iPad Navigation
You are correct, the iPad's built in GPS doesn't function without an internet connection, so you will need a GPS antenna. Beware, the iPad uses a different GPS protocol so you need a compatible antenna. The ubiquitous NMEA bluetooth receivers from e-bay at £25 or so won't work. Harry M used to stock compatible GNS GPS receivers for around the £60 mark. Sky Demon's charts sit in the iPad's memory so do not need an internet connection. The internet connection is only used to download the weather and the notams. Strangely however, my wifi only iPad updated the notams whilst in flight earlier this week. I must have flown over a wifi hotspot! db