Dave,
thanks for your reply! You’re absolutely right with your comments about the “sphere” problem, yet, the closer you are to a sphere, the more you can neglect it’s round shape (as a long time private pilot I would never worry about the earth’s round surface when setting up a navigation plan for a 50 mile trip 😉
The aerials cover a range of about 10 x 5 miles and the idea was (or still is 😉 to write a script that translates the NMEA data into the AE grid in order to show the actual position of the helicopter on a map. But before trying to write such a script, we need to re-convert the NMEA audio signal into readable positioning data…
Thomas