On a recent trip with friends, I was able to test the GPS capabilities of three tablets: two Ipads (1) Ipad2+3G with no active cellular phone subscription, and (2) Ipad mini with no 3G. Both were tested with the IOS 6 version of the 'Maps' app.
The playbook's GPS was activated with GPSMaster, and then the Osmand app was used with cached maps of the area. The comparison was carried out on a boat trip in coastal sea waters in the Gulf of Mexico, near Naples, Florida.
For the test, all three devices were cold started while traveling on water, away from potential WIFI sources, but within 3G/4G service areas. The Ipad mini, was able to track the location for about 3 km from the starting point; presumably using its built in compass, accelerometer and cached maps. Then, the location point disappeared.
Both the Ipad2+3g and Playbook were able to track location perfectly, throughout the nearshore/offshore sea journey, but the Playbook's location accuracy was much greater; often under 1.2 meters, while the Ipad's was never better than about 15 meters.
Given that the Playbook, has a built-in GPS chipset that communicates with orbiting satellites, the results for this device were not too surprising.
However, how an IPad2+3G with no active subscription, and 3G set to 'inactive' in settings, accomplishs this is more enigmatic. Can part of the Ipad's '3G, package' communicate directly with satellites, or perhaps triangulate using cell towers in a manner analogous to 911 geolocation?
Note: I am not condoning use of any tablet
as a replacement for a dedicated GPS, just interested in their technical capabilities! Also the Ipads will geolocate using A-GPS much more rapidly and inside buildings, something the Playbook cannot do, since it requires open skies to function properly.