Is GPS consistent with relativity? (Split from is Relativity 100% proven)

[xyzt]

Since you say that you are synchronized with the main stream scientists, I accept to stop arguing,

Good.

[Skeptic134]

After reading the thread I’m a little confused at some of the responses to Le Repteux.

 

I don’t think he was attempting to say relativity wasn’t consistent with GPS. Aside from Bart, I don’t think anyone was trying to assert inconsistency in the two.

 

What I gathered was he was asking whether you could derive a correcting factor via empiricism that would account for the effects gravity has on time and thus clocks on earth and in orbit.

 

I’m not sure how the answer to that question could possibly be no considering that is part of what you do in science, find mathematical and quantitative explanations for our observations of reality.

[Le Repteux]

What I gathered was he was asking whether you could derive a correcting factor via empiricism that would account for the effects gravity has on time and thus clocks on earth and in orbit.

This is effectively another way to the same question, but that question is just a curiosity to help understand relativity, it is not a relativity issue.

[xyzt]

 

I’m not sure how the answer to that question could possibly be no considering that is part of what you do in science, find mathematical and quantitative explanations for our observations of reality.

Well, you will have to read the answers in order to understand why it is not possible to do it "via empiricism".

[Skeptic134]

That is what science is...

 

It isn't based on authoritative decree...

 

And GR isn't a catch-22 in which without first knowing GR you cannot discover GR...

 

Edited September 8, 2014 by Skeptic134

[xyzt]

That is what science is...

 

It isn't based on authoritative decree...

 

Correct, it is based on hard FACT. Something that the "skeptics" do not have.

[Skeptic134]

Correct, it is based on hard FACT. Something that the "skeptics" do not have.

 

 

Facts are repeatable observations... (empiricism)

 

So again, science is based on observations and the mathematical and quantitative derivations thereof.

 

Unless mistaken, you appear to be suggesting that GR is different than other scientific theories in that without foreknowledge it cannot be derived or discovered making it a catch-22 of sorts?

[xyzt]

 

 

Facts are repeatable observations... (empiricism)

 

So again, science is based on observations and the mathematical and quantitative derivations thereof.

 

Unless mistaken, you appear to be suggesting that GR is different than other scientific theories in that without foreknowledge it cannot be derived or discovered making it a catch-22 of sorts?

No, what gives you this idea?

I am only saying that the so-called "internet skeptics" have never contributed anything to the advancement of physics. Contribution requires knowledge of existent science.

Edited September 8, 2014 by xyzt

[Skeptic134]

The following link to Neil Ashby's 2003 paper on Relativity in GPS:

 

http://relativity.livingreviews.org/Articles/lrr-2003-1/download/lrr-2003-1Color.pdf

 

Of note:

"Also, experimental tests of relativity can be performed with GPS, although generally speaking these are not at a level of precision any better than previously existing tests." - page 6

 

"At the time of launch of the NTS-2 satellite (23 June 1977), which contained the first Cesium atomic clock to be placed in orbit, it was
recognized that orbiting clocks would require a relativistic correction, but there was uncertainty as to its magnitude as well as its sign. Indeed, there were some who doubted that relativistic effects were truths that would need to be incorporated [5]! A frequency synthesizer was built into the satellite clock system so that after launch, if in fact the rate of the clock in its final orbit was that predicted by general relativity, then the synthesizer could be turned on, bringing the clock to the coordinate rate necessary for operation.

 

Also of note is the Hafele–Keating experiment which as far as I can tell is only different from what Le Repteux was originally describbing by the clock being onboard a satellite vs an airplane.

 

Suffices to say deriving time corrections to account for relavistic effects is clearly possible and one of the ways relativity has been validated.

