined:
    Nov 21, 2010
    Location:
    Planet Earth
    #22
    Sure. I can get a comparison video up. Should be around tomorrow afternoon. I see there is a free Co Pilot, so I'll use that, Apple and Google maps.
     
  23. chabig macrumors 68040

    Joined:
    Sep 6, 2002
    #23
    As has been said, a wifi only iDevice has neither GPS nor cellular radios. Therefore it cannot receive GPS signals from satellites nor cell signals from cell towers. It estimates position based on the wifi networks it detects.
     
  24. deeddawg, Nov 10, 2014
    Last edited: Nov 10, 2014

    deeddawg macrumors 604

    Joined:
    Jun 14, 2010
    Location:
    US
    #24
    Yep, pretty much. You clearly haven't an understanding of what constitutes AGPS and thus you're spouting nonsense as if it were the gospel truth.

    Via wifi location of wifi hotspot it can see even if not connecting. Described previously.


    ... and again you don't comprehend what AGPS is. Not to mention your conceptualized model is kind of silly; if the tethered connection is smart enough to somehow pick the cell tower location from the tethering cell phone, why not just get the actual cell phone GPS location since it's a very rare cell phone without a GPS chip.

    You're just thrashing in your attempt to not be wrong. Step back and apply rudimentary logic in lieu of your histrionics: (a) How does the iPad know what it's tethering to? (b) what protocol in a TCP/IP connection provides GPS information from cell towers as well as direction and signal strength to allow for triangulation? (c) what protocol in a TCP/IP connection provides GPS coordinates data from the phone?

    Item (c) is certainly possible, and would make sense. It's not AGPS however, which is the basis of your argument. Testing to see if an tethered wifi-only iPad can get a good location actually is more in favor of (c) than it is of (b).

    For your next post, instead of bold face type, ad hominem attacks, and font size modifications, how about you post actual information and citations of real sources to back up your argument?

    Shouldn't be difficult since you think I'm so utterly and totally wrong. :)
     
  25. HolyGrail macrumors 6502

    HolyGrail

    Joined:
    Nov 21, 2010
    Location:
    Planet Earth
    #25
    Yeah.......I know. Ergo my original post.

     

Share This Page