After having some GPS acquisition issues with my A2 controller on a BVR flight with ground station (almost didn't get back), I started looking for an IOS app that would show me information on the GPS satellite configuration. I found this "GPS Plan" app for the iPhone that was pretty interesting. (Its free or you can pay to kill the ads). It shows the number and position of the satellites in the sky above an elevation mask (default 15 deg) and has a slider which shows the changes over time. Also it shows a plot of the number of satellites visible over a specified time period, and they change more than I would have thought. If you are planning a 15 minute BVR flight, its nice to know ahead of time that the satellite count is going to 4 (as an example). Anyway, thought I would share. I haven't seen any other write-ups on this app. Search for "GPS Plan" in the app store. Best Wishes!!