Edited September 8, 2014 by Skeptic134

[xyzt]

The following link to Neil Ashby's 2003 paper on Relativity in GPS:

 

http://relativity.livingreviews.org/Articles/lrr-2003-1/download/lrr-2003-1Color.pdf

 

Of note:

 

"Also, experimental tests of relativity can be performed with GPS, although generally speaking these are not at a level of precision any better than previously existing tests." - page 6

 

"At the time of launch of the NTS-2 satellite (23 June 1977), which contained the first Cesium atomic clock to be placed in orbit, it was

recognized that orbiting clocks would require a relativistic correction, but there was uncertainty as to its magnitude as well as its sign. Indeed, there were some who doubted that relativistic effects were truths that would need to be incorporated [5]! A frequency synthesizer was built into the satellite clock system so that after launch, if in fact the rate of the clock in its final orbit was that predicted by general relativity, then the synthesizer could be turned on, bringing the clock to the coordinate rate necessary for operation.

....using the predictions of GR. The scientists let the system work without the correction , so , in one hour the receivers were missing by a block. So, the scientists turned the corrections on and the system started to work correctly. Thereafter, the frequency synthesizer was removed (in order to save cost) and the clocks aboard the satellites were preset to a lower frequency such as to compensate the speedup once they are in orbit. I showed that many posts ago.

 

 

 

Also of note is the Hafele–Keating experiment which as far as I can tell is only different from what Le Repteux was originally describbing by the clock being onboard a satellite vs an airplane.

 

Hafele-Keating has nothing in common with GPS with the exception that the experimenters flew atomic clocks (on counterpropagating planes). HK is about total elapsed proper time, GPS is about frequencies.

 

 

 

Suffices to say deriving time corrections to account for relavistic effects is clearly possible and one of the ways relativity has been validated.

 

Yes, GPS is a spectacular validation of GR.

[Le Repteux]

What is the difference between a frequency synthesizer and the electronic device that is actually used to incorporate the corrections sent from the ground or made before launching?

Edited September 9, 2014 by Le Repteux

[Skeptic134]

So, measuring the amount of drift is useless, you need to adjust the frequency (as it is being done, at launch). You do not know by how much to adjust the frequency UNLESS you apply the predictions of GR.

 

It is impossible to do it the way you want to do it,

 

At this point, I am not sure that you want to learn, I am becoming more and more convinced that you are intent on pushing your fringe ideas. You can't correct the clocks if you have no means to know what the correction should be.

 

I already did, earlier in the thread. Please go back and read, understand and stop trolling.

 

Well, you will have to read the answers in order to understand why it is not possible to do it "via empiricism".

 

All of the above posts of yours (and there are more this is just a sample) insist that it is impossible to have satellites in orbit with clocks and clocks on earth and to calculate the TD factor due GR as Le Repteux was suggesting could be done. This is wrong.

 

If that were true than the Hafele-Keating experiment too would have been impossible.

 

Hafele-Keating has nothing in common with GPS with the exception that the experimenters flew atomic clocks (on counterpropagating planes). HK is about total elapsed proper time, GPS is about frequencies.

 

 

 

Yes, GPS is a spectacular validation of GR.

 

No one said the Hafele-Keating experiment had anything to do with GPS... I pointed out that the only difference in that experiment used to measure TD effects and what Le Repteux was postulating was that the clocks were on satellites instead of in an airplane.

 

Yes, I believe we are all in agreement that GPS is consistent with relativity. We should also all be in agreement that TD effects of GR can be measured not only by an experiment such as the Hafele-Keating but also if the clocks were on satellites.

[xyzt]

 

 

 

 

 

All of the above posts of yours (and there are more this is just a sample) insist that it is impossible to have satellites in orbit with clocks and clocks on earth and to calculate the TD factor due GR as Le Repteux was suggesting could be done. This is wrong.

 

If that were true than the Hafele-Keating experiment too would have been impossible.

 

 

This is a non-sequitur. As I pointed out, there is no connection between HK and GPS.

 

 

 

No one said the Hafele-Keating experiment had anything to do with GPS... I pointed out that the only difference in that experiment used to measure TD effects and what Le Repteux was postulating was that the clocks were on satellites instead of in an airplane.[

 

So, if you agree that there is no connection between the two, your invoking HK in order to prop up Le Repeaux ideas is a non-starter.

 

 

 

Yes, I believe we are all in agreement that GPS is consistent with relativity. We should also all be in agreement that TD effects of GR can be measured not only by an experiment such as the Hafele-Keating but also if the clocks were on satellites.

