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Which Model to Buy? iPad 2’s Assisted GPS Demystified

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There seems to be quite a bit of confusion online about what exactly “Assisted GPS” on Apple’s iOS (s aapl) devices is, especially regarding navigation-based app requirements. It can be a bit complicated, but understanding what it means could help you decide which iPad to buy.

For developers, the Core Location Framework in iOS can use the onboard GPS, cell, or Wi-Fi radios to find the user’s current longitude and latitude. Each one has a different degree of accuracy and uses a different amount of battery life.  This abstraction allows developers to write code without exactly knowing what capabilities the iOS device has available to it.  So, for the most part, developers don’t always have strict requirements where GPS capabilities are concerned.  But as a consumer, you want to know exactly what you’re getting for your money.

Wi-Fi iPad 2 and iPod Touch’s Wi-Fi Database

According to the tech specs for the iPod touch, this iOS device has what is referred to as “Maps location-based service”.  This means that the user’s longitude and latitude are determined based on their proximity to known Wi-Fi networks.  Since iOS 3.2, Apple has claimed to be using its own databases to provide such location-based services.  So we know that the iPod touch and the Wi-Fi only iPad 2 aren’t using GPS, but what about the iPhone 4 and 3G-capable iPad 2?

Wi-Fi + 3G iPad 2 and iPhone 4’s Assisted GPS

With GPS devices, the assisted terminology refers to the fact that the resulting GPS data is enhanced.  Under certain conditions, this enhancement can speed the start-up time to get an initial location fix faster.  So the same technology that’s used in the iPod touch to determine a user’s location based on Wi-Fi proximity is being used on the iPhone and the Wi-Fi + 3G iPad 2 to assist these devices in getting that initial fix.  The tech specs for the iPad 2 claim that only the Wi-Fi + 3G model has this “Assisted GPS” feature, and this is the same feature found on the iPhone.  The Wi-Fi only model of the iPad 2 does not have this feature.

What Good is GPS on an iPad Beyond Online Maps?

While it is certainly true that the built-in Maps App is pretty much useless without data connectivity, there are an increasing number of apps that will either cache, install or download maps for offline access.  MotionX GPS HD for US $2.99 in the App Store has what is likely to be one of the better implementations of downloading maps at a very reasonable price.  GPS also means you’ll have more accurate results when using location-based recommendation or social networking apps. It’s not something that everyone needs, but as it becomes more and more popular, it could represent a significant upside to owning an iPad, so consider the benefits of assisted GPS when making your choice.

31 Responses to “Which Model to Buy? iPad 2’s Assisted GPS Demystified”

  1. I intend to get an Ipad 2 for use in aviation using software such as Foreflight HD. If I do not intend to activate a carrier, does GPS performance (including A-GPS) differ between the Verizon 3G units and the AT&T 3G units? One area of question is flying out in the desert southwest where there tends to be better Verizon coverage than AT&T coverage. Would that imply that a Verizon iPad 2 (even unsubscribed) might have better A-GPS than the AT&T iPad 2? Or does the non-subscribed GPS work the same in either the Verizon or AT&T units?



  2. My cousin just had her Ipad stolen and the thief is posting things to her facebook page. Is there a way to track that Ipad? I submitted this earlier, but I don’t see it and I forgot to check the notify me of follow-up comments via email box. So I’m commenting again. Also I’m not sure what to put in the site box.

  3. My cousin had an Ipad, I’m not sure what model, but it was stolen. Is there a way to track it? Whoever stole it is posting stuff on her facebook page.

  4. henry vme

    With GPS Kit from Garafa you can manually store (free) maps from Google, Bing or Open Street on your iPhone/Pad at home and use them later without any network. This app is not cheap, 10 $, because it’s a complete GPS tracking app with lots of features you may not use, but you never have to pay for a map ! It saved my stay in Beijing !

    • I have played around with the design option that GPS Kit uses to off load maps and have found the user interface of MotionX GPS to be much, much easier to use. Currently GPS Kit on my iPad 2 crashes every time I try to download maps. I also use each of these apps on my old iPhone 3G that no longer has a data plan. It us now a quite useful and very GPS device. I even use TomTom on the old iPhone and the turn by turn works very well. TomTom also works on the iPad with 3G, but since it is not an iPad or a universal app, I did not recommend it in this article. MotionX is the best option for the iPad right now.

