Yes, you are right. The iPad built-in GPS can be used as the GPS source. Using in this way you need to keep your iPad outside all times. Otherwise, you will lose GPS signal(no GPS signal in the building/room). I would suggest you have an AS04 in case you lost the build-in GPS signal. One point please be aware: since you have two independent GPS sources, sometimes you maybe see your position jump a little bit. This doesn’t happen very often, most navigations software/apps have a smart algorithm to smooth this tolerance. We didn’t see this issue with our tests but some customers have reported this before.