A year ago today I launched something similar, but for Great Lakes boats passing my house on the Detroit River (uses AIS rather than ADS-B, and passively tracks the boat crossing the fixed camera rather than pointing the camera):
I'm using fuzzy subsets of Euclidean 3-space to model sensor coverage. Computationally, I use FuzzPy's (discrete) fuzzy set class to make fuzzy sets of 3D point objects to work with.
https://twitter.com/detroitships