 

GPS has nothing to do with "TD".

The GPS functionality relies on frequency (not time) adjustment based on a complex interplay of gravitational and kinematic effects. I

Edited September 9, 2014 by xyzt

[swansont]

GPS has nothing to do with "TD".

This contrariness is getting ridiculous. Time dilation is certainly a factor in GPS.

[Skeptic134]

Being able to admit mistakes is much more admirable than trying to convince yourself and/or others you've never made one.

 

It is/was a mistake to suggest that atomic clocks onboard a satellite and on earth could not be used to measure and calculate the effects of relativity on time and thus correct for it the same way that the Hafele-Keating experiment used atomic clocks on earth and in an airplane to perform said measurements.

This contrariness is getting ridiculous. Time dilation is certainly a factor in GPS.

 

Agreed, and I was under the impression xyzt was defending the consistency of GR and GPS up until that assertion.

[xyzt]

This contrariness is getting ridiculous. Time dilation is certainly a factor in GPS.

HK is about total elapsed proper time.

Time dilation is a totally different effect than total elapsed proper time.

The only relationship between HK and GPS is that they are both explained by GR and that they confirm two DIFFERENT predictions of GR.

 

 

It is/was a mistake to suggest that atomic clocks onboard a satellite and on earth could not be used to measure and calculate the effects of relativity on time

No one denies that. On the contrary, I explained how it is done in reality, not in some fantasy world.

 

 

 

and thus correct for it the same way that the Hafele-Keating experiment used atomic clocks on earth and in an airplane to perform said measurements.

 

1. HK doesn't correct anything.

2. HK and GPS are based on two different effects

3. The measurements of total elapsed proper time done in HK are not and cannot be used in any form or fashion for the frequency corrections applied to GPS. Since you appear to think differently, let's cut to the chase, show how you would perform the correction. I will point out the errors in your approach, just as I did it for Le Repteux.

Edited September 9, 2014 by xyzt

[swansont]

HK is about total elapsed proper time.

Time dilation is a totally different effect than total elapsed proper time.

The only relationship between HK and GPS is that they are both explained by GR and that they confirm two DIFFERENT predictions of GR.

Then why did H&K use the same equations as for time dilation in their paper?

[Le Repteux]

Hey Swansont, in my martini, I will take one part of xyzt and two parts of Skeptic134 please.

[xyzt]

Then why did H&K use the same equations as for time dilation in their paper?

1. The HK does NOT use the same equations as the GPS because there are NO equations in the HK paper.

 

2. In ADDITION , the HK paper is not very well written. Actually, it is very poorly written, the authors play very fast and loose with both the terminology AND the theory. This is one of the (many) reasons the paper has been criticized over time (the other reason, unrelated to our discussion is that the controls over the experiment were very poor). This is what happens when experimentalists dabble into theoretical physics.

Hey Swansont, in my martini, I will take one part of xyzt and two parts of Skeptic134 please.

Well, maybe you could collaborate on a paper that shows how you could adjust the satellite clock timing based on "empirical data". Who knows, I might get to referee it.

Edited September 9, 2014 by xyzt

[swansont]

there are NO equations in the HK paper.

Bull.

 

There are two papers. One theory, one experiment.

 

Around-the-World Atomic Clocks: Predicted Relativistic Time Gains has equations.

 

Science, New Series, Vol. 177, No. 4044. (Jul. 14, 1972), pp. 166-168.

 

[Le Repteux]

On second thought, make it one part Skeptic134 and two parts xyzt please, Swansont.

[xyzt]

Bull.

 

There are two papers. One theory, one experiment.

 

Around-the-World Atomic Clocks: Predicted Relativistic Time Gains has equations.

 

Science, New Series, Vol. 177, No. 4044. (Jul. 14, 1972), pp. 166-168.

 

This is the only one that shows up. Pretty crappy, by today's standards. Either way, you could be less rude. Or you could show how the formulas of the HK paper relate to the formulas explaining the functionality of the GPS I posted earlier in this thread.

Edited September 9, 2014 by xyzt

[swansont]

Either way, you could be less rude.

 

Pot, kettle, black.

 

I've had my fill here.