Recent content by Suxxor

Thanks. This is proof that a normal GPS receiver would determine the position accurately even if clock frequency on satellites wasn't corrected, because a normal receiver uses at least 4 satellite signals so equation 5 in the paper applies (the term Δ in equation 5 is calculated independently of...

The 'distance = speed X time issue' has been considered before in this thread: https://www.physicsforums.com/showthread.php?t=543848#13 The systematic error would be in a region of 1 cm. So GPS would still work as well. Do you agree that, given that Earth-time is not used in position...

I went through the project, pointed out a contradiction (post #21), which you discarded as nonsense. Your posts in this thread do not lead anywhere. We all saw your point, but sadly you are not able to see ours. I did not try to 'mine stuff', just make you understand our argument. If you could...

On the same slides, he has written "... reference clock is on Earth equator". But in GPS system, reference clock is on one of the satellites, not on Earth equator.

That's correct. Not necessarily. Since 4 satellites are used, planetside clock is eliminated from the equations; chingel's post proves that.

Are you winding me up? Are you serious? I cannot believe it. It doesn't matter how big the time drift between ground and satellite is as long as there is no time drift between satellites themselves, error would not accumulate.

You are still not getting the point. I don't think it can be explained more clearly than chingel and Passionflower have done in posts #28 and #29. I would not mind getting adequate counter-arguments, but this is getting frustrating. Nevertheless, I'll try explaining one more time...

We are arguing whether GPS positioning would work if relativistic time drift in satellites wasn't compensated. One camp is saying that the position error build-up would be 38 000 feet per day (without compensation). The argument is based on the fact that ground clock would go out of sync with...

But ground based clock is not used at all! How can it cause an error then? You have missed the point. It is not. Several posters in this thread have understood the issue: #8, #9, #15, #16 . The problem is, you have not understood the argument, but rant at me claiming I talk nonsense. If...

Who is saying that? No-one is saying the system would fail 1 foot/ns. Some sources and Brian Cox is claiming the system would fail 38 000 feet per day which is not the same as 1 foot per ns. 1 foot/ns is the speed of light and means that 1 ns desync between GPS signals means approximately 1...

Did you use smaller font for all the reasoning to back up your argument? Because I cannot see any. To prove your point, you'd have to give at least some - in particular show that the two simple calculations in post #13 are wrong, incomplete or based on the wrong assumptions. Even Einstein...

x = 20200 km = 20 200 000 m (approximate height of the orbit) c = 3 \cdot 10^{8} m/s \Delta \tau= 38 \mu s / day = \frac{38 \cdot 10^{-6} s}{24 \cdot 60 \cdot 60 s} = 4.4 \cdot 10^{-10} s/s (relativistic time drift on satellite compared to ground; taken from literature) t_{without...

BTW, the paper describes the relative time shift between orbital and ground based reference frames (pages 15, 16), but does not state how the GPS position error would have behaved, if clock frequency wasn't compensated according to EQ 36. It could be that the compensation was put to place to...

Thanks. That is precisely what I meant. It seems that the huge position error accumulation estimate of 38000 feet per day is nonsense, because it is based on the assumption that receiver uses absolute local time, thus error accumulates. Whereas in reality receiver resets it very frequently using...

Yes, pretty much. Actually I was trying to say that the 38000 feet per day position error drift estimate, if the relativistic effects weren't compensated, is wrong. The error would never accumulate like that over time. But is this reasoning justified?