My understanding, please double check with Apple, is that iPads primarily use AGPS (assisted GPS) which is based on triangulation of the cellphone towers near the device. However, if it is 3G/LTE then it is supposed to have native GPS if you turn off all other connections (not airplane mode, but the actual cell, wifi and bluetooth connections).
I use an old wifi-only iPad Mini for navigation and purchased the BadElf GPS puck, it works well. I run Garmin and Topo apps for on and off-road adventuring, I also run a wireless OBD-II connection to monitor all the data from my engine since the E-150's gauges are horribly simplified and don't show much data.