Wednesday, Dec 12, 2012 at 10:00
Bill the issue is that Apple, for reasons known only to themselves, only put a GPS in the more expensive IPADs that have phone connectivity ( the Cellular versions). The Wifi only range do not have accurate location capability.
There are 2 types of maps. Things like Google maps, apple maps and a few others need phone reception to download the maps.
Then there are raster maps like Oziexplorer, Memory Maps, Mud maps and most off road maps that have pre loaded maps ( that you do at home). They do not need phone reception, but in an apple device, they do need the phone version, even if you don't have a sim inserted and no service.
Also there is a lot of confusion about A-GPS or assisted GPS.
This simply means the device can take it's position by phone signal triangulation, ip address allocated location ( low accuracy) or by GPS or both.
The main advantage of an A-GPS over a straight GPS is that it works indoors, and for some simple location apps you don't need to turn the GPS on, saving battery. An A-GPS will also speed up location in some circumstances when the devices has moved considerably ( hundreds of km) from the last known position, though in practice this is usually marginal except for initial turn on or after many months of non use.
When thre is no phone service an A-GPS will revert to normal GPS mode just like any normal Garmin, Magellan etc GPS. I understand that an IPAD's GPS reception sensitivity is ok but not great. The main issue however is that being internal, the antenna is often under a steel roof of a car and you miss several sats causing lower performance.
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