Previous 1 2 3 4 5 Next 73 Replies Latest reply: Oct 22, 2008 1:14 PM by Zizone Go to original post
  • D.R.C. Level 2 Level 2
    Photos for Mac
    I tried the force-quit trick on the Maps app. Good idea, but it made no difference - my GPS is still dead.

    We have some cloud cover from Ike, and are expecting heavy rain tomorrow. However, I tried my Garmin nuvi side-by-side with the iPhone, and the nuvi had no problems acquiring lock. (I'm sure the nuvi has a better antenna and more sensitive front-end than the iPhone).
  • D.R.C. Level 2 Level 2
    Photos for Mac
    Your statement that the iPhone doesn't do GPS (using satellites) is incorrect. The iPhone most certainly has an on-board GPS receiver. If it is able to acquire enough sat signals, it will provide a high-resolution location fix to the Maps application and to any other apps that request Location Services.

    If it can't get GPS signals from the birds (or is running V2.1), it will attempt to determine location using nearby WiFi basestations.

    If WiFi is turned off, or if the nearby WiFi APs are not in the Skyhook location database, iPhone will estimate location using nearby cellular basestations.

    See for more information.
  • Frank1307 Level 1 Level 1
    I agree with you 100%. Since the 2.1 upgrade, I get a general idea of the vicinity I'm in via the cell towers, but GPS can't locate my exact spot.
  • Steve Hodson Level 3 Level 3
    Perhaps he has an original iPhone and is in the wrong forum?
  • v1vrv2 Level 1 Level 1
    @ D.R.C. Well thank you for lighting my bulb, I do have the new iPhone 3G and need to find out a few more things, so maybe you can tell me where I can see the satellite coverage and status on the iPhone while map is engaged and has the A-GPS running coz I cant find it, it still ask me to switch on my wifi or 3G to enable data roaming where additional fees may apply.
    As you know GPS reception is free so I wonder how it works as it doesn't seems logic although according to the indications it should work without wifi or 3G data roaming so in fact it looks like there is absolutely no control over the cost as it does it on ot's's very fine for people having at&t contract and travelling among the US but for others well...

    Well anyways if I am wrong my apologies bu will definitely accept any comment that will make me understand better how this iPhone the wy downloaded 2.1 and everything seems to work smooth !!!

    Thanks for advices !!!
  • v1vrv2 Level 1 Level 1
    By the way thanks D.R.C. reading your posts are actually helping me a bit although the time difference between you and I make it difficult but it definitely does help me to uderstand a bit more about the philosohy of this iPhone...
    And as I also have done the 2.1 update I probably have the same issue so hard for me to see how right you were with you comments for me !!!
    Well I'll stick around anyways...
  • tonytone Level 1 Level 1
    Update--FWIW I went for a drive later on that morning...GPS working just fine, as once it's locked in I get just the blue dot (no surrounding blue-shaded circle--it was showing a small-diameter shaded circle around the blue dot earlier this morning when I tried to get GPS to lock in on my location).
  • Adrian G. Level 1 Level 1
    Thanks that helped me!!! All i did was reset the settings.
  • Adrian G. Level 1 Level 1
    Thanks it worked for me!! All i did was reset all settings.
  • Hi I'm A Mac Level 1 Level 1
    Don't you love all these IT WORKS posts from those with one to three posts (apple employee's cough cough)...

    2.0.1, no way am I losing GPS, NO WAY, I use WI FI at HOME, never need 3G really, so am not messing with it.
  • D.R.C. Level 2 Level 2
    Photos for Mac

    Glad I could help.

    The A-GPS (Assisted GPS) in the iPhone is quite clever, and quite complex at the same time.

    Consumer GPS devices (such as Garmin, TomTom, etc) are totally dependent on the geo-synchronous satellites. In order to obtain an accurate fix, a GPS needs to have solid signals from preferably 3 satellites. And it needs to have available two tme-variable data tables known as the ephemeris and almanac tables. These enable the GPS device to calculate where the h*ll it is anywhere on the earth's surface. The tables are downloaded from the birds on the same radio carrier that is used for the navigation fix. If a GPS device has been turned off for some time, or has been moved geographically since the last time it had a fix, it can take some time for the GPS device to download the tables, and then figure out where it is. That's why Garmin/TomTom/Magellan devices can take several minutes on occasion to acquire lock and display an accurate location.

    The iPhone uses "Assisted GPS", which means using other resources beside the orbiting satellites to determine its location. If the iPhone has an approximate notion of where it is (using, for example the ids of nearby cell towers), it can use that information in concert with what it gets from the satellites to more quickly figure out location. In theory, A-GPS also entails using network-based servers to assist with the location calculations. If it has either WiFi or cellular connection to the internet, it could well be communicating with the cloud to help with location-finding. I don't know to what extent the iPhone does this.

    The iPhone can also use knowledge derived from nearby WiFi Access Points to glean location information. That's how the iPod Touch can do location-finding. IPT has no GPS receiver and no cellular radio, but it might still figure out location. So if an iPhone is deep inside a building (with no GPS nor cellular radio signals) but can 'see' some APs, it might be able to get a useful location fix. This capability is dependent on the APs be registered in a cloud-resident database. The amazing thing about this is that the iPhone/IPT doesn't need to be associated (registered to) the APs; it just has to be able to receive their beacon signal and decode the SSIDs (the "name" of the basestation). For more information on this bit of magic, look at

    As you can imagine, this complexity makes it quite difficult to troubleshoot issues with Location Services.

  • JJT2122 Level 1 Level 1
    I'm not having any problems 2.1 fixed all my problems even my 3g signal went from 1 bar to 5 bars and I get reception everywhere now.
  • Mark Tedin Level 1 Level 1
    I just upgraded to 2.1 and I'm having the same problem. Living in Seattle, it thinks I'm in Detroit. GPS was working fine today coming back from Camano Island. Resetting the settings didn't help at all. I'll try changing locations next and see if that changes anything. By the way, both Edge and/or WiFi give me good approximate locations (target ok but not blue pin).

  • Andrew Parmet Level 1 Level 1
    I'm having the same problem everyone else has been having with GPS after the 2.1 update. My iPhone gets the cell fix, but cannot get the tracking blue GPS dot. None of the recommended fixes have corrected the issue. Hoping for a 2.1.1 update to fix this issue ASAP...
  • Jojo00 Level 1 Level 1
    Same here. No more GPS after upgrading to v2.1. Tried all of the tricks listed here, no luck!