Your assumptions are incorrect. I am a well trained and experienced engineer and wouldn't be fooled for long. The combinations of the speed of light, azimuth, and elevation in combination with knowing where our ship is at all times would make it impossible to fake a geosynchronous satellite with any kind of a balloon, dome, or anything else. I've been thru this argument before. No one has ever been able to come up with a design of a system that would emulate a geosynchronous satellite system on a flat earth platform that would respond to all the combinations that I would see on a daily basis. If you have a viable design than the FET folks would really like you to post it for everyone to see. While you are at it, show all the professional seamen out there just how celestial navigation would work on a flat earth. Yes, we use GPS just about all the time, but everyone has to know how to use a sextant and the navigation tables to fix our position in an emergency. That whole system is based on spherical geometry on a globe. it works, and has worked for 100's of years. There's no theory there, it just works every time it's tried.