Well, in thinking about it more I think I may have figured it out. Forgive me while I think "aloud". After converting the aircraft and target locations to ECEF coordinates, you subtract them to get the vector between them. BUT that vector is only the straight line distance between the two...
Hi there. This isn't so much a math question as it is a conceptual question. I can't seem to wrap my head around the need for coordinate transformations. *Why* do they need to be done? I think I really need a picture for this, so this might not be the right place to ask, but if you can...