The government can't control the speed of light, so that means that no matter what the offset is the time measured by recievers will change with distance as expected. If you get an additional 10 feet away from the transmitter then the receiver cannot be tricked into thinking that the change is anything other then 10 feet. That is where the probelem lies.
I'm not blaming the government, just a few administrators and engineers at space agencies.
They don't need to change the speed of light, just the speed of the transmission. Add a few 'pause' markers between the landmarks the GPS uses to interpret the data, you'll get the same effect.
This is because the way that the distance from satellites changes as you go across the surface of the Earth is something that's highly sensitive to the shape of the Earth. I could provide diagrams and graphs to prove my point of you want.
Distance from airplanes, balloons, helicopters... will change as you go over the surface of the Earth, even on a FE. To my knowledge, multiple satellites are used to gauge position: not just one or two for the globe. Curvature shouldn't be too major a factor if the nearest satellite is used.
What the is the "offset model"?
This may be why you later express difficulty in understanding what I'm saying: you're coming in, in the middle of a conversation. It's never going to be clear what's going on them.
As was explained earlier, GPS reportedly works by data being emitted by satellites, and the GPS expecting certain data, and measuring the difference between the two: the delay in receiving the signal is how distance is measured. The offset model supposes the signal comes from lower transmitters, which are 'offset': the data the emit is a little ahead of the GPS, thus giving the illusion the signal comes from higher up.
This has all been explained, and as such directly answers your question. Please don't enter into the middle of a conversation without reading what's been written before. Maybe you're unsatisifed with my answer, but for your query mean anything you should at least be able to understand the model that I am referring to, and have been outlining throughout this thread. The fact is you haven't even tried to understand what's being discussed, you openly ask about the basics of the conversation we're having clearly showing you have not even begun to read the conversation. I take quite an issue with your insulting tone for this reason because it is clear you do not know what you're talking about.
If you have a problem with my model, you should at least know what the modle is; you should have at least read about it rather than blithely assuming that just because I am a flat Earther I must be incapable of answering the most basic questions posed (and did you really think you were the first and only person to ask those questions, or for that matter that I would blithely mention a mysterious offset model and that only you would be bothered by that?)
Please read a conversation before chiming in.
Instead of talking in riddles, if you have an alternative system, then draw a diagram and take us through how it would work, step by step.
This is once more something I have done over the progress of this thread.
Imagine a satellite. Its signal is sent down to the Earth.
Now, pick a certain altitude, and place a transmitter at that altitude intersecting the satellite's signal: as the signal must be predictable if it is to be interpreted, have that transmitter emit the same signal. Remove the satellite, the same signal will reach the GPS unit on the Earth: offset timestamp to give the illusion of duration, and a similar effect. Having more than one of these for an area would remove most, if not all, error.
For a final note, which you would also know had you read the conversation, I do not believe this. I do favor the hypothesis that space travel, including satellites, are genuine.