TB is, maybe on purpose, confusing GPS which is an accurate location system with applications that use the location data. There is no doubt about the accuracy and repeatibility of GPS data. Those in the US will be familiar with its original purpose.
What I hoped for here is an honest debate. Trying to derail a debate with talking points is too much like politics, not science.
I think the debate should just be on "flat earth" and not a debate on "flat earth-vs.-round earth."
Then stop bringing up things that rely on the Round Earth model being accurate or true, because we are obviously not going to accept the accuracy of the distances between points on a Round Earth coordinate system unless those distances are demonstrated to be accurate.
Which was done at the start of the thread, and you've been looking for how to deny that ever since, taking us frequently off track.
We showed you how the speed of an airplane is known, and that with that and flight times we can deduce the distance traveled. Then showing how those distances can't work on a flat Earth.
You took issue with how we know the speed of an airplane. 3DGeek explained how we know it's speed through rigorous math, science and testing before the plane ever leaves the ground. As well how a plane can get it's speed without measuring against the ground in any way.
You latched onto the GPS explanation for how those can't be accurate because of all the people posting online that they aren't accurate for their walks. We've shown you that there's a difference between consumer grade GPS, and the high end ones that are accurate with distances to millimeters.
You continue to say we can't trust them because of all these reports of inaccurate measurements. Claiming you don't see the parts that reference the accuracy of higher end models, and can't seem to understand how position error can result in distance error when tracking a person walking.
Then simply revert to saying we can't trust anything based on a RE coordinate grid, because it's based on a RE coordinate grid. Ignoring the fact it works, ignoring the testimony of people in the airplane industry who say their instruments couldn't work if the Earth was flat and the software was supposing a round Earth, and ignoring most offers and requests to give a method of confirming distances that you would accept.
For a supposed expert and very vocal proponent of FE, you certainly show a surprising lack of knowledge about either FE or the workings of RE. I suppose that can explain why you follow it so vehemently. You don't appear to understand how anything works in either model beyond the most basic concepts.