  5. I just got a new ipad 2 wifi only and the map application pinpointed me to exactly the same location as my iphone 3gs. It sure seems like there is a gps in here.

    • Hmmm… this is getting very confusing now! And you were at home or something, not at a specific “known” wifi-spot?

      Can more people acknowledge this?

      • Yes. I’m at home. It’s in a rural area. Phones without GPS for instance are not particularly accurate since there are not too many towers around. (That wouldn’t apply to this anyhow.) I’ll see what happens later today when I leave the house. If it tracks my movements untethered, then we’ll know more.

      • I bought a wifi only iPad 2 yesterday and have been at home on blazing fast wifi ever since. The maps application refuses to pinpoint me. There is certainly no GPS capability in the Wifi only iPad and for me, very disappointing that triangulation is not working. My 2g iPod touch can pinpoint me at home but not my iPad 2 wtf?

      • The Wi-Fi only model can locate your position IF you are near a known Wi-Fi access point that Apple has in their database. Basically the database ‘assumes’ that Wi-Fi access points in the database are at and will forever remain at fixed locations. This ability to know your location on the Wi-Fi only model is not using GPS satellites to pinpoint your location. Only the 3G model had the GPS receiver built in that can pinpoint your location using radio signals from GPS satellites.

      • Agreed. There is no GPS capability but the wifi location service works very well. Even riding around in a rural area, it tracks pretty well. This is even though it is not actually connected to a wireless network and no commercial wireless access points around. Of course, the map data dissapears after a while…

      • What you did with the iPad 3g without a data plan or a sim-card inserted is still not perfect. To really know if the GPS works precisely without a data plan, you have to move somewhere were there is no cell phone net cause the iPad even communicates with the cell phone net when there is no sim card inserted. That’s why you can make emergency calls even w/o a sim card. I want to sail across the Atlantic ocean and still don’t know if the iPad can get precise positions w/o the cell towers.

  6. Numerous apps use location services to enhance their features. Astronomy apps like Planets use it to tell what location you’re looking up from. Emergency Radio can use it to show you radio feeds centered around your location. In Seattle, the marvelous OneBusAway can show you nearby bus stops on a map as well as when buses will actually arrive, usually accurate to about a minute. That beats standing in the drizzle.

    In general, if you travel, there are apps that can use your location data to advantage. I’m not sure why Apple doesn’t begin to ship GPS will all their mobile devices, including the laptops. It’d be a great selling point.

    A few times, my GPS lock-in has gone slow enough to suggest what may be happening. First, there’s a huge, half-mile wide circle with the location perhaps derived from cell-tower data. A few seconds later, the circles shrinks to a 100 yards or less based on WiFi data. Only later with satellite lock-in does a GPS accuracy rating appear.

    It’d be great if there were a technical app that displayed all this information: 1. The nearby cell towers and their location. (My Kindle 1 can do that.) 2. WiFi sites and their assumed location. 3. The number and sky location of the GPS satellites being used. But I suspect only Apple could get to that information and they seem to have a phobia about any app that might reveal the iPhone’s complex innards. Everything’s supposed to look like it works by magic.

    • Yes, there are lots of location based apps. But I was focusing on location based apps that did not need to be connected to the Internet. Justifying the purchase of a 3G model solely for it’s GPS capabilities.

  7. David Chilstrom

    Assisted GPS on the iPad also uses cell tower triangulation for a more precise initial fix than is possible with Wi-Fi alone. If one has a cell data account, Google maps should be available wherever you have coverage. Also, Find my iPhone/iPad is even more useful with an iPad 3G. And, of course, beyond maps, there are a plethora of location based apps that will benefit from the precision of GPS.

  8. “…MotionX GPS HD…one of the better implementations of downloading maps”
    The last time I used it (Sept. 2010) it was still dependent on AT&T to load maps while driving, not a good solution in many areas of the country. If you can now purchase/download US maps ahead of time, that’s (good) news to me.

    WHat I don’t understand though — where is TomTom and other leading GPS programs for the iPad? What is taking them so long?

    • You need to make sure that the maps you have set to view are of the type of maps you have downloaded. Meaning that if you download road maps, but are trying to view satellite maps, it won’t work when off line.

      This has been working perfectly for me, exactly as described, on the iPad 2 since I got it earlier this evening.