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PracticalMac

macrumors 68030
Original poster
Jan 22, 2009
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Houston, TX
aGPS in all cellular equipped iPads use the cell network to download a tiny positional data file (GPS Almanac and Ephemeris) for faster acquisition of satellite data.

Do you need cell service to do that, or is it free? (like calling 911 on any cellphone out of contract).
 
Last edited:

moonman239

Cancelled
Mar 27, 2009
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Intell is correct. However, Maps uses the Internet connection to download information about the place you search for and to calculate directions. Absent a data plan, you'll have to use an app that stores navigational data on your iPad.
 

takeshi74

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Feb 9, 2011
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Do you need cell service to do that, or is it free? (like calling 911 on any cellphone out of contract).
Cell service is needed for aGPS to download ephemeris data for a faster initial fix but the aGPS receiver can fall back on standalone mode without cellular coverage. Cellular coverage is not needed for a GPS fix. If the assistance servers are not available for the ephemeris data download than the aGPS receiver will get a GPS fixout without. It will just take a bit longer.

However, Maps uses the Internet connection to download information about the place you search for and to calculate directions. Absent a data plan, you'll have to use an app that stores navigational data on your iPad.
Maps isn't the only GPS app that relies on data. Any GPS app that relies on data will have problems. Some GPS apps have locally stored maps but have other features that rely on data (traffic, etc). Obviously, those features will not work without data coverage.
 

PracticalMac

macrumors 68030
Original poster
Jan 22, 2009
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Houston, TX
Cell service is needed for aGPS to download ephemeris data for a faster initial fix but the aGPS receiver can fall back on standalone mode without cellular coverage.

Yes, need to be in a coverage area, but the data can be downloaded without need of contract (read link couple posts up, found after a lot of searching).

At least that what article states.
 
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