Heres my opinion, the CRJ was used for test of accuracy at altitude using the iPad for a very reasonably priced back-up reference system. My iPad nor my old iPhone would I trust its own nav system on, for the $75 I would by the Dual system, 10 meter accuracy as shown in there app along with all satelites GS, ALT Etc. No wires with bluetooth, about 6 hrs batt life, charges by USB. So try your software without the Dual ext. GPS and if it works great if not buy the Dual. I think aviatoreb is accurate with 10K without it. I haven"t been able to try it in a GA plane yet.....still looking for a clean old Mooney C, E, F....haven't had a plane for long time. Rick