Assisted GPS does not require a data plan or cell connectivity to work . . .assisted GPS means that the GPS chip uses cell tower info as a starting point to get a fix. Without it . . .the GPS receiver must do a great deal more analysis of the orbital ephemeris of the satellites before I can determine where it is.
My iPhone gets a fix just fine with 3G and data disabled. Note though . . .that putting the iPhone in airplane mode is not the same . . .that disables the radio entirely which means that the receiver is turned off as well. If you've got a GPS in your car . . .ever notice how it gets a fix much faster if it is in the same location as it was when you turned it off compared to turning it off in say Jacksonville when you turned in the rental car . . .and carrying it in your pocket to Atlanta and turning it on in your next rental car? Takes much longer in the second case . . .the receiver attempts to use it's last known location as an assist just like it does with cell towers. If they aren't available, or the last known position is hosed . . .the receiver is forced to listen a lot longer to the info the satellite is transmitting before it has enough data to find itself. On Feb 4, 2010, at 3:59 PM, objectwerks inc wrote: > > > Of course, that begs the question of whether the GPS works without a data > plan. It is billed as some sort of assisted GPS that is built into the G3 > comms chip. I think on the iPhone that the GPS gets seeded by a cell tower > triangulation first. Don't know the details. ----------------------------------------------- There are only three kinds of stress; your basic nuclear stress, cooking stress, and A$$hole stress. The key to their relationship is Jello. neil _______________________________________________ MacOSX-talk mailing list [email protected] http://www.omnigroup.com/mailman/listinfo/macosx-